JP2008177956A - Communication base station and communication system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication base station capable of increasing a distance between a base station and an object or a terminal station, and to provide a communication system using the communication base station. <P>SOLUTION: A direction division double base station has a transmission circuit 1, an antenna 8, a reception circuit 2, and a circulator. The transmission circuit 1 is connected to two circulators 4, 5 via a first hybrid coupler 3 distributing each transmission wave to two waves. The antenna 8 is connected to other ports of the two circulators 4, 5 via a second hybrid coupler 6 coupling the two distributed transmission waves and demultiplexing a reception wave to two waves. The reception circuit 2 is further connected to other ports of the two circulators 4, 5 via a third hybrid coupler 7 coupling the two distributed reception waves. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, an electromagnetic wave radiated from a communication base station such as a radar or RF-ID (Radio Frequency Identification) is scattered by an unspecified object or a terminal station and arrives at the base station again. The present invention relates to a communication base station that a station receives and identifies unspecified objects or information unique to a terminal station, and a communication system using the same.

  The technology for remotely identifying an unspecified number of objects is expected to be useful in abundance in recent years as the quantity of physical distribution increases and the distribution speed increases. In order to identify objects in such a large amount and at high speed, it is indispensable to apply information transmission means that infiltrate the objects because the positional relationship between these objects cannot be specified. Wireless technology is suitable for such applications, and in particular, a system for detecting an object using electromagnetic waves and a system for transmitting information held by the object have already been realized, for example, as a radar system or a wireless tag system. I am serving.

  However, with the increase in logistics speed and capacity, it has become a universal social requirement to improve the ability of object detection and information transmission using electromagnetic waves, in other words, the distance that electromagnetic waves can reach in the system. Yes. The electromagnetic wave attenuates in proportion to the distance to the power of 2 to 3 along with the transmission distance. Therefore, when the transmission distance of the electromagnetic wave increases, when the electromagnetic wave radiated from the base station arrives at the base station again, its power decreases remarkably. Therefore, it is extremely resistant to various disturbance factors. In such a system, in order to re-radiate the energy of the electromagnetic wave arriving from the base station to the base station with as little conversion loss as possible, generally a method of using the scattered electromagnetic field itself from the object to be identified as a carrier wave for information transmission Is common. In order to generate a new carrier wave by some means, it is necessary to convert the high-frequency power of the electromagnetic wave into power supply power for some means, and in that case, a conversion loss always occurs in reality. In wireless transmission using electromagnetic waves, the reach of electromagnetic waves is limited by the power to be applied to the carrier, so maximizing the power efficiency of carrier generation is the reach of electromagnetic waves in the system, in other words, the application limit of the system Leads to maximizing

  In a system that uses scattered waves directly as a carrier wave, the transmission power itself radiated from the base station is the largest disturbance factor of the electromagnetic waves that re-enter the base station. This is because the disturbance factor cannot be removed using a general-purpose technique such as a filter because the frequencies of both are the same. In general, in a radio communication system, a frequency division duplex (Frequency Divide Duplex: FDD) or a time division duplex (Time Divide Duplex: TDD) is used to duplex a transmission wave and a reception wave (duplex). A technique called reception and transmission at different frequencies or different time timings, which is equivalently duplexed between a transmission wave and a reception wave, is used. In the case of using a scattered wave directly as a carrier wave, a conventional technique that can be called direction division duplex (DDD) is known. In this technique, a circulator is used to exit from a base station. The transmission wave and the reception wave are equivalently duplicated by using the difference in directionality between the electromagnetic wave and the electromagnetic wave entering the base station (see, for example, Non-Patent Document 1).

  FIG. 10 is a circuit diagram showing a configuration of a conventional communication base station. As shown in FIG. 10, the communication base station includes a carrier wave generator 61 that is a source of electromagnetic waves, an antenna 68 that radiates the electromagnetic waves to the outside (for example, toward the terminal station), and a received wave at the antenna 68. A receiving circuit 62 for receiving, a carrier wave generator 61, an antenna 68, and a circulator 64 for connecting the receiving circuit 62 are provided.

