JPS6335132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a variable reflectance reflector device that also serves as an antenna, and a device for performing bidirectional communication between a single transmitting station and one or more receiving stations by using it in a slave station. Regarding communication methods.

In the information transmission method conventionally used for normal wireless communication, unidirectional communication is performed from the transmitting station to the receiving station, and when bidirectional communication is performed, both stations have a transmitter and a receiver, respectively. equipment is installed to exchange information through a combination of sending and receiving. On the other hand, radar devices have a transmitting and receiving function, and a primary radar system is well known in which the position and size of a target object are determined by detecting reflected waves of radio waves transmitted toward the target object. In this case, there is a method in which information is transmitted from the radar to the target, and there is also a secondary radar method in which a receiver and transmitter are installed at the target point to decode the information and send a return wave to the radar station. Since this system uses two pairs of transmitters and receivers, it can be judged that it falls under the category of unidirectional communication systems mentioned above.

An object of the present invention is to enable bidirectional communication using one frequency from the viewpoint of current frequency usage where allocation is limited.

Another object of the present invention is to enable bidirectional communication between a single transmitting station and multiple stations using one frequency, and to collect information from multiple stations.

In order to achieve the above object, the present invention provides a variable reflectance reflector device that also serves as an antenna and a single-transmission bidirectional communication system using the same.

In other words, the antenna-cum-variable-reflectance reflector device of the first invention of the present application includes an antenna radiating element, a reflector arranged behind the antenna at a distance, and a switching device connected between the antenna radiating element and the reflector. and means for turning the switching means on and off in order to short-circuit the feeding point of the antenna radiating element to a reflector or match it to a load, and when functioning as a receiving antenna, the switching means is turned on and off. The switching means is turned off to match the feeding point of the antenna radiating element with the receiving circuit of the load, and the switching means is turned on and turned off when functioning as a variable reflectance reflector.
The reflected wave is modulated according to the way it is turned off and repeated.

Further, the single-transmission bidirectional communication system of the second invention of the present application uses the antenna-cum-variable-reflectance-variable reflector device of the first invention on the slave station side. A slave station equipped with a variable reflector that also serves as an antenna receives the transmitted radio waves emitted from a master station, which transmits information from the master station to the slave stations, and responds to the received information from the master station. By starting the on/off operation of the switching means on the slave station side, the transmitted radio wave is reflected toward the master station by the variable reflectance reflector that also serves as an antenna of the slave station, and the reflectance at this time is changed to the ON/OFF operation of the switching means.・By changing it according to the off operation, the reflected wave is modulated and information is transmitted from the slave station to the master station.

As mentioned above, in the normal system, communication is performed in one direction from the transmitting station to the receiving station, but in the communication system of the present invention, incoming transmissions from the master station as the transmitting station are sent to the slave station as the receiving station. In addition to having an antenna function to receive radio waves, it also has a reflector function to efficiently reflect incoming radio waves from the master station based on operations in response to received information. It is provided with the ability to receive radio waves, and furthermore, at this time, the reflectance of the radio waves in the slave station can be made variable. In other words, the reflected wave is amplitude-modulated or phase-modulated at the slave station, and by adding information from the slave station to this modulated wave, the transmission point (master station) demodulates the received reflected wave and modulates the amplitude or phase of the reflected wave. This means that information can be obtained from.

As mentioned above, the communication system of the present invention has the feature that a single transmitting station can perform two-way communication with the other station, and has the advantage of being able to overcome the current difficulties in frequency utilization.
Not only is it possible to perform frequency bidirectional communication, but it also has the advantage of being able to collect information from multiple stations using a single transmitting station.

The present invention will be described based on embodiments with reference to the drawings. FIG. 1a is a perspective view showing a conceptual configuration of a variable reflectance element 1 that serves as a slave station antenna, which is the basis of the invention, and FIG. 1 is a circuit diagram showing the configuration principle of 1, in which 2 is an antenna radiation element, 3 is a reflector, 4 is a switching diode for making the reflectance variable, 5 is a DC blocking circuit, 6 is a high frequency blocking circuit, and 7 is a high frequency blocking circuit. Bias power supply for driving the diode, 8 indicates a switch.

