JP4332168B2 - antenna - Google Patents

Description

  The present invention relates to an antenna.

Terrestrial digital television broadcasting is expected to spread throughout Japan in 2006, and is expected to spread rapidly by the end of analog broadcasting in 2011.
As a technical feature of digital terrestrial television broadcasting, it is possible to remove a ghost (double image) due to time delay with respect to reflected incoming radio waves other than direct incoming radio waves from a broadcasting station. For this reason, the necessity of reception under favorable conditions by an outdoor antenna as in the conventional case is reduced, and the demand for reception by an indoor antenna instead increases rapidly.

However, in the reception by the indoor antenna, it is not clear from which direction the radio wave comes, and it is inconvenient to receive with a highly directional antenna such as a conventional television antenna (Yagi type antenna etc.) because it involves direction adjustment. is there.
In addition, even in indoor wireless LAN (Local Area Network), etc. that uses interference cancellation techniques similar to terrestrial digital television broadcasting, when building an indoor computer network, the network should be built without being aware of the access point. The antenna with strong directivity is difficult to use.
For this reason, it is expected that demand for omnidirectional or loosely directional antennas capable of transmitting and receiving incoming radio waves from any direction will increase in terrestrial digital television broadcasting.

  On the other hand, radio waves radiated from a linear antenna placed perpendicular to or close to the ground, such as an antenna used in a mobile phone, have an electric field whose vibration direction is mainly vertical. Because of the cylindrical symmetry of the shape of the radio wave radiation source (hereinafter referred to as vertical polarization), the radio wave radiation intensity of the antenna does not vary in the azimuth direction, and is easily omnidirectional.

In order to avoid interference with a wireless network such as a cellular phone, digital terrestrial television broadcasting and some wireless LANs use horizontally polarized waves in which the vibration direction of the electric field is mainly horizontal.
For example, in order to emit horizontal polarization with a linear antenna, as shown in FIG. 16A, when an XY plane is assumed to be a horizontal plane, an antenna element constituted by the linear conductor 1 is placed parallel to the XY plane. There is a need. However, in this case, the radio wave radiation from the antenna element always has a directivity of “8” like the pattern P1 in FIG. 16B, and therefore 30 ° to 45 centered on the 90 ° direction and the 270 ° direction. There will be a direction insensitive to radio waves.

As the most reliable method for solving the problem of the direction of insensitive to radio waves, conventionally, as shown in FIG. 17A, antenna elements composed of two linear conductors 1 and 2 are arranged at right angles to each other on the XY plane. In some cases, the feeding points 1a and 2a are fed with the feeding phase shifted. The same omnidirectional antenna is also described in paragraphs (0009) and (0017) to (0019) of Patent Document 1 below. In these antennas, the radio wave radiation intensity is almost omnidirectional as in the pattern P2 in FIG.
JP 11-1227027 A

However, the antenna shown in FIG. 17A requires two feeding points 1a and 2a.
In order to supply power to each of the power supply points 1a and 2a from one power source 4, as shown in FIG. 18, the power distributor 3 that makes the power distribution balance to each of the power supply points 1a and 2a completely equal is always required. Necessary. However, particularly when an antenna is used in an extremely wide frequency band as in television broadcasting, the power distributor 3 that stabilizes the power distribution balance over a wide band is expensive. On the other hand, if the power distributor 3 is defective, efficient transmission / reception of radio waves cannot be expected no matter how the antenna performance is improved.

  On the other hand, as shown in FIG. 19 (a), when the two power supply points 1a and 2a are directly connected without using the power distributor 3 and power is supplied at the same power supply phase, the radio wave radiation intensity is as shown in FIG. 19 (b). Pattern P3, and the drop in radio wave radiation intensity is slightly relieved compared to pattern P1, but pattern P1 is slightly tilted, and the effect of increasing the occupied volume of the antenna cannot be found.

  On the other hand, as a method of providing only one feeding point only for the linear conductor 1 and feeding the power, and to prevent a radio wave insensitive direction like the pattern P1 in FIG. As described above, there is a method of bending both ends of the linear conductor 1 at a right angle or an arc. By doing so, a part of the current flowing through the linear conductor 1 flows in a direction perpendicular to the linear conductor 1, and an effect of canceling the radio wave insensitive direction by radio wave radiation by this is obtained. Actually, when both ends of the linear conductor 1 are bent at a right angle by 1/6 of the entire length, there is no orientation in which the radio wave radiation intensity drops rapidly as in the pattern P4 in FIG.

  In addition, as shown in FIG. 21A, another method for installing and feeding only one feeding point to relieve the insensitive direction of the radio wave is linear on one side of the feeding point 1a of the linear conductor 1. There is one in which a linear conductor 1b having a half length of the conductor 1 is added so as to have a T-shape. In this case, as shown by a pattern P5 in FIG. 21B, one of the 90 ° radio insensitive directions of the pattern P1 in FIG. 16 is eliminated, but the radio insensitive direction near 270 ° is not eliminated.

Here, bandwidth comparison is performed when an antenna having one feeding point described so far is applied to an antenna for digital terrestrial television broadcasting.
The frequency band allocated for terrestrial digital television broadcasting is 470 MHz to 720 MHz, and the center frequency is approximately 600 MHz.

  The antenna 10 in FIG. 22 (a) is a half-wave dipole antenna corresponding to the antenna in FIG. 16 (a), but assuming that the center frequency of the reception frequency is 600 MHz, which is the center frequency of digital terrestrial television broadcasting, The antenna length L1 is 250 mm.

  The antenna 20 in FIG. 22B is a half-wave dipole antenna corresponding to the antenna in FIG. 20A, and both ends are bent vertically. Assuming that the center frequency of the reception frequency of the antenna 20 is 600 MHz, which is the center frequency of digital terrestrial television broadcasting, the antenna length L2 is 150 mm, and the lengths D2 of the bent portions at the ends are 50 mm.

