JPH07112131B2 - Antenna device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an antenna device for transmitting and receiving a plurality of signals in a microwave band by using a microstrip resonator.

(Prior Art) In recent years, a system has been proposed in which a person or a moving object is provided with a response device, and information is exchanged by microwaves between the response device and a stationary interrogation device. If personal information or the like is written in the response device as data, the response device can function as a kind of ID card or pass permit in the information exchange with the interrogation device that manages the gate or the like. In addition, in a manufacturing process site where high-mix low-volume production is performed, a response device that writes specification data is attached to a semi-finished product in the production process, and an inquiry device fixed in each process inquires the response device for specifications. If the work according to is performed, it can be made to function as an electronic specification instruction sheet.

Here, it is inconvenient to supply driving power from a commercial AC power supply to a mobile phone or a mobile when the response device functions as the above-mentioned ID card or specification instruction sheet, and the power supply is independently secured as the response device. You may not get it. In particular, when it is used as an ID card or the like, it must be small and lightweight and have a long life, and a power source such as a battery cannot satisfy the life.

Therefore, Japanese Patent Laid-Open No. 51-35911, Japanese Patent Laid-Open No. 58-151722, Japanese Patent Laid-Open No. 58-85183, etc. propose communication systems that do not require a battery as a power source for a response device. FIG. 5 is a block circuit diagram showing an outline of an example of a conventional communication system.

In FIG. 5, the interrogator 1 includes a first oscillator circuit 2 that oscillates a _first frequency f ₁ (for example, 2440 MHz) in the microwave band, and a second oscillator circuit 2 that slightly differs from the _first frequency f ₁ in frequency.
And a second oscillator circuit 3 that oscillates the frequency f ₁ (for example, 2455 MHz). The first frequency f ₁ output from the first oscillating circuit 2 is amplified by the amplifier 4 and remains unmodulated, and the energy wave having the first frequency f ₁ as a carrier wave from the antenna 5 by vertical polarization, for example. Is transmitted to the response device 6. Further, the second frequency f ₂ output from the second oscillator circuit 3 is amplitude-modulated by the interrogation signal in the modulator circuit 7, further amplified by the amplifier 8, and then the second frequency f ₂ is horizontally polarized by the antenna 9. It is transmitted to the response device 6 as an interrogation signal wave having ₂ as a carrier wave. Then, the interrogator 1 receives the first frequency f ₁ transmitted from the responder 6.
An antenna 10 is provided for receiving a response signal wave having the second harmonic wave 2f ₁ as a carrier wave. A demodulation response signal is demodulated from the response signal wave received by the antenna 10 through the band pass filter 11, the low noise block down converter 12, and the like. It should be noted that the interrogation apparatus 1 has a microprocessor (not shown) built therein, and identifies whether or not the malfunction response signal received and demodulated is appropriate for the interrogation signal, or responds to this demodulation response signal. The operation signal for performing the above process is output.

The response device 6 is provided with an antenna 13 for receiving the energy wave transmitted from the antenna 5, and the energy wave received by the antenna 13 is converted to DC power + B through a rectifier circuit 14 and a low-pass filter 15. To be done. This DC power is used as a drive power source for the response device 6. Further, the energy wave received by the antenna 13 is converted into the second harmonic wave 2f ₁ by the multiplication circuit 16 such as a diode, and is given to the modulation circuit 18 via the bandpass filter 17 as a carrier wave of the response signal wave. The second harmonic 2f ₁ is amplitude-modulated by the response signal in the modulation circuit 18, and is transmitted from the antenna 19 to the interrogation apparatus 1 as a response signal wave. In addition, the response device 6 is an antenna for receiving the interrogation signal wave transmitted from the antenna 9.
20 is provided, and the demodulation interrogation signal is demodulated from the interrogation signal wave received by the antenna 20 through the detection circuit 21 and the low-frequency blocking filter 22. It should be noted that the response device 6 contains a microprocessor or the like (not shown), stores appropriate information, and outputs an appropriate response signal in accordance with the demodulated interrogation signal.

