JP3832069B2 - Antenna device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna device, and more particularly to an antenna device that is reduced in size and facilitates assembly.
[0002]
[Prior art]
The prior art will be described with reference to FIG. FIG. 4 shows a linearly polarized loop antenna 1. Both ends of the square loop element 2 are connected to a balanced line connection terminal of a balanced / unbalanced conversion and impedance conversion circuit 4 through a balanced feed line 3, and the other unbalanced line is connected. A connection terminal and an RF circuit (not shown) for reception or transmission are connected by a coaxial cable 5. As shown in the figure, when a feed point is provided in the horizontal element part of the loop element 2, the antenna becomes a horizontally polarized wave, and if the feed point is positioned at the vertical element part by being rotated 90 ° from the posture of the figure. This is a vertically polarized antenna.
[0003]
Although not shown, if a perturbation element is provided in the loop element 2, a circularly polarized loop antenna is obtained.
[0004]
[Problems to be solved by the invention]
Since the conventional antenna device requires balanced / unbalanced conversion and impedance conversion circuits, there are problems that the number of parts and assembly man-hours are large, the cost increases, and the external dimensions increase. Therefore, technical problems to be solved in order to reduce the number of parts and assembly man-hours of the antenna device and to reduce the size thereof arise, and the present invention aims to solve the above problems.
[0005]
[Means for Solving the Problems]
The present invention is proposed to achieve the above object. A loop element is arranged in parallel to the ground plane on the ground plane, and a feeding conductor is arranged between the ground plane and the loop element. A loop antenna that feeds power to a loop element by electromagnetic coupling, wherein a feed conductor support is installed on a ground plane, a loop element having a circumference of 1 wavelength is disposed above the feed conductor support, and the feed conductor support is a feed conductor having a length of 1/4 wavelength and positioned parallel to the circumferential direction of the loop element, the and the formed groove or recess so as not to protrude the feed conductor onto the top surface of the feed conductor support table An antenna device comprising: a dielectric spacer stacked on the power supply conductor support ; and a loop element mounted on the dielectric spacer. An antenna device is provided.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an antenna device 11 in which a feeder conductor support base 13 and a dielectric spacer 14 are laminated on a double-sided printed wiring board 12 whose upper surface is an entire ground plane 12 a, and a rectangular loop element 15 is placed on the dielectric spacer 14. Is provided. An RF circuit pattern 12b is printed on the lower surface of the double-sided printed wiring board 12, and various electronic components (not shown) are mounted on the RF circuit pattern 12b to form an RF circuit.
[0007]
Feeding conductors 16 and 17 which are inverted L-shaped radiating elements supported by the feeding conductor support 13 are arranged in parallel with the element arrangement direction of the loop element 15, and portions 16 a and 17 a bent vertically downward are feed conductors. The through holes 18 and 19 of the support base 13 and the through holes 20 and 21 which are non-through holes provided in the double-sided printed wiring board 12 are penetrated to the back surface and connected to the antenna switching circuit on the back surface. The loop element 15 is fed by electromagnetic coupling from the feed conductor 16 or 17 and receives or transmits a radio frequency via the loop element 15.
[0008]
As shown in FIG. 2, recesses 22 and 23 or grooves for positioning the power supply conductors 16 and 17 are formed on the peripheral edge portion of the upper surface of the power supply conductor support 13 that is an insulator such as resin. If the vertical portions of the conductors 16 and 17 are inserted into the through holes 18 and 19 provided in the recesses 22 and 23, the feed conductors 16 and 17 are positioned so as to be parallel to the loop element 15, and the feed conductors 16 and 17. Does not protrude beyond the upper surface of the feed conductor support 13.
[0009]
As shown in FIG. 1, a dielectric spacer 14 such as a polymer synthetic resin or ceramic is adhered to the upper surface of the power supply conductor support 13 on which the power supply conductors 16 and 17 are mounted. A square loop element 15 is provided by printing or gluing. The loop element 15 has a perimeter length C (about one wavelength), and perturbation element portions 15a and 15b for generating circularly polarized waves are provided at one corner and the corner opposite to the corner. The perturbation element portions 15 a and 15 b are located at + 45 ° and −135 ° from the feeding point of the horizontal feeding conductor 16 as viewed from the front of the loop element, and are located at −45 ° and + 135 ° from the vertical feeding conductor 17.