  The antenna 30 in FIG. 22C is a half-wavelength dipole antenna corresponding to the antenna in FIG. 21A, and a vertical linear conductor is added in the vicinity of the central feeding point so as to form a T shape. ing. Assuming that the center frequency of the reception frequency of the antenna 30 is the center frequency of digital terrestrial television broadcasting, the antenna length L3 of the antenna 30 is 250 mm, and the length D3 of the linear conductor is 125 mm (= L3 / 2).

  When the characteristics of the frequency versus standing wave ratio (VSWR) are investigated for each of these antennas 10, 20, and 30, the characteristic curves C1, C2, and C3 in FIG. 23 are obtained, respectively.

  The horizontal axis in FIG. 23 represents frequency, and the vertical axis in FIG. 23 represents VSWR. VSWR indicates the ratio of “belly” and “node” of “buzz” that is generated by combining the voltage that the power supply supplies to the antenna from the feeding point and the voltage that is reflected from the antenna. If this doesn't happen, the minimum is 1.

  In a terrestrial digital television receiving antenna, VSWR is required to be "3" or less. The wireless LAN antenna is required to have a VSWR of “2” or less.

An area A shown in FIG. 23 is an area where the VSWR is “3” or less in the frequency band assigned for terrestrial digital television broadcasting. In contrast to the characteristic curve C1 of the antenna 10, the characteristic curve 20 of the antenna 20 shows that the band where VSWR is 3 or less is significantly narrower than C1. That is, as described above, the antenna 20 is effective in eliminating the radio wave insensitive direction with respect to the antenna 10, but has a narrow band.
The characteristic curve C3 of the antenna 30 has the widest frequency range where VSWR is 3 or less. In other words, the antenna 30 has a wide band, but the radio wave insensitive direction cannot be resolved.

  It is an object of the present invention to realize an antenna with a wide bandwidth as well as an antenna with reduced omnidirectionality or directivity.

In order to achieve the above object, an antenna according to the first aspect of the present invention provides:
A first transmission / reception unit formed of a linear conductor having one end connected to a feeding point;
A linear second transmission / reception unit formed of a linear conductor having one end connected to the feeding point, and arranged symmetrically with the first transmission / reception unit across the feeding point;
It is formed of a conductor extending from the other end of the first transmission / reception unit, and is a linear third direction facing a second direction perpendicular to the first direction toward the first transmission / reception unit. A transmission / reception unit;
A linear fourth transmission / reception unit formed of a conductor extending from the other end of the second transmission / reception unit and facing the second direction;
A linear fifth transmission / reception unit formed of a conductor having one end connected in the vicinity of the feeding point of the first transmission / reception unit and facing the second direction;
A sixth transmission / reception unit formed of a linear conductor, one end connected to the tip of the third transmission / reception unit, and the other end connected to the other end of the fifth transmission / reception unit;
It is characterized by providing .

  In this case, the length of the third transmission / reception unit may be equal to the length of the fifth transmission / reception unit.

In order to achieve the above object, an antenna according to the second aspect of the present invention provides:
It is formed of a strip-shaped conductor having one side facing the first direction and the opposite side facing away from the one side by a predetermined distance in a second direction perpendicular to the first direction. A first transmission / reception unit connected to the point;
It is formed by a strip-shaped conductor having one side facing the first direction and the opposite side facing away from the one side by a predetermined distance in the second direction, and the one side is connected to the feeding point and the power feeding A second transmission / reception unit facing one side of the first transmission / reception unit across a point;
A third transmission / reception unit formed of a strip-shaped conductor and extending from the opposite side of the first transmission / reception unit in a third direction perpendicular to the first direction and the second direction;
A fourth transmission / reception unit formed of a strip-shaped conductor and extending in the third direction from the opposite side of the second transmission / reception unit ;
A fifth conductor which is formed of a strip-shaped conductor and protrudes in the third direction from the vicinity of the one side of the first transmission / reception unit and faces the third transmission / reception unit and the fourth transmission / reception unit. The transmitter / receiver of
Formed by a strip-shaped conductor having one side facing the first direction and the opposite side opposite to the one side, the opposite side is provided at the tip of the third transmitting / receiving unit extending from the first transmitting / receiving unit. A sixth transmission / reception unit having one side connected to the tip of the fifth transmission / reception unit projecting from the first transmission / reception unit;
It is characterized by providing.

Incidentally, formed in a strip-like conductor having an opposite side facing the one side and the one side facing the first direction, the leading end of the first third extending from wave transceiver section of the wave transceiver section You may provide the 6th transmission / reception part by which this one side was connected to the front-end | tip of the said 5th transmission / reception part projecting from this 1st transmission / reception part to which this opposite side was connected.

  In this case, the length in the third direction of the third transmission / reception unit extending from the first transmission / reception unit and the fifth transmission / reception unit protruding from the first transmission / reception unit The length in the third direction may be equal.

The first transmission / reception unit, the third transmission / reception unit, the fifth transmission / reception unit, and the sixth transmission / reception unit are supported by the first transmission / reception unit, the third transmission / reception unit, and the third transmission / reception unit. You may provide the cover member which covers the space enclosed by the wave part, this 5th transmission / reception part, and this 6th transmission / reception part.
The feeding point may be connected to one side of the first transmission / reception unit and an end of one side of the second transmission / reception unit.