By the way, in the interrogation apparatus 1 described above, the response apparatus 6
In order to ensure reliable operation even at a long distance, we want to increase the transmission power of energy waves. Therefore, in the conventional interrogation apparatus 1, for example, the attenuators 5, 9 and 10 are formed as follows on a dielectric band substrate having a low dielectric constant (eg, ε = 10). That is, the plurality of microstrip resonators having the resonance frequency of the first frequency f ₁ are arranged on the dielectric substrate, and the antenna 5 is formed by the array antenna in which these are connected by the feeder line. Further, the microphone strip resonator having the second frequency f ₂ disposed on the side of the antenna 5 on the same surface of the same dielectric substrate as the resonance frequency is used for the attenuator 9.
Further, the antenna 10 is formed by the microstrip resonator having the second harmonic 2f ₁ as the resonance frequency, which is disposed on the side of the antenna 5 on the same surface of the same dielectric substrate. In particular, the antenna 5 is configured so that the antenna gain is increased by the array antenna.

(Problems to be Solved by the Invention) In the conventional antenna device of the interrogation device 1 described above,
Energy waves can be transmitted to the response device 6 with a large amount of power,
Due to the following reasons, the communicable distance cannot be sufficiently increased.

That is, since the antennas 5, 9, 10 are arranged side by side on the same surface of the dielectric substrate, the central axes of the main beams of the antennas 5, 9, 10 are laterally displaced. Therefore, if the antenna 13 of the response device 6 is arranged on the central axis of the main beam of the antenna 5 in order to strongly receive the energy wave, the response device 6 can receive a large amount of power, but the response device 6 has a small space. The arranged antennas 19, 20 are the other antennas 9, 1 of the interrogation apparatus 1.
It deviates from the center axis of the main beam of 0. For this,
The answering device 6 cannot strongly receive the inquiry signal, and the inquiry device 6 cannot strongly receive the answering signal. This is because the communicable distance does not become long due to the above reason especially when the directivity of the main beam is strong.

The present invention has been made in view of the circumstances of the conventional antenna device as described above, and it is possible to efficiently transmit and receive a plurality of signals by arranging the plurality of antennas so that the central axes of the main beams coincide with each other. It is an object of the present invention to provide an antenna device capable of performing the above.

(Means for Solving the Problems) In order to achieve such an object, the antenna device of the present invention has a front surface of a dielectric substrate on which a ground plate is arranged.
A plurality of first microstrip resonators are arranged at equal intervals so as to surround a central empty space, and the plurality of first microstrip resonators are connected by a feeder line to form an array antenna. One second microstrip resonator is arranged at the center of an empty space surrounded by the plurality of first microstrip resonators on the same surface of the dielectric substrate. The array antenna may radiate a circularly polarized wave, and the second microstrip resonator may be a circularly polarized antenna that receives a circularly polarized wave that rotates in a direction opposite to the circularly polarized wave.

Further, in the antenna device of the present invention, a plurality of first microstrip resonators are arranged at equal intervals so as to surround a central empty space on the front surface of a dielectric substrate having a back surface provided with a ground plate. A plurality of first microstrip resonators are connected by a feed line to form a first array antenna, and the first microstrip resonators are arranged on the same surface of the dielectric substrate except where the first microstrip resonators are arranged. Two second microstrip resonators are respectively arranged in point symmetry with respect to the center of the empty space, and these two second microstrip resonators are connected to each other by a feeder line to form a second
May be configured to form the array antenna.

(Operation) Since one second microstrip resonator is arranged at the center of the empty space surrounded by the array antenna formed by the plurality of first microstrip resonators, the array antenna and the second microstrip resonator are arranged. The central axes of the main beams of the resonator coincide. By arranging this second microstrip resonator, the characteristics of the array antenna formed by the plurality of first microstrip resonators do not change. When the circular polarized wave radiated from the array antenna is used as the circular polarized wave antenna which receives the circular polarized wave rotating in the opposite direction to the second microstrip resonator, the signal radiated from the array antenna is It is not absorbed by the second microstrip resonator.

In addition, the center of the empty space surrounded by the first array attenuator formed by the plurality of first microstrip resonators and the second array antenna formed by the two second microstrip resonators are point-symmetrical. If the centers are matched, the central axes of the main beams of the first and second array antennas match.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a plan view of an embodiment of the antenna device of the present invention, FIG. 2 is a partial side view showing the laminated structure of FIG. 1, and FIG. 3 is a view of the antenna device of FIG. FIG. 4 is a diagram showing directional characteristics of each antenna, and FIG. 4 is a block circuit diagram showing an outline of an example of a communication system to which the antenna device of the present invention is applied.

First, an example of a communication system to which the antenna device of the present invention is applied will be described with reference to FIG.