[0010]
FIG. 3 shows the spatial positional relationship between the loop element 15, the power supply conductors 16 and 17, and the ground plane 12a. As an example of the dimensions of each part, the peripheral length C of the square loop element 12 and the elements of the perturbation element parts 14a and 14b are shown. The length ΔL, the height h of the loop element 15 from the ground plane 15a, and the length LV + LH of the L-shaped feed conductor 13 are C = 1.032λ _1.472 , ΔL = 0.029λ _1.472 , h = 0.0491λ _1.472 , LV = 0.014λ _1.472 and LH = 0.236λ _1.472 . However, λ _1.472 is a free space wavelength at a design frequency of 1.472 GHz.
[0011]
In the antenna device 11, if power is fed from the horizontal feed conductor 16, right-handed circularly polarized waves are radiated from the loop element 15 in the + Z direction by the perturbing element portions 15 a and 15 b. Further, if power is supplied from the vertical power supply conductor 17, a left-handed circularly polarized wave is radiated from the loop element 15 in the + Z direction. Therefore, by switching the horizontal feed conductor 16 and the vertical feed conductor 17, it is possible to transmit and receive left-hand circularly polarized waves and right-handed circularly polarized waves.
[0012]
Although illustration is omitted, if the perturbation element portions 15a and 15b are removed from the loop element 15, a linearly polarized loop antenna capable of transmitting and receiving by switching between horizontal polarization and vertical polarization is obtained.
[0013]
In this way, the feed conductors 16 and 17 are arranged between the ground plane 12a and the loop element 15, and power is fed from the feed conductors 16 and 17 to the loop element 15 by electromagnetic coupling, so that a balanced / unbalanced conversion circuit is unnecessary. Thus, since the dielectric spacer 14 is interposed between the power supply conductors 16 and 17 and the loop element 15, it can be formed smaller than when the loop element is disposed in the air.
[0014]
The present invention is not limited to the above-described embodiment, and various modifications are possible within the technical scope of the present invention, and it is natural that the present invention extends to those modifications.
[0015]
【The invention's effect】
As described above, the loop antenna according to the present invention has a configuration in which a feeding conductor having a length of 1/4 wavelength is arranged below and parallel to the circumferential direction of a 1- wavelength loop element in the zenith direction. The gain can be increased and a high sensitivity antenna can be realized. In addition, since the base that supports the power supply conductor on the ground plane includes a groove or a recess for positioning the power supply conductor at a predetermined position, the assembly of the power supply conductor is facilitated, and the number of assembly steps can be reduced.
[Brief description of the drawings]
1A and 1B show an antenna device of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a side view.
2A and 2B show a power supply conductor support, in which FIG. 2A is a plan view and FIG. 2B is a side cross-sectional view.
FIG. 3 is a diagram illustrating the configuration of the antenna device of FIG. 1;
FIG. 4 is a front view of a linearly polarized loop antenna showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Antenna apparatus 12 Double-sided printed wiring board 12a Ground plane 12b RF circuit pattern 13 Feeding conductor support stand 14 Dielectric spacer 15 Loop element 15a, 15b Perturbation element part 16, 17 Feeding conductor 18, 19 Through hole 20, 21 Through hole 22, 23 recess

Claims (2)

A loop antenna in which a loop element is arranged on the ground plane in parallel with the ground plane, a feeding conductor is arranged between the ground plane and the loop element, and power is fed from the feeding conductor to the loop element by electromagnetic coupling,
A feed conductor support base is installed on the ground plane, a loop element having a circumference of 1 wavelength is disposed above the feed conductor support base, and the feed conductor support base includes a feed conductor having a length of 1/4 wavelength. An antenna device comprising: a groove or a recess that is positioned in parallel along the circumferential direction of the loop element and that is formed so that the feed conductor does not protrude above the upper surface of the feed conductor support base . The antenna device according to claim 1 , wherein a dielectric spacer is laminated on the feed conductor support and a loop element is mounted on the dielectric spacer .

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