In order to achieve the above object, an antenna according to the third aspect of the present invention provides:
A first transmission / reception formed of a strip-shaped conductor having one side facing the first direction and an opposite side opposite to the one side, the one side being connected to a feeding point and curved in a plane perpendicular to the one side Namibe,
It is formed of a strip-shaped conductor having one side facing the first direction and the opposite side opposite to the one side, and the one side is connected to the feeding point and is bent in the plane so that the inner peripheral surface is A second transmission / reception unit facing the inner peripheral surface of the first transmission / reception unit;
It is formed of a strip-shaped conductor, protrudes from the vicinity of one side of the first transmission / reception unit and faces the inner peripheral surface of the first transmission / reception unit, and the inner peripheral surface of the second transmission / reception unit A third transmission / reception unit facing
It is formed of a strip-shaped conductor having one side facing the first direction and the opposite side opposite to the one side, the one side is connected to the opposite side of the first transmission / reception unit, and the opposite side is the first transmission / reception unit A fourth transmission / reception unit connected to the tip of the third transmission / reception unit projecting from the wave unit;
It is characterized by providing.

Incidentally, the formed by the first strip-shaped conductor having a opposite side opposite to one side and the one side facing the direction, the one side is connected to the opposite side of the first wave transceiver section, the pair sides first You may provide the 4th transmission / reception part connected to the front-end | tip of the said 3rd transmission / reception part protrudingly provided from this transmission / reception part.

  In this case, the first transmission / reception unit may draw an arc having a central angle of 90 ° by the curvature.

The first transmission / reception unit, the third transmission / reception unit, and the fourth transmission / reception unit are supported by the first transmission / reception unit, the third transmission / reception unit, and the fourth transmission / reception unit. You may provide the cover member which covers the space enclosed by the wave part.
The feeding point may be connected to one side of the first transmission / reception unit and an end of one side of the second transmission / reception unit.

  According to the present invention, it is possible to realize an antenna having a wide frequency band as well as an antenna having omnidirectionality or gentle directivity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIGS. 1A and 1B are diagrams showing two examples of antennas 40 and 50 according to the first embodiment of the present invention.

The two examples of the antennas 40 and 50 according to this embodiment are both formed of a linear conductor.
As shown in FIG. 1A, the antenna 40 has a first transmission / reception unit 42 formed of a linear conductor having one end connected to a feeding point 41, and one end connected to the feeding point 41. A linear second wave transmission / reception unit 43 is provided that is formed of a linear conductor and is symmetrically disposed on the first wave transmission / reception unit 42 with the feeding point 41 interposed therebetween.

  At the other end of the first transmission / reception unit 42, a third transmission / reception unit 44 that is formed of a linear conductor and faces in a direction perpendicular to the direction in which the first transmission / reception unit 42 faces is extended. ing. At the other end of the second transmission / reception unit 43, a linear fourth transmission / reception unit 45 that is formed of a linear conductor and faces the third transmission / reception unit 44 in parallel is extended.

  In the vicinity of the feeding point 41 of the first transmission / reception unit 42, a fifth transmission / reception unit 46 formed of a linear conductor and parallel to the third transmission / reception unit 44 and the fourth transmission / reception unit 45 is provided. Projected.

  The length D4a of the third transmission / reception unit 44 and the fourth transmission / reception unit 45 are equal, and the length D4b of the fifth transmission / reception unit 46 is the same as the third transmission / reception unit 44 and the fourth transmission / reception unit 45. Is longer than the length D4a, and has a “mountain” shape as a whole.

  The length D4a of the third transmission / reception unit 44 and the fourth transmission / reception unit 45 is selected from about 0.1 to about 0.15 wavelength with respect to the design wavelength of the radio wave to be transmitted / received. This is preferable. If the length L4 from the other end of the first transmission / reception unit 42 to the other end of the second transmission / reception unit 43 is selected so that L4 + 2 × D4a = half wavelength, the transmission / reception efficiency is good. In addition, the length D4b of the fifth transmission / reception unit 46 is preferably about ¼ wavelength of the design wavelength in order to reduce directivity.

Here, assuming that the frequency band (470 MHz to 720 MHz) allocated for terrestrial digital television broadcasting is transmitted and the center frequency is assumed to be 600 MHz, the design wavelength is 0.5 m.
The shape of the antenna 40 with a design wavelength of 0.5 m is, for example, L4 = 170 mm, D4a = 50 mm, and D4b = 125 mm. When the directivity is investigated using the antenna 40 of this size, it is as shown in FIG.

FIG. 2 is an explanatory diagram showing the directivity of the antenna 40 of FIG.
FIG. 2 shows the ratio of the radiated power intensity in an arbitrary direction expressed in decibels when the radiated power intensity when the power injected into the antenna is radiated uniformly in all directions is set as a reference (= 0 dBi). It is. Hereinafter, the directivity of each antenna is evaluated in the same manner for directivity.

  Assuming that the direction of the first transmitting / receiving unit 42 and the second transmitting / receiving unit 43 of the antenna 40 is the Y axis direction and the direction of the third to fifth transmitting / receiving units 44 to 46 is the X axis direction, the Y axis Although the sensitivity is low in the direction, no extreme radio wave insensitive direction appears in the vicinity of 270 ° in FIG. 21 like the directivity of the antenna 30 described above. That is, the antenna 40 is more omnidirectional than the antenna 30.

  On the other hand, the antenna 50 of FIG. 1B has a first transmission / reception unit 52 formed of a linear conductor having one end connected to the feeding point 51 and a linear shape having one end connected to the feeding point 51. And a linear second wave transmitting / receiving unit 53 arranged symmetrically with the first wave transmitting / receiving unit 52 with the feeding point 51 interposed therebetween.

  At the other end of the first transmission / reception unit 52, a linear third transmission / reception unit 54 that is formed of a conductor and extends in a direction perpendicular to the direction in which the first transmission / reception unit 52 faces is extended. ing. At the other end of the second transmission / reception unit 53, a linear fourth transmission / reception unit 55 that extends in parallel with the third transmission / reception unit 54 is extended.