In FIG. 4, in the interrogator 30, the first frequency f ₁ output from the first oscillator circuit 2 is amplified by the amplifier 4 and given to the hybrid link 31.
At 31, it is converted into two signals with 90 ° different phases. Then, a circularly polarized wave is generated by these two signals, and is transmitted from the circularly polarized wave antenna 32 to the responding device 40 as an energy wave by, for example, left-handed circularly polarized wave without being modulated. Further, the second frequency f ₂ output from the second oscillator circuit 3 is amplitude-modulated by the interrogation signal in the modulator circuit 7, further amplified by the amplifier 8 and given to the hybrid link 31. Are converted into two signals. Then, a circularly polarized wave is generated by these two signals, and the circularly polarized antenna 32 produces a right-handed circularly polarized wave.
It is transmitted to the response device 40 as an interrogation signal wave. In the hybrid link 31, the isolation between the first and second frequencies f ₁ and f ₂ is good, and they do not influence or mix with each other.

In addition, the interrogator 30 receives the first message transmitted from the responder 40.
An antenna 33 is provided for receiving a response signal wave whose frequency f ₁ is phase-modulated by the response signal. In the response signal wave received by the antenna 33, only the component of the first frequency f ₁ is extracted by the bandpass filter 34 and the homodyne detection circuit 35.
Given to. The homodyne detection circuit 35 receives the first frequency f ₁ from the first oscillator circuit 2 as a detection carrier wave, and the response signal wave is homodyne detected and demodulated as a first demodulation response signal.

Further, in the interrogation device 30, when the response device 40 phase-modulates the _first frequency f ₁ , a harmonic component such as an amplitude-modulated response signal is generated, and an antenna for receiving this harmonic signal wave is generated. Ten are provided. This antenna
From the harmonic signal wave received at 10, only the second harmonic component is extracted by the band-pass filter 11, and is further passed through the low noise block down converter 12 and the detection circuit 36 to the second harmonic component.
It is demodulated as a demodulation response signal. Further, the first demodulation response signal and the second demodulation response signal are compared by a microprocessor (not shown), and if they match, it is confirmed that the signal is accurately demodulated in the response without being affected by fading or noise. You can

The response device 40 is provided with a circular polarization antenna 41 having a band capable of receiving both the energy wave and the interrogation signal wave transmitted from the circular polarization attenuator 32. And this circular polarization antenna 41
Both the energy wave and the interrogation signal received by the rectifier circuit
It is rectified at 42. Further, a DC component is extracted from this rectified output through a low pass filter 43, and this DC power +
B is used as a driving power source for the response device 40. Further, a signal component is extracted from the rectified output through the low-frequency blocking filter 44 and appropriately processed as a demodulation interrogation signal by a microprocessor or the like (not shown).

Further, the response device 40 is additionally provided with an antenna 45 for receiving the energy wave transmitted from the circularly polarized antenna 32 of the interrogation device 30. The energy wave as a carrier for the response signal wave received by the antenna 45 is given to the phase modulation circuit 46, phase-modulated by the response signal output from the microprocessor distant, and a response is again sent from the antenna 45 toward the interrogation device 30. It is transmitted as a signal wave. This phase modulation circuit
Upon modulation by 46, a harmonic component, such as amplitude-modulated response signal, is generated, and this is simultaneously radiated from the antenna 45 as a harmonic signal wave.

Next, the antenna device of the present invention comprising the circularly polarized antenna 32 and the antennas 33, 10 of the interrogation device 30 in FIG. 4 will be described with reference to FIGS. On the surface of the first dielectric substrate 50, the wavelength λ of the energy wave transmitted by the left-hand circularly polarized wave
₁ and square microstrip resonators 51, 51 ... Each having a half of the average value of the wavelength λ ₂ of the interrogation signal wave transmitted by right-handed circular polarization surrounds the central empty space at equal intervals. Are arranged like this. As shown in FIG. 2, a ground plate 52 made of a conductive metal such as aluminum is laminated on the back surface of the first dielectric substrate 50, and the second dielectric substrate is attached to the ground plate 52. 53 is directly stacked. On the surface of the second dielectric substrate 53, four hybrid links 31, 31, ... And microstrip lines 55, 55 ... Further, the two terminals of the hybrid links 31, 31 ... And the microstrip resonators 51, 51.
The dielectric substrates 50, 53 and the ground plate 52 are connected by soldering both ends of the conduction pins 56, 56.