  In the communication base station of FIG. 10, a circulator 64 is used as a directional coupler, and an electromagnetic wave generated by the carrier wave generator 61 is radiated from an antenna 68 via the circulator 64. The electromagnetic wave rearriving at the base station is guided from the antenna 68 to the circulator 64 and is transmitted not to the carrier wave generator 61 but to the receiving circuit 62 due to the nonreciprocity of the circulator 64.

JP 2006-203469 A Klaus Finkenzellar, Translated by Software Engineering Laboratory "RFID Handbook 2nd Edition", May 2004, Nikkan Kogyo Shimbun, p. 45

  However, according to the conventional communication base station, in the circulator 64, electromagnetic energy wraparound in the reverse rotation direction, which cannot be generated in principle, actually occurs at about -20 to -30 dB. On the other hand, as the distance between the base station and the target object or between the base station and the terminal station increases, the electromagnetic wave re-arriving at the base station attenuates in proportion to the power of the distance to the second to third power and becomes weak. There is a problem that the degree of transmission wave (noise) from the device 61 to the receiving circuit 62 via the circulator 64 increases, and the distance between the base station and the target object or the base station and the terminal station cannot be increased. there were.

  Therefore, the object of the present invention is to solve the above-mentioned problems and suppress that the electromagnetic wave itself generated at the base station becomes a disturbance to the electromagnetic wave re-arriving at the base station. As a result, the base station and the target object or the terminal station It is an object of the present invention to provide a communication base station that makes it possible to increase a distance and a communication system using the same.

In order to achieve the above object, the present invention provides a transmission circuit for generating a transmission wave, an antenna for radiating the transmission wave to the outside and receiving a reception wave from the outside, and a reception wave received by the antenna. In a direction division duplex base station comprising a receiving circuit for receiving, and a circulator for transmitting the transmitted wave to the antenna and transmitting the received wave to the receiving circuit,
The transmission circuit is connected to two circulators via a first coupler that distributes the transmission wave in two, and the antenna combines the transmission wave distributed in two and the reception wave into two. The receiver circuit is connected to the other port of the two circulators via a second coupler that splits the signal into two, and the receiver circuit passes the third coupler that combines the received waves distributed in two. The communication base station is connected to another port of two circulators.

  Specifically, the transmission circuit is coupled to the port 1 of the first 90 ° hybrid coupler 3, the port 2 of the first 90 ° hybrid coupler 3 is terminated with a resistor, and the first 90 ° hybrid coupler 3 Ports 3 and 4 are connected to port 1 of the first and second circulators, respectively, and port 2 of the first and second circulators are connected to port 1 and port 2 of the second 90 ° hybrid coupler 6, respectively. Is coupled, an antenna is coupled to the port 3 of the second 90 ° hybrid coupler 6, and the port 4 of the second 90 ° hybrid coupler 6 is terminated with a resistor, and the first and second circulators Port 3 is connected to port 1 and port 2 of the third 90 ° hybrid coupler 7 respectively, and port 3 of the third 90 ° hybrid coupler 7 is connected to the resistor. The reception circuit is coupled to the port 4 of the third 90 ° hybrid coupler 7.

  The transmission circuit may be a carrier wave generation circuit.

  The received wave may be amplitude-modulated.

  The carrier wave frequency of the transmission wave and the reception wave may be the same.

  The antenna may be a linearly polarized antenna.

  The antenna may be a circularly polarized antenna.

  The first 90 ° hybrid coupler 3, the second 90 ° hybrid coupler 6, the first circulator and the second circulator are mounted on the surface of the substrate, and the third 90 ° hybrid coupler 7 is You may mount on the back surface of a board | substrate.

  Further, the substrate may be a multilayer substrate having an inner layer, and a ground layer on which the first, second and third 90 ° hybrid couplers are grounded may be formed on the inner layer of the multilayer substrate.

  Further, the present invention is a communication system including the communication base station and a plurality of terminal stations provided with a modulation means for switching an antenna and an input impedance of the antenna.

  The terminal station includes a rectifier circuit, a microcontroller, a storage circuit, and a changeover switch, supplies energy of electromagnetic waves input from the antenna of the terminal station to the microcontroller through the rectifier circuit, and stores the memory in the microcontroller. The input impedance of the antenna may be switched by turning on / off the switch according to a certain rule based on information stored in the circuit.