  A fifth transmission / reception unit 56 is formed of a linear conductor in the vicinity of the feeding point 51 of the first transmission / reception unit 52, and the third transmission / reception unit 54 and the fourth transmission / reception unit 55 face each other in parallel. Is connected. The tip of the third transmission / reception unit 54 and the other end of the fifth transmission / reception unit 56 are connected by a sixth transmission / reception unit 57 formed of a linear conductor, and the entire antenna 50 is “6”. It is a letter shape.

The lengths D5b of the fifth transmission / reception unit 56 and the third transmission / reception unit 54 are equal, and are longer than the length D5a of the fourth transmission / reception unit 55.
In the antenna 50, it is effective in terms of directivity to select the length D5a of the fourth transmission / reception unit 55 from the design wavelength of about 0.1 to about 0.2. The entire length L5a of the first transmission / reception unit 52 and the second transmission / reception unit 53 is about 0.3 to 0.4 wavelengths of the design wavelength, and the length L5b of the first transmission / reception unit 52 is half that length. It is efficient to select from about 0.15 wavelength to about 0.2 wavelength. In addition, it is preferable in terms of directivity that the length D5b of the third transmission / reception unit 54 and the fifth transmission / reception unit 56 is selected to be approximately D5b = L5b.

  Here, assuming that the frequency band (470 MHz to 720 MHz) allocated for terrestrial digital television broadcasting is transmitted and received and the center frequency is assumed to be 600 MHz, the length of each part of the antenna 50 is L5a = 170 mm, D5a = 50 mm and L5b = 85 mm. When the directivity is investigated using the antenna 50 of this size, it is as shown in FIG.

FIG. 3 is an explanatory diagram showing the directivity of the antenna 50 of FIG.
The direction in which the first transmission / reception unit 52, the second transmission / reception unit 53, and the sixth transmission / reception unit 57 of the antenna 50 are directed is the Y-axis direction, and the direction in which the third to fifth transmission / reception units 54-56 are directed. In the X-axis direction, the antenna 30 is more omnidirectional than the antenna 30 and is more omnidirectional than the antenna 40.

FIG. 4 is an explanatory diagram of the bands of the antenna 40 and the antenna 50 and shows the VSWR characteristics.
A characteristic curve C2 shown in FIG. 4 shows the VSWR of the antenna 20 described above. The antenna 20 was effective in eliminating the radio wave insensitive direction, but the band where the VSWR is 3 or less is narrow. On the other hand, the characteristic curve C4 of VSWR of the antenna 40 of this embodiment has a wide band where VSWR is 3 or less. That is, the bandwidth of the antenna 40 is expanded so that the VSWR is 3 or less while maintaining the effect of eliminating the radio wave insensitive direction. On the other hand, the VSWR of the antenna 50 of the present embodiment is the characteristic curve C5 of FIG. 4, and the band where the VSWR is 3 or less further increases.

  As described above, the antennas 40 and 50 according to the present embodiment sufficiently eliminate the radio wave insensitive direction and have a wide bandwidth.

[Second Embodiment]
5A and 5B are perspective views showing two examples of the antennas 60 and 70 according to the second embodiment of the present invention.
FIG. 6 is a diagram showing a configuration of the antenna 60 of FIG.
The antenna 60 is composed of a strip-shaped conductor. Similarly, the antenna 70 is also formed of a strip-shaped conductor, and a housing portion in which a signal processing unit can be installed and a small amplifier can be inserted is formed.
Before describing the details of the antenna 60 and the antenna 70, the reason why the strip-shaped conductor is used will be described.

FIGS. 7A, 7B, and 7C are diagrams showing the antenna 10 formed of a linear conductor and the antennas 10A and 10B formed of a strip-shaped conductor.
FIG. 8 is a diagram illustrating the VSWR characteristics of the antennas 10, 10A, and 10B.

  A region A shown in FIG. 8 indicates a region where the VSWR is 3 or less in the frequency band assigned to terrestrial digital television broadcasting. In the antenna 10 composed of the above-described linear conductor, as shown by the characteristic curve C1 in FIG. 8, the band where the VSWR is 3 or less is narrow.

  In the antenna 10 having a linear conductor, the frequency at which a standing wave current having a “node” at the center and a “node” at the end is limited, so the bandwidth of the antenna 10 is narrow anyway. Become. As a method for solving this problem, it is conceivable to use a strip-shaped conductor instead of the linear conductor. When this method is employed, the linear conductors on both sides of the feeding point are replaced with strip conductors as in the antenna 10A of FIG. Since the current spreads widely on the strip-shaped conductor, various standing wave currents can be induced on the conductor, and the bandwidth of the antenna 10A is expanded.

  However, when a standing wave current is induced, the maximum current path length is at most about half of the circumference of the strip conductor, and the difference from the lateral width W1 / 2 of the strip conductor 5 which is the minimum current path length is too wide. Absent. On the other hand, when the feeding point is moved to the lower end of the strip-shaped conductor as in the antenna 10B of FIG. 7C, the difference between the maximum current path length and the minimum current path length widens. It can be induced on the conductor, and the bandwidth of the antenna 10B is expanded.

  When the width W1 of the strip-shaped conductors of the antennas 10A and 10B is W1 = 250 mm, the height H1 is H1 = 40 mm, and the gap G is G = 2 mm, the VSWR characteristics of the antennas 10A and 10B are characteristic curves of FIG. C6 and C7.

  In the antenna 10A, the bandwidth in which the VSWR is 3 or less is expanded, and exceeds the region A in which the VSWR is 3 or less in the frequency band assigned to the terrestrial digital television broadcast. In particular, the characteristic curve C7 of the antenna 10B when the feeding point is arranged at the lower end of the conductor is higher than the characteristic curve C6 of the antenna 10A when the feeding point is placed at the center of the side of the strip-shaped conductor. The bandwidth in which the VSWR is 3 or less is further expanded even if the antenna has the same stretchability and the same antenna size.