Here, the hybrid link 31, 31 includes a wavelength lambda ₁ of the energy waves are formed by boxes shaped microstrip line square quadrilateral 1/4 one side of the mean value of the wavelength lambda ₂ of the interrogation signal wave It Then, the input / output terminal 57 to which the energy wave is applied from the amplifier 4 via the connector (not shown)
The microstrip line 55 is branched into two, the branch destinations of which are further branched into two, and these four branch destinations are the terminals a, a of the four hybrid links 31, 31 ...
Are connected so that all signal waveforms have the same phase.
Further, the input / output terminal 58 to which the interrogation signal wave is given from the amplifier 8 via the connector (not shown) is branched into four by the microstrip line 55, and the above-mentioned terminal a of the four hybrid links 31, 31 ... , a ... and Terminals b, b ... Adjacent to them are all connected so that the signal waveforms have the same phase. further,
The other two terminals c, c ..., d, d of the hybrid link 31,31 ...
Is about 1/3 from the center of the adjacent two sides of the microstrip resonators 51, 51 to the inside of the resonator via the conduction pins 56, 56.
It is connected so that offset power may be supplied only to the point.

Further, for the right-handed circularly polarized wave having one side of 1/2 of the wavelength λ ₁ of the energy wave in the center of the empty space surrounded by the microstrip resonators 51, 51, on the surface of the first dielectric substrate 50. Of 1
One microstrip resonator 59 formed in the point-fed rectangular circularly polarized antenna is arranged. Then, on the surface of the first dielectric substrate 50, a microstrip line 60 as a power supply line is connected to one side of the microstrip resonator 59, and its end 61 is a bandpass filter via a connector (not shown). Connected to 34.

Further, on the surface of the first dielectric substrate 50, two square microstrip resonators 62, 62 each having 1/4 of the wavelength λ ₁ of the energy wave as one side are provided.
Are arranged point-symmetrically with respect to the center of the plurality of positions where the ... Is arranged. Then, microstrip lines 63, 63 are connected to one side of these microstrip resonators 62, 62 as power supply lines on the surface of the first dielectric substrate 50, respectively, and a signal of the second harmonic component 2f ₁ of the energy wave is generated. It is connected to the input / output terminal 64 so that the waveforms are combined in phase, and further connected to the bandpass filter 11 via a connector (not shown).

In such a configuration, the energy wave applied to the input / output terminal 57 is output at the hybrid links 31, 31, ... With the phase of the signals at the terminals c, c ... Delayed by 90 degrees with respect to the signals at the terminals d, d. To be done. Therefore, the micro-Slorip resonator 51,51…
The left-hand circularly polarized wave of the energy wave is transmitted from the back side of the paper in FIG. In addition, hybrid link 31,3
Energy waves are not output to terminals 1 ...

Further, the interrogation signal wave given to the input / output terminal 58 is a terminal for the signals of the terminals c, c ... at the hybrid links 31, 31 ,.
The signals of d, d ... Are output with a phase delay of 90 degrees. Therefore, the right-handed circularly polarized wave of the interrogation signal wave is transmitted from the back side of the paper surface to the front side in FIG. 1 from the microstrip resonators 51, 51. The interrogation signal wave is the hybrid link 31,31.
... is not output to the terminal a.

Then, from the first array antenna formed by the microstrip resonators 51, 51, ..., As shown in FIG. 3, the main beam with the center of the plurality of positions where the microstrip resonators 51, 51. 70 is generated perpendicular to the surface of the first dielectric substrate 50. Similarly, a main beam 71 having its central axis aligned with the main beam 70 of the first array antenna is also generated in the microstrip resonator 59 arranged in the central air space at a plurality of positions. Further, the main beam 72 with its central axes aligned is also generated from the second array antenna formed by the microstrip resonators 62, 62 arranged point-symmetrically with respect to the centers of the plurality of positions. Therefore, the circular polarization antenna 32 formed by the four microstrip resonators 51, 51 ..., the antenna 33 formed by the microstrip resonator 59, and the antenna formed by the two microstrip resonators 62, 62 All of 10 have the highest antenna gain on the same axis. Therefore, the response device
When 40 is associated with the central axis of the first array antenna, both signals can be transmitted and received most efficiently, and the communicable distance can be extended correspondingly. Since the microstrip resonator 59 is arranged in the empty space at the center of the first array antenna, the arrangement of the microstrip resonator 59 does not change the characteristics of the first array antenna.

Since the microstrip resonator 59 is formed in the antenna for right-handed circularly polarized wave, it absorbs the left-handed circularly polarized energy wave radiated from the microstrip resonators 51, 51 ... Questioning device 30
Energy waves are transmitted with a large electric power.