  The polarization format of the base station antenna and the polarization format of the terminal station antenna may be the same.

  According to the above configuration, the output of the transmission circuit that generates the electromagnetic wave radiated from the base station is divided into two by the first 90 ° hybrid coupler 3, and the circulator is coupled to each distribution output, and the forward rotation direction of each circulator The output is synthesized using the second 90 ° hybrid coupler 6 and supplied to the antenna, and the re-arrival electromagnetic wave input to the base station from the antenna is extracted from the forward rotation direction output of each circulator, and the third 90 ° This can be achieved by combining with the hybrid coupler 7 and transmitting it to the receiving circuit.

  The electromagnetic wave output from the transmission circuit is divided into two by the first 90 ° hybrid coupler 3, but they are synthesized in phase by the two circulators and the second 90 ° hybrid coupler 6, and are almost lost to the external space from the antenna. Radiated. Actually, loss is caused by copper loss, iron loss, radiation loss, etc. of each element, but it is about -1 dB or less, which is not a problem in practice. On the other hand, the electromagnetic wave input from the antenna is divided into two by the second 90 ° hybrid coupler 6, but they are synthesized in phase by the two circulators and the second 90 ° hybrid coupler 6, and are almost lost without loss. Communicated. On the other hand, the electric power of the electromagnetic wave that has been divided into two by the first 90 ° hybrid coupler 3 and leaked in the reverse rotation direction of the circulator is reversed by the third 90 ° hybrid coupler 7. Phase synthesis is almost impossible to reach the receiving circuit.

  Therefore, according to the present invention, while realizing the direction division duplex method using a circulator, the disturbance of the carrier power generated by the base station, which was a drawback of the prior art, to the electromagnetic waves re-arriving at the base station is prevented. Since it can be suppressed, the distance between the base station and the target object or the terminal station can be increased.

  According to the present invention, since the disturbance due to the transmission wave itself of the base station can be greatly suppressed with respect to the reception wave received by the base station antenna, the signal-to-noise ratio of the information contained in the reception wave can be improved. . As a result, it is possible to increase the distance between the base station and the target object or the terminal station, and the excellent effect of expanding the application range (region) of the communication system having the communication base station is exhibited.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a circuit diagram showing a configuration of a communication base station according to the first embodiment of the present invention.

  As shown in FIG. 1, a communication base station (hereinafter referred to as a base station) includes a transmission circuit 1, a reception circuit 2, a first coupler 3, a first circulator 4, a second circulator 5, a second coupler 6, A third coupler 7, an antenna 8, and a termination resistor 10 are provided. Conventional transmission and reception circuits are used. In the present embodiment, 90 ° hybrid couplers are used as the first, second and third couplers.

  The 90 ° hybrid coupler has four input / output ports (port 1 to port 4). For example, an electromagnetic wave input from port 1 is output from ports 2 and 3 at an equal distribution ratio. The electromagnetic waves input from the port 4 are synthesized depending on the phase of the electromagnetic waves and output from the port 2 or port 3.

  In the base station of this embodiment, the output of the transmission circuit 1 is coupled to the port 1 of the first 90 ° hybrid coupler 3, and the first circulator is connected to the port 2 of the first 90 ° hybrid coupler 3 (clockwise). Port 1 of the second 90 ° hybrid coupler 3 is coupled to port 3 of the first 90 ° hybrid coupler 3 (clockwise) and port 1 of the second circulator 5 is coupled to port 4 of the first 90 ° hybrid coupler 3. Terminal resistor 10 is coupled, port 2 of the first circulator 4 (forward) is coupled to port 1 of the second 90 ° hybrid coupler 6, and the second 90 ° hybrid coupler 6 (clockwise) A termination resistor 10 is coupled to port 2, an antenna 8 is coupled to port 3 of the second 90 ° hybrid coupler 6, and the second circular resistor is coupled to port 4 of the second 90 ° hybrid coupler 6. Port 2 of the second circulator 5 is coupled to the port 4 of the third 90 ° hybrid coupler 7 and the port 2 of the third 90 ° hybrid coupler 7 is coupled to the port 2 of the third 90 ° hybrid coupler 7. The receiving circuit 2 is coupled to the port 90 of the third 90 ° hybrid coupler 7 and the terminating resistor 10 is coupled to the port 3 of the third 90 ° hybrid coupler 7.