The antenna 60 and the antenna 70 of the present embodiment utilize the above phenomenon.
The antenna 60 is formed of a strip-shaped conductor, and is formed of a first transmission / reception unit 62 in which the center of one of the two opposing short sides is connected to the feeding point 61, and a strip-shaped conductor, The center of one short side of the two short sides facing each other is connected to the feeding point 61, and the first short side faces the first short side of the first transmission / reception unit 62 across the feeding point 61. And a wave portion 63.

  A third transmission / reception unit 64 formed of a strip-shaped conductor extends vertically from one short side of the first transmission / reception unit 62 on the side not connected to the feeding point 61. From one short side of the second transmission / reception unit 63 that is not connected to the feeding point 61, a fourth transmission / reception unit 65 formed of a strip-shaped conductor faces the third transmission / reception unit 64 in parallel. So as to extend vertically.

  In the vicinity of the feeding point 61 of the first transmission / reception unit 62, a fifth transmission / reception wave 66 formed of a strip-shaped conductor and opposed to the third transmission / reception unit 64 and the fourth transmission / reception unit 65 protrudes. It is installed. The leading end of the third transmitting / receiving unit 64 and the leading end of the fifth transmitting / receiving unit 66 are connected by a sixth transmitting / receiving unit 67 formed of a strip-shaped conductor.

  On the other hand, the antenna 70 has substantially the same configuration, is formed of a strip-shaped conductor, and has a first transmission / reception unit 72 in which the center of one of the two opposing short sides is connected to the feeding point 71. The center of one short side of two opposing short sides is connected to the feeding point 71, and one short side of the first transmission / reception unit 72 sandwiches the feeding point 71. And a second transmission / reception unit 73 facing the short side.

  A third transmission / reception unit 74 formed of a strip-shaped conductor extends vertically from one short side of the first transmission / reception unit 72 that is not connected to the feeding point 71. From one short side that is not connected to the feeding point 71 of the second transmission / reception unit 73, a fourth transmission / reception unit 75 formed of a strip-shaped conductor faces the third transmission / reception unit 74 in parallel. So as to extend vertically.

  In the vicinity of the feeding point 71 of the first transmission / reception unit 72, a fifth transmission / reception wave 76 that is formed of a strip-shaped conductor and faces the third transmission / reception unit 74 and the fourth transmission / reception unit 75 protrudes. It is installed. The distal end of the third transmission / reception unit 74 and the distal end of the fifth transmission / reception unit 76 are connected by a sixth transmission / reception unit 77 formed of a strip-shaped conductor.

  Unlike the antenna 60, the antenna 70 is provided with a lid 78. The lid 78 is installed on the long sides of the first transmission / reception unit 72, the third transmission / reception unit 74, the fifth transmission / reception unit 76, and the sixth transmission / reception unit 77, and the first transmission / reception unit 72. The space surrounded by the third transmission / reception unit 74, the fifth transmission / reception unit 76, and the sixth transmission / reception unit 77 is used as a storage unit for installing a signal processing unit or inserting a small amplifier.

  The dimensions of these antennas 60 and 70 are substantially the same as those of the antenna 50 of the first embodiment, except that each of the first to sixth transmission / reception units 62 to 67 and 72 to 77 has a strip shape. . That is, the length ED1 of the fourth transmission / reception units 65 and 75 is selected from the design wavelength of about 0.1 to about 0.2, as in the case of the length D5b of the antenna 50. Is. The overall length W2 of the first transmission / reception units 62 and 72 and the second transmission / reception unit 63.73 is the same as the length L5a of the antenna 50, which is about 0.3 or 0.4 wavelengths of the design wavelength. The length E2 of the first transmission / reception units 62 and 72 is efficient when selected from about 0.15 wavelength to about 0.2 wavelength, like the length L5b of the antenna 50. Further, the length ED1 of the third transmission / reception units 64, 74 and the fifth transmission / reception units 66, 76 is preferably set to about ED1 = E2 from the viewpoint of directivity.

  The width H2 of the first to sixth transmission / reception units 62 to 67 and 72 to 77 increases as the antenna occupying volume is not restricted, and the bandwidth of the antenna becomes wider. Is. If the gap G between one short side of the first transmission / reception units 62 and 72 and one short side of the second transmission / reception units 63 and 73 facing the first transmission / reception unit 62 and 72 is narrower, the bandwidth of the antenna becomes wider. Since VSWR deteriorates conversely, about 1/200 to 1/100 of the design wavelength is appropriate.

Here, assuming that the frequency band (470 MHz to 720 MHz) allocated for terrestrial digital television broadcasting is transmitted and the center frequency is assumed to be 600 MHz, the length of each part of the antennas 60 and 70 is E2 = 170 mm. W2 = 170 mm, ED1 = 85 mm, ED2 = 50 mm, H2 = 40 mm, and G = 2 mm.
When the VSWR is measured using the antennas 60 and 70 of this size, the characteristics shown in FIG. 9 are obtained.

FIG. 9 is an explanatory diagram showing the VSWR characteristics of the antennas 60 and 70 shown in FIGS.
FIG. 9 shows a characteristic curve C8 indicating the VSWR of the antenna 60 and a characteristic curve C9 indicating the VSWR of the antenna 70. For reference, the VSWR is 3 in the frequency band allocated for terrestrial television broadcasting. The following region A and a characteristic curve C7 indicating the VSWR of the antenna 10B are shown.

  As shown by the characteristic curve C8 in FIG. 9, the antenna 60 created for terrestrial digital television broadcasting has a VSWR of 3 or less over the entire band relative to the frequency band assigned to terrestrial television broadcasting. It becomes.