Further, since the second dielectric substrate plate 53 is directly laminated on the ground plate 52, the microstrip resonators 51, 51
…, 59, 62, 62 and hybrid link 31, 31,… etc.,
One ground plate 52 can be shared. In addition, the conduction pins 56 and 56 are compared with the one in which two ground plates are arranged on the first and second dielectric substrates 50 and 53, respectively.
There is little signal leakage due to ... This is because when two ground plates are overlapped with each other, a gap is slightly formed between the two ground plates, and this gap acts as a waveguide.
Therefore, the signals radiated from the conduction pins 56, 56 ... Are likely to leak through this gap. However, with one sheet, such action does not occur.

In the above embodiment, the energy wave and the inquiry signal wave are
The microstrip resonators 51, 51 forming the first array antenna respectively transmit left-handed circular polarization and right-handed circular polarization, but the present invention is not limited to this, and vertical polarization and horizontal polarization are used. Of course, you may send it.

(Effects of the Invention) Since the antenna device of the present invention is configured as described above, it has the following excellent effects.

In the antenna device according to claim 1, a plurality of first
Since the central axes of the main beams of the first array antenna formed of the microstrip resonator of and the antenna formed of the second microstrip resonator coincide with each other, the central axis of the main beam is the same for both antennas. The gain is high. Therefore, if the response device is arranged on this central axis, both signals can be transmitted and received most efficiently,
The communication distance can be extended by that much. Moreover, since the second microstrip resonator is provided in the empty space in the center of the first array antenna, the arrangement of the second microstrip resonator does not change the characteristics of the first array antenna, and the design is easy. Is. Then, even if two antennas are arranged adjacent to each other, if one antenna radiates circularly polarized waves and the other antenna is a circularly polarized antenna that rotates in the opposite direction, one antenna There is no problem that the radiated signal is absorbed by the other antenna.

Further, even if both of the two antennas are array antennas, if the centers of the plurality of positions where the plurality of microstrip resonators forming the first and second array antennas are arranged coincide with each other, the center of the main beam The axes also match and the communication distance can be extended.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the antenna device of the present invention, FIG. 2 is a partial side view showing the laminated structure of FIG. 1, and FIG. 3 is an antenna device of FIG. FIG. 4 is a diagram showing the directional characteristics of each antenna in FIG. 4, FIG. 4 is a block circuit diagram showing an outline of an example of a communication system to which the antenna device of the present invention is applied, and FIG. 5 is a conventional communication system. It is a block circuit diagram which shows the outline of an example. 50: first low dielectric substrate, 51, 59, 62: microstrip resonator, 52: ground plate, 55, 60, 63: microstrip line.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikazu Kawashima 1-12-2 Kawana, Fujisawa-shi, Kanagawa Yamatake Honeywell Co., Ltd. Fujisawa Plant (72) Hiroaki Furushima 1-2-2 Kawana, Fujisawa-Kanagawa Yamatake Honeywell Co., Ltd. Fujisawa Plant (56) Reference JP 62-210703 (JP, A) JP 61-177004 (JP, A) JP 62-176307 (JP, A) JP 62- 49711 (JP, A) JP-A-63-151102 (JP, A) US Patent 4060810 (US, A)

Claims (3)

[Claims] 1. A plurality of first microstrip resonators are arranged at equal intervals so as to surround a central empty space on a front surface of a dielectric substrate having a ground plate on the back surface. One microstrip resonator is connected by a feed line to form an array antenna, and a second microstrip is formed at the center of an empty space surrounded by the plurality of first microstrip resonators on the same surface of the dielectric substrate. An antenna device comprising one strip resonator. 2. The Athena device according to claim 1, wherein the array antenna radiates a circularly polarized wave, and the second microstrip resonator receives a circularly polarized wave rotating in a direction opposite to the circularly polarized wave. An antenna device characterized by being a circularly polarized antenna. 3. A plurality of first microstrip resonators are arranged at equal intervals so as to surround a central air space on a front surface of a dielectric substrate having a ground plate on the back surface, and a plurality of these first microstrip resonators are arranged. One microstrip resonator is connected by a power supply line to form a first array antenna, and the empty space is provided at a position other than the position where the first microstrip resonator is arranged on the same surface of the dielectric substrate. Two second microstrip resonators are respectively arranged in point symmetry with respect to the center, and these two second microstrip resonators are connected by a feed line to form a second array antenna. An antenna device characterized by the above.