  Here, about the 1st and 2nd circulators 4 and 5, what was inputted from port 1 is outputted from port 2, and what was outputted from port 2 has nonreciprocity outputted from port 3. , Each 90 ° hybrid coupler is connected.

  The operation of the base station of this embodiment will be described.

  The transmission wave generated from the transmission circuit 1 is equally divided by the first 90 ° hybrid coupler 3, and the distributed transmission waves are supplied to the second 90 ° via the first and second circulators 4 and 5, respectively. In-phase synthesis is performed by the hybrid coupler 6, and the radiation is radiated from the antenna 8 to the external space almost losslessly.

  Here, the transmission wave propagating through the first 90 ° hybrid coupler 3, the two circulators 4 and 5, and the second 90 ° hybrid coupler 6 will be described in detail.

  In the first 90 ° hybrid coupler 3, when a transmission wave is input from port 1, the phase of the transmission wave output from port 3 is delayed by π / 4 with respect to the transmission wave output from port 2. Respectively. In the second 90 ° hybrid coupler 6, the transmission wave input from port 1 is output from port 3 with a phase delayed by π / 4 with respect to the transmission wave input from port 4.

  Therefore, the transmission wave output from the port 2 of the first 90 ° hybrid coupler 3, passed through the first circulator 4 and input to the port 1 of the second 90 ° hybrid coupler 6, and the first 90 ° hybrid The transmitted wave that is output from the port 3 of the coupler 3, passes through the second circulator 6, and is input to the port 4 of the second 90 ° hybrid coupler 6 is positioned at the port 3 of the second 90 ° hybrid coupler 6. In-phase synthesis without phase difference.

  The received wave coming from the outside is input from the antenna 8 and is equally divided by the second 90 ° hybrid coupler 6, and by the third 90 ° hybrid coupler 7 via the first and second circulators 4 and 5, respectively. The signals are combined in phase and transmitted to the receiving circuit 2 with almost no loss.

  The received wave propagating through the second 90 ° hybrid coupler 6, the two circulators 4, 5 and the third 90 ° hybrid coupler 7 is the same as in the case of the transmission wave described above. Of the first 90 ° hybrid coupler 3 and the received wave that is input to the port 1 of the third 90 ° hybrid coupler 7 and the first 90 ° hybrid coupler 3. The transmitted wave that passes through the second circulator 5 and is input to the port 4 of the third 90 ° hybrid coupler 7 is synthesized in phase with no phase difference at the port 2 of the third 90 ° hybrid coupler 7.

  On the other hand, a part of the transmission wave equally divided by the first 90 ° hybrid coupler 3 leaks (wraps around) in the first and second circulators 4 and 5 and propagates to the third 90 ° hybrid coupler 7. Resulting in. However, since these sneak waves are subjected to reverse phase synthesis by the third 90 ° hybrid coupler 7, transmission to the receiving circuit 2 is substantially blocked.

  Next, transmission waves propagating through the first 90 ° hybrid coupler 3, the two circulators 4 and 5, and the third 90 ° hybrid coupler 7 will be described in detail.

  In the first 90 ° hybrid coupler 3, when a transmission wave is input from port 1, the phase of the transmission wave output from port 3 is delayed by π / 4 with respect to the transmission wave output from port 2. Respectively. In the third 90 ° hybrid coupler 7, the transmission wave input from the port 4 is output from the port 2 with a phase delayed by π / 4 with respect to the transmission wave input from the port 1.

  Therefore, the transmission wave output from the port 2 of the first 90 ° hybrid coupler 3, passed through the first circulator 4 and input to the port 1 of the second 90 ° hybrid coupler 6, and the first 90 ° hybrid The transmission wave that is output from the port 3 of the coupler 3, passes through the second circulator 5, and is input to the port 4 of the second 90 ° hybrid coupler 6 is the port 3 of the second 90 ° hybrid coupler 6. The phase difference becomes λ / 2, and reverse phase synthesis is performed.