  Similarly to the antenna 60, the antenna 70 created for the terrestrial digital television broadcast is similar to the antenna 60, as shown by the characteristic curve C9 in FIG. 3 or less.

10A, 10B, and 10C are explanatory diagrams showing the directivity of the antenna 70 in FIG. 5B.
For the antenna 70, the direction of the long side of the first transmission / reception unit 72 is the Y-axis direction, the direction in which the third transmission / reception unit 74 is extended is the X-axis direction, and the short side of the first transmission / reception unit 72. When the directivity is examined with the direction facing as Z-axis direction, the results shown in FIGS. 10A, 10B, and 10C are obtained.

  10 (a), (b), and (c) show the radiated power intensity when the power injected into the antenna is uniformly radiated in all directions as a reference (= 0 dBi), and the radiated power intensity in an arbitrary direction. The ratio is expressed in decibels.

  In the electromagnetic wave of 470 MHz, which is the lower limit of the frequency band assigned to digital terrestrial television broadcasting, the antenna 70 has the largest difference in radiated power intensity in the azimuth direction as shown in FIG. The resolution is almost achieved. The ratio of the radiant power intensity in an arbitrary direction is as shown in FIG. 10B at 620 MHz in the middle range of the frequency assigned to the terrestrial digital television broadcast, and at 710 MHz near the upper limit of the frequency assigned to the terrestrial digital television broadcast. As shown in FIG. That is, as the frequency is higher, the ratio of the radiated power intensity in an arbitrary direction becomes closer to a circle, and the radiation directivity becomes gentle even if a single feeding point 71 is used without using a plurality of antennas. Since the antenna 70 has only the lid member 78 added to the antenna 60, the antenna 60 has the same characteristics as the antenna 70 with respect to directivity.

  As described above, according to the present embodiment, the antennas 60 and 70 maintain a state in which the directivity is relaxed, and the bandwidth is wider than the antennas 40 and 50 of the first embodiment. ing.

[Third Embodiment]
11 (a) and 11 (b) are views showing an antenna 80 according to a third embodiment of the present invention. FIG. 11 (a) is a perspective view, FIG. 11 (b) is a front view, and FIG. A side view is shown.

  In the second embodiment, the antennas 60 and 70 using the strip-shaped conductor have been described. In the third embodiment, the antenna 80 using the strip-shaped conductor having a curvature is described.

  The antenna 80 is formed of a strip-shaped conductor, one end of the strip-shaped end facing the width direction is connected to the feeding point 81, and a first transmission / reception unit 82 bent in a plane perpendicular to the width direction; It is formed of a strip-shaped conductor, and one end of the strip-shaped side facing the width direction is connected to the feeding point 81 and is bent in a plane perpendicular to the width direction so that the inner peripheral surface of the first transmitting / receiving unit 82 A second wave transmitting / receiving unit 83 facing the inner peripheral surface is provided. The first transmission / reception unit 82 draws an arc having a central angle of 90 ° by bending. The second transmission / reception unit 83 also draws an arc having a central angle of 90 ° due to curvature.

  From the vicinity of one end of the first transmission / reception unit 82, a third transmission / reception unit that faces the inner peripheral surface of the first transmission / reception unit 82 and faces the inner peripheral surface of the second transmission / reception unit 83. 84 protrudes. The distal end of the third transmission / reception unit 84 and the other end side of the first transmission / reception unit 82 are connected by a fourth transmission / reception unit 85 formed of a strip-shaped conductor.

  Similar to the antenna 70, the antenna 80 is provided with a lid 86. The lid 86 is provided on the longitudinal sides of the first transmission / reception unit 82, the third transmission / reception unit 84, and the fourth transmission / reception unit 85, and the first transmission / reception unit 82, the third transmission / reception unit. 84, the space surrounded by the fourth transmission / reception unit 85 is a storage unit in which a signal processing unit is installed or a small amplifier is inserted.

  The radius of curvature R of the arc-shaped first transmitting / receiving unit 82 and second transmitting / receiving unit 83 of the antenna 80 is R = 90 mm, and the width H3 of the first to fourth transmitting / receiving units 82-85 is H3 = 40 mm. Furthermore, when the gap G between one side connected to the feeding point 81 of the first transmission / reception unit 82 and one side connected to the feeding point 81 of the second transmission / reception unit 83 is G = 2 mm. When the VSWR is examined, it is as shown in FIG.

FIG. 12 is an explanatory diagram showing the VSWR of the antenna 80 of FIGS. 11 (a) and 11 (b).
FIG. 12 shows a characteristic curve C10 indicating the VSWR of the antenna 80. For reference, a region A in which the VSWR is 3 or less in the frequency band allocated for terrestrial television broadcasting and the VSWR of the antenna 70 are shown. A characteristic curve C9 is shown.

  For the VSWR characteristic curve C9 of the antenna 70 described in the second embodiment. The characteristic curve C10 indicating the VSWR of the antenna 80 is almost the same, and the VSWR required in the frequency band assigned to terrestrial digital television broadcasting is 3 or less in the entire area.

FIGS. 13A, 13B and 13C are explanatory diagrams showing the directivity of the antenna 80 shown in FIGS. 11A and 11B.
For the antenna 80, the contact direction of the portion connected to the feeding point 81 of the first transmission / reception unit 82 is the Y-axis direction, the extending direction of the third transmission / reception unit 84 is the X-axis direction, and the first transmission / reception is performed. When the directivity is examined with the width direction of the wave portion 82 as the Z-axis direction, the results shown in FIGS. 13A, 13B, and 13C are obtained.

  In the antenna 80, the difference in radiant power intensity in the azimuth direction is smaller than that of the antenna 70 at all frequencies of 470 MHz, which is the lower limit of the frequency band assigned to terrestrial digital television broadcasting, 620 MHz in the middle range, and 710 MHz near the upper limit. However, it is clear that it is close to omnidirectionality. Specifically, the maximum difference in radiated power intensity in the azimuth direction by the antenna 70 is about 12 dB, whereas in the antenna 80 of this embodiment, the maximum difference in radiated power intensity in the azimuth direction is compressed to 9 dB. .

  As described above, the antenna 80 of the present embodiment has a sufficiently wide frequency band and is more omnidirectional than the antenna 70, as with the antenna 70 of the second embodiment.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. Examples of such modifications include the following.
(1) The dimensions of each part of the antennas 40, 50, 60, 70, and 80 shown in the first to third embodiments are not limited to those described in the embodiments, and depend on the frequency band of electromagnetic waves to be transmitted and received. May be changed.

  (2) The antenna 60 described in the second embodiment is obtained by changing the conductor of the “6” -shaped antenna 50 of the first embodiment into a strip-shaped conductor, and has a wide band. Similarly, the “mountain” -shaped antenna 40 of the first embodiment can be expected to expand the band by changing the conductor to a strip-shaped conductor as shown in FIG.

FIG. 14 is a perspective view showing an antenna 90 which is a modification of the antenna 40 of FIG.
The antenna 90 is formed of a strip-shaped conductor, and includes a first transmission / reception unit 92 in which an end of one short side of two opposing short sides of the strip is connected to a feeding point 91, and a strip-shaped conductor. The end of one short side of the two opposing short sides of the strip shape is connected to the feeding point 91, and the one short side is one short of the first transmission / reception unit 92 across the feeding point 91. A second transmission / reception unit 93 facing the side is provided.

  A third transmission / reception unit 94 formed of a strip-shaped conductor extends vertically from one short side of the first transmission / reception unit 92 that is not connected to the feeding point 91. From one short side of the second transmission / reception unit 93 that is not connected to the feeding point 91, a fourth transmission / reception unit 95 formed of a strip-shaped conductor faces the third transmission / reception unit 94 in parallel. So as to extend vertically.

  In the vicinity of the feeding point 91 of the first transmission / reception unit 92, a fifth transmission / reception wave 96 formed of a strip-shaped conductor and opposed to the third transmission / reception unit 94 and the fourth transmission / reception unit 95 protrudes. It is installed. The lengths of the third transmission / reception unit 94 and the fourth transmission / reception unit 95 are equal, and the fifth transmission / reception unit 96 is longer than the third transmission / reception unit 94 and the fourth transmission / reception unit 95, As a “mountain” character.

  (3) The antenna 80 of the third embodiment includes a lid 86 and forms a storage unit in which a signal processing unit is installed or a small amplifier is inserted. Since there is no change in the band, it is expected that the antenna 100 without the lid 86 as shown in FIG.

FIG. 15 is a diagram showing an antenna 100 which is a modification of the antenna 80 of FIG.
The antenna 100 is formed of a strip-shaped conductor, one end of the strip-shaped end facing the width direction is connected to the feeding point 101, and a first transmission / reception unit 102 bent in a plane perpendicular to the width direction; It is formed of a strip-shaped conductor, and one end of the strip-shaped side facing the width direction is connected to the feeding point 101 and is bent in a plane perpendicular to the width direction so that the inner peripheral surface of the first transmitting / receiving unit 102 And a second wave transmitting / receiving unit 103 facing the inner peripheral surface. The first transmission / reception unit 102 draws an arc having a central angle of 90 ° by bending. The second transmission / reception unit 103 also draws an arc having a central angle of 90 ° due to curvature.

  From the vicinity of one end of the first transmission / reception unit 102, a third transmission / reception unit that faces the inner peripheral surface of the first transmission / reception unit 102 and faces the inner peripheral surface of the second transmission / reception unit 103. 104 is protrudingly provided. The distal end of the third transmission / reception unit 104 and the other end side of the first transmission / reception unit 102 are connected by a fourth transmission / reception unit 105 formed of a strip-shaped conductor.

  (4) At the feeding points 61, 71, 91 of the antennas 60, 70, 90, the ends of one short side of the strip-shaped first transmission / reception units 62, 72, 92 and the strip-shaped second transmission / reception. The ends of one short side of the parts 63, 73, 93 are connected, but the center part of each one short side may be connected.

  Similarly, at the feeding points 81 and 101 of the antennas 80 and 100, one end of one short side of the strip-shaped first transmission / reception units 82 and 102 and one of the strip-shaped second transmission / reception units 83 and 103 are provided. Although the end part of a short side is connected, the center part of each 1 short side may be connected.

It is a figure which shows the antenna of 2 examples based on the 1st Embodiment of this invention. It is explanatory drawing which shows the directivity of the antenna of Fig.1 (a). It is explanatory drawing which shows the directivity of the antenna of FIG.1 (b). It is explanatory drawing of the band of the antenna of Fig.1 (a), (b). It is a perspective view which shows the antenna of 2 examples based on the 2nd Embodiment of this invention. It is a figure which shows the structure of the antenna of Fig.5 (a). It is a figure which shows the antenna comprised by the antenna comprised with the linear conductor, and a strip-shaped conductor. It is a figure which shows the VSWR characteristic of the antenna of Fig.7 (a)-(c). It is explanatory drawing which shows the VSWR characteristic of the antenna of Fig.5 (a), (b). It is explanatory drawing which shows the directivity of the antenna of FIG.5 (b). It is a figure which shows the antenna which concerns on the 3rd Embodiment of this invention. It is explanatory drawing which shows VSWR of the antenna of Fig.11 (a), (b). It is explanatory drawing which shows the directivity of the antenna of Fig.11 (a), (b). It is a perspective view which shows the modification of the antenna of Fig.1 (a). It is a figure which shows the antenna of the modification of the antenna of FIG. It is explanatory drawing of the antenna which outputs a horizontal knitting wave. It is explanatory drawing of an antenna without a radio wave insensitive direction. It is explanatory drawing of a subject. It is explanatory drawing of the antenna which connected the feed point. It is explanatory drawing of the antenna which improved the radio wave insensitive direction. It is explanatory drawing of the other antenna which improved the radio wave insensitive direction. It is a figure which shows the conventional dipole antenna. It is a figure which shows the VSWR characteristic of the antenna of Fig.22 (a)-(c).