  According to the communication base station of the present embodiment, the transmission circuit 2 generates the direction division duplex system (DDD system) using the three couplers 3, 6, 7 and the two circulators 4, 5. The power of the transmission wave (carrier wave) itself suppresses disturbance to the reception wave that arrives again at the base station. As a result, the information contained in the received wave can be received by the receiving circuit 2 with a good signal-to-noise ratio, the distance between the base station and the target object or the terminal station can be increased, and the application area of the communication system is expanded. can do.

  Next, an example of a communication base station according to this embodiment will be described. FIG. 2 is a diagram showing a structure of a slave station of the base station of FIG.

  The base station includes a multilayer substrate having a three-layer structure of a surface layer 101, an intermediate ground layer 105, and a back layer 102. A first dielectric layer 103 is formed between the surface layer 101 and the intermediate ground layer 105, and a second dielectric layer 104 is formed between the back layer 102 and the intermediate ground layer 105. The back layer 102 is formed with a third 90 ° hybrid coupler 57 and a receiving circuit 52, and the front layer 101 is formed with a transmission circuit 51, a first 90 ° hybrid coupler 53, a first circulator 54, a second circulator 55, A second 90 ° hybrid coupler 56, a feed line 59, and a termination resistor 50 are formed. The electrical connection relationship of the transmission circuit 51, the reception circuit 52, the first and second circulators 54 and 55, the first to third 90 ° hybrid couplers 53, 56 and 57, and the termination resistor 50 is the same as that of the circuit of FIG. The same.

  The second 90 ° hybrid coupler 56 and the antenna 8 are connected via a feed line 59. One end of the terminating resistor 50 is electrically coupled to the intermediate ground layer 105 through the through hole 114, and the electrical coupling between the first and second circulators and the third 90 ° hybrid coupler 57 is performed through the provided through hole 115. A non-contact penetration is made by the second through hole 116.

  According to this configuration, the communication base station of FIG. 1 can be formed with an integral thin plate structure using a general-purpose printed multilayer board process, and can be realized in a small size and at a low cost.

  Next, a second embodiment will be described with reference to FIG.

  As shown in FIG. 3, the base station of the present embodiment is the same as FIG. 1 except that the base station of FIG. In this embodiment, the base station can be downsized because the carrier wave generator that can realize the transmission circuit with a simple circuit configuration is provided.

  In general, it is difficult for a circulator and a 90 ° hybrid coupler to maintain the same performance in a wide frequency range in practice. In the present embodiment, by using the carrier wave generator 11 that generates a transmission wave having an extremely narrow frequency band, only a single frequency that has a minimum occupied frequency band (there is almost no phase shift) is transmitted through the circulator. Since it leaks into the three 90 ° hybrid couplers 7, it is possible to increase the canceling effect by the reverse phase synthesis of the leaking wave.

  Next, a third embodiment will be described with reference to FIG.

  As shown in FIG. 4, in this embodiment, a signal whose amplitude is modulated from the outside arrives at the base station of the first embodiment. The incoming signal is transmitted to the receiving circuit 2 almost losslessly, as in the first embodiment.

  On the other hand, the output of the transmission circuit 1 that leaks from the transmission circuit 1 to the reception circuit 2 via the circulators 4 and 5 and the 90 ° hybrid couplers 6 and 7 is suppressed, and the sideband component of the amplitude-modulated wave coming from the outside is suppressed. Interference can also be greatly reduced.

  A fourth embodiment will be described with reference to FIG.

  As shown in FIG. 5, the base station of this embodiment is such that a signal whose amplitude is modulated from the outside arrives at the base station of the second embodiment.

  The incoming signal is transmitted to the receiving circuit 2 with almost no loss. The output of the transmission circuit leaking from the transmission circuit 1 to the reception circuit 2 via the circulators 4 and 5 and the 90 ° hybrid coupler 7 can be suppressed. In this embodiment, since the output from the carrier wave generation circuit 11 leaking into the receiving circuit 2 is free of sideband components of the amplitude-modulated wave coming from the outside, interference with the same-band component is further greatly reduced. Can do.

  A fifth embodiment will be described with reference to FIG.

  As shown in FIG. 6, the base station of this embodiment uses a linearly polarized antenna 22 as the antenna 8 in the base station of the first embodiment.

  In general, the linearly polarized antenna 22 has a simple configuration, and in particular, a small and high gain antenna represented by a dipole antenna and a monopole antenna can be realized relatively easily.

  According to this embodiment, there is an effect that the communication base station can be realized with a simple structure at low cost.

  A preferred sixth embodiment will be described with reference to FIG.

  As shown in FIG. 7, the base station of this embodiment uses a circularly polarized antenna 23 as the antenna 8 in the base station of the first embodiment.

  Generally, when a circularly polarized electromagnetic wave is reflected, the rotation direction of the polarized wave changes. For this reason, in the present embodiment, among the electromagnetic waves (received waves) that arrive again at the base station, those that have been reflected an odd number of times and arrived at the circularly polarized antenna 23 have the polarization rotation direction of the circularly polarized antenna 23. The circularly polarized antenna 23 does not receive the signal because it does not match the polarization rotation direction. Therefore, when the base station according to the present embodiment is used in an environment where electromagnetic waves are likely to be reflected, fading caused by interaction between reflected waves can be efficiently suppressed.

  When fading occurs, there occurs a moment when the power of the electromagnetic wave received by the antenna suddenly attenuates, and information on the re-arrival wave (received wave) acquired by the receiving circuit 2 is lost. However, according to the present embodiment, since fading can be greatly reduced, the sensitivity of the base station can be improved even when used in an environment where electromagnetic waves are easily reflected on a time average basis.

  A preferred seventh embodiment will be described with reference to FIG.

  FIG. 8 is a configuration diagram illustrating a structure of a terminal station of a communication system using the communication base station of the above-described embodiment and a communication method between the base station and the terminal station.

  The communication system of this embodiment includes a base station 20 and a terminal station 80 that includes an antenna 18. The terminal station 80 includes a changeover switch 12, a matching circuit 13, a rectifier circuit 14, a smoothing circuit 15, a microprocessor 16, and a memory 17. The changeover switch 12 is connected in parallel to the antenna 18, and the input power of the antenna 18 is input to the rectifier circuit 14 via the matching circuit 13, and becomes the power source of the microprocessor 16 via the smoothing circuit 15. The microprocessor 16 refers to the information stored in the memory 17 in advance, and changes the input impedance of the antenna 18 by opening and closing the changeover switch 12 so that the single-frequency electromagnetic wave 81 radiated from the base station antenna 8 is obtained. Is subjected to amplitude modulation.

  According to the present embodiment, since the electromagnetic wave received by the antenna 18 is used as the power of the terminal station 80, remote communication can be realized without using an internal power source such as a battery. As a result, it is possible to realize wireless information transmission in an environment where it is difficult to use a battery in a terminal station due to environment, maintenance, life, and the like.

  A preferred eighth embodiment will be described with reference to FIG.

  As shown in FIG. 9, the communication system of the present embodiment includes a plurality of terminal stations in the non-power supply wireless monitoring system (the communication system of the previous embodiment), and the configuration of the terminal stations is the same.

  In the present embodiment, there are three terminal stations 91, 92, and 93, and the base station 20 needs to identify and recognize these terminal stations 91, 92, and 93. The terminal stations 91, 92, 93 are provided with antennas 18, 28, 38, respectively, and the ON / OFF pattern of the changeover switch is different in time series according to the contents of the memory provided therein.

  According to this configuration, it is possible to shift the transmission timing of the scattered electromagnetic waves from the antennas 18, 28, and 38 in a certain period, and the base station 20 detects the timing, whereby these three terminal stations 91, 92 are detected. , 93 can be identified.

  According to the communication system of the present embodiment, since the base station can identify a plurality of terminal stations, there is an effect of increasing the communication capacity of the entire communication system.