Explanation of symbols

40, 50, 60, 70, 80, 90, 100 Antenna 41, 51, 61, 71, 81, 91, 101 Feed point 42, 52, 62, 72, 82, 92, 102 First transmission / reception unit 43, 53, 63, 73, 83, 93, 103 Second transmission / reception unit 44, 54, 64, 74, 84, 94, 104 Third transmission / reception unit 45, 55, 65, 75, 85, 95, 105 4 transmitter / receiver units 46, 56, 66, 76, 96 Fifth transmitter / receiver units 57, 67, 77 Sixth transmitter / receiver units 78, 86 Lids

Claims (10)

A first transmission / reception unit formed of a linear conductor having one end connected to a feeding point;
A linear second transmission / reception unit formed of a linear conductor having one end connected to the feeding point, and arranged symmetrically with the first transmission / reception unit across the feeding point;
It is formed of a conductor extending from the other end of the first transmission / reception unit, and is a linear third direction facing a second direction perpendicular to the first direction toward the first transmission / reception unit. A transmission / reception unit;
A linear fourth transmission / reception unit formed of a conductor extending from the other end of the second transmission / reception unit and facing the second direction;
A linear fifth transmission / reception unit formed of a conductor having one end connected in the vicinity of the feeding point of the first transmission / reception unit and facing the second direction;
A sixth transmission / reception unit formed of a linear conductor, one end connected to the tip of the third transmission / reception unit, and the other end connected to the other end of the fifth transmission / reception unit;
An antenna comprising: The antenna according to claim 1 , wherein a length of the third transmission / reception unit is equal to a length of the fifth transmission / reception unit. It is formed of a strip-shaped conductor having one side facing the first direction and the opposite side facing away from the one side by a predetermined distance in a second direction perpendicular to the first direction. A first transmission / reception unit connected to the point;
It is formed by a strip-shaped conductor having one side facing the first direction and the opposite side facing away from the one side by a predetermined distance in the second direction, and the one side is connected to the feeding point and the power feeding A second transmission / reception unit facing one side of the first transmission / reception unit across a point;
A third transmission / reception unit formed of a strip-shaped conductor and extending from the opposite side of the first transmission / reception unit in a third direction perpendicular to the first direction and the second direction;
A fourth transmission / reception unit formed of a strip-shaped conductor and extending in the third direction from the opposite side of the second transmission / reception unit ;
A fifth conductor which is formed of a strip-shaped conductor and protrudes in the third direction from the vicinity of the one side of the first transmission / reception unit and faces the third transmission / reception unit and the fourth transmission / reception unit. The transmitter / receiver of
Formed by a strip-shaped conductor having one side facing the first direction and the opposite side opposite to the one side, the opposite side is provided at the tip of the third transmitting / receiving unit extending from the first transmitting / receiving unit. A sixth transmission / reception unit having one side connected to the tip of the fifth transmission / reception unit projecting from the first transmission / reception unit;
An antenna comprising: The length of the third direction of the third transmission / reception unit extending from the first transmission / reception unit and the length of the fifth transmission / reception unit protruding from the first transmission / reception unit. The antenna according to claim 3 , wherein the length in the direction of 3 is equal. Supported by the first transmission / reception unit, the third transmission / reception unit, the fifth transmission / reception unit, and the sixth transmission / reception unit, the first transmission / reception unit, the third transmission / reception unit an antenna according to claim 3 or 4, characterized in that it comprises a lid member for the lid surrounded by space wave transceiver section of the wave transceiver unit and said sixth fifth. The feeding point, according to any one of claims 3 to 5, characterized in that it is connected to an end of the first side of one side and the second wave transceiver portion of the wave transceiver section antenna. A first transmission / reception formed of a strip-shaped conductor having one side facing the first direction and an opposite side opposite to the one side, the one side being connected to a feeding point and curved in a plane perpendicular to the one side Namibe,
It is formed of a strip-shaped conductor having one side facing the first direction and the opposite side opposite to the one side, and the one side is connected to the feeding point and is bent in the plane so that the inner peripheral surface is A second transmission / reception unit facing the inner peripheral surface of the first transmission / reception unit;
It is formed of a strip-shaped conductor, protrudes from the vicinity of one side of the first transmission / reception unit and faces the inner peripheral surface of the first transmission / reception unit, and the inner peripheral surface of the second transmission / reception unit A third transmission / reception unit facing
It is formed of a strip-shaped conductor having one side facing the first direction and the opposite side opposite to the one side, the one side is connected to the opposite side of the first transmission / reception unit, and the opposite side is the first transmission / reception unit A fourth transmission / reception unit connected to the tip of the third transmission / reception unit projecting from the wave unit;
An antenna comprising: The antenna according to claim 7 , wherein the first transmission / reception unit draws an arc having a central angle of 90 ° by the curvature. Supported by the first transmitting / receiving unit, the third transmitting / receiving unit, and the fourth transmitting / receiving unit, the first transmitting / receiving unit, the third transmitting / receiving unit, and the fourth transmitting / receiving unit. antenna according to claim 7 or 8, characterized in that it comprises a lid member for the lid in a space surrounded by. 10. The power feeding point according to claim 7, wherein the feeding point is connected to one side of the first transmission / reception unit and one end of the second transmission / reception unit. 11 . antenna.

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