It is a circuit diagram which shows the structure of the direction division | segmentation duplex base station of suitable 1st embodiment which concerns on this invention. It is a transparent perspective view which shows the detailed structure of the direction division | segmentation duplex base station of FIG. It is a circuit diagram which shows the structure of the communication base station of suitable 2nd embodiment which concerns on this invention. It is a circuit diagram which shows the structure of the communication base station of suitable 3rd embodiment which concerns on this invention. It is a circuit diagram which shows the structure of the communication base station of suitable 4th embodiment which concerns on this invention. It is a circuit diagram which shows the structure of the communication base station of suitable 5th embodiment which concerns on this invention. It is a circuit diagram which shows the structure of the communication base station of suitable 6th Embodiment which concerns on this invention. It is a circuit diagram which shows the structure of the communication base station of suitable 7th embodiment which concerns on this invention. It is a circuit diagram which shows the structure of the communication base station of suitable 8th embodiment which concerns on this invention. It is a block diagram which shows the conventional direction division | segmentation duplex base station.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission circuit 2 Reception circuit 3 1st 90 degree hybrid coupler 4 1st circulator 5 2nd circulator 6 2nd 90 degree hybrid coupler 7 3rd 90 degree hybrid coupler 8 Antenna 10 Termination resistance

Claims (12)

A transmission circuit for generating a transmission wave, an antenna for radiating the transmission wave to the outside and receiving a reception wave from the outside, a reception circuit for receiving the reception wave received by the antenna, and the transmission wave for the antenna In a direction-division duplex base station comprising a circulator for transmitting the received wave to the receiving circuit and transmitting the received wave to the receiving circuit,
The transmission circuit is connected to two circulators via a first coupler that distributes the transmission wave in two, and the antenna combines the transmission wave distributed in two and the reception wave into two. The receiver circuit is connected to the other port of the two circulators via a second coupler that splits the signal into two, and the receiver circuit passes the third coupler that combines the received waves distributed in two. A communication base station connected to another port of two circulators.   The transmission circuit is coupled to port 1 of the first 90 ° hybrid coupler 3, port 2 of the first 90 ° hybrid coupler 3 is terminated with a resistor, and port 3 and port 4 of the first 90 ° hybrid coupler 3 are connected. Are connected to port 1 of the first and second circulators, respectively, and to port 2 of the first and second circulators are connected to ports 1 and 2 of the second 90 ° hybrid coupler 6 respectively. An antenna is coupled to the port 3 of the second 90 ° hybrid coupler 6, the port 4 of the second 90 ° hybrid coupler 6 is terminated with a resistor, and the port 3 of the first and second circulators is connected to the second port. Ports 1 and 2 of the three 90 ° hybrid couplers 7 are coupled, and port 3 of the third 90 ° hybrid coupler 7 is terminated with a resistor. The communication base station according to claim 1, wherein the receiving circuit is coupled to the port 4 of the third 90 ° hybrid coupler 7.   The communication base station according to claim 1, wherein the transmission circuit is a carrier wave generation circuit.   The communication base station according to claim 1, wherein the received wave is amplitude-modulated.   The communication base station according to any one of claims 1 to 4, wherein the transmission wave and the reception wave have the same carrier frequency.   The communication base station according to claim 1, wherein the antenna is a linearly polarized antenna.   The communication base station according to claim 1, wherein the antenna is a circularly polarized antenna.   The first 90 ° hybrid coupler 3, the second 90 ° hybrid coupler 6, the first circulator and the second circulator are mounted on the surface of the substrate, and the third 90 ° hybrid coupler 7 is The communication base station according to claim 1, which is mounted on the back surface of the substrate.   9. The communication base station according to claim 8, wherein the substrate is a multilayer substrate having an inner layer, and a ground layer on which the first, second and third 90 ° hybrid couplers are grounded is formed on the inner layer of the multilayer substrate. .   A communication system comprising the communication base station according to any one of claims 1 to 9, and a plurality of terminal stations provided with a modulation means for switching an antenna and an input impedance of the antenna.   The terminal station includes a rectifier circuit, a microcontroller, a storage circuit, and a changeover switch, supplies energy of electromagnetic waves input from the antenna of the terminal station to the microcontroller through the rectifier circuit, and stores the memory in the microcontroller. The communication system according to claim 10, wherein the input impedance of the antenna is switched by turning on and off the switch according to a predetermined rule based on information stored in the circuit.   The communication system according to claim 11, wherein the polarization format of the base station antenna and the polarization format of the terminal station antenna are the same.

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