FIGS. 2a and 2b are conceptual diagrams of a variable reflector serving as an antenna and constructed using the element 1.
It is placed at the zero focus position. This element 1 does not necessarily have to be flat like the illustrated example,
For example, it is preferable to curve it in accordance with the curvature of the surface of a radio wave lens or the focal plane of a radio wave reflecting mirror. According to such a variable reflector that also serves as an antenna, by turning off the switch 8, the antenna radiation element 2 matches the load on the terminal 11 side and functions as a receiving antenna, and the high frequency output of the received radio wave is It is obtained at the terminal 11 via the DC blocking circuit 5. Furthermore, when the switch 8 is turned on, the antenna radiation element 2 is equivalently short-circuited by the switching diode 4, and therefore, all incident radio waves are reflected here and efficiently transmitted as reflected waves through the radio wave lens 9 or the radio wave reflector 10. Good to be returned to space. By repeating ON/OFF of the switch 8, the reflected wave undergoes amplitude modulation. Depending on how this ON/OFF is repeated, pulse modulation, frequency modulation, etc. are possible.

FIG. 3 is a block diagram showing an example of the basic system configuration of the single-transmission bidirectional communication system according to the present invention. In FIG. 3, 12 is a master station, 13 is a slave station, and 14 is a variable reflector serving as an antenna and configured as described above, provided in the slave station 13.
The master station 12 transmits the information content to be transmitted to a transmitter 16 provided by a modulator 15, a transmitting/receiving antenna 17 and a duplexer 18, a receiver 19 for receiving reflected waves, and decoding the information in the reflected waves. It includes a demodulator 20 and a recorder 21.
In addition to the variable reflectance reflector 14 which also serves as an antenna, the slave station 13 includes a receiver 22 for receiving the received high frequency output from the reflector 14, a demodulator 23 thereof, and a sensor for measuring environmental conditions in the slave station. Reply signal generator 24, demodulator 23
reply signal generator 2 according to the information content of the output.
The encoder 25 includes an encoding circuit 25 for encoding the output signal of No. 4, a modulator 26 for controlling the switch 8 on and off based on the code signal from the encoding circuit 25, and the like.

Incidentally, when the modulator 26 is not producing an output, the antenna-cum-variable reflectance reflector 14 is in a state of functioning as a receiving antenna.

In FIG. 3, modulated radio waves transmitted from the master station 12 are received by the antenna-cum-variable reflector 14 at the slave station 13, detected and demodulated by the receiver 22 and demodulator 23, and then transmitted from the master station 12. Information or command content is decoded. When attempting to transmit reply information or measurement data etc. from the slave station 13 to the master station according to this information or command content,
The output of the demodulator 23 commands the encoding circuit 25, and the signals such as these data from the signal generator 24 are converted into codes of reflectance changes due to ON/OFF of the switch 8 of the reflector 14 by the encoding circuit 25 and the modulator 26. Used as a signal to modulate reflected waves. Therefore, the reflected wave from the reflector 14 at this time is modulated with a code signal according to the output content of the signal generation circuit 24, and in the master station 12, this modulated reflected wave is received by the receiver 19 and sent to the demodulator 20. The information from the slave station 13 is thus demodulated by the recorder 21.
This is what is acquired. In such a system configuration, the synchronization pulse can be detected by the receiver 19 with respect to the transmitted wave from the master station 12, so it is easy to synchronize the modulated wave of the reflected wave, and therefore the reliability of transmission is improved. It is something that can be improved.

4a to 4e show examples of operating waveforms of transmitted waves, reflected waves, etc. in the communication system according to the present invention shown in FIG. 3. FIG. 4a shows an enlarged view of the transmitted wave pulses from the master station 12, and shows an example in which a pulse code of 3 out of 6 pulses selection type is used for information transmission. The transmission wave pulse consists of a pair of start pulses with a narrow pulse interval to indicate the start time, and three pulses arbitrarily selected from six pulse positions (times). The signal is transmitted at a predetermined repetition period T as shown in FIG. 4b. The information in the transmitted wave pulse is contained in the positions (times) of the three arbitrarily selected pulses mentioned above. Child station 13
The transmitter receives and demodulates the transmitted wave pulses, and deciphers the transmitted information or command content from the combination of the three pulse positions. According to this information or command content, the slave station 13 encodes the information or measurement data to be responded to (for example, temperature, wind direction, wind speed, etc. at the slave station) and sends it to the reflector 14.
changes the reflectance of In this case, the wave reflected by the reflector 14 is modulated by a change in reflectance, but the period T' of this modulation is set to be longer than the repetition period T of the transmitted wave pulse, as shown in FIG. 4C. .

In this way, the transmitted wave is modulated by the reflector 14 and has a period longer than the transmission repetition period T, as shown in FIG. 4C.
The reflected wave modulated by T' is returned toward the master station 12. In the master station 12, this modulated reflected wave is received by a receiver 19, and after peak-hold detection is performed by a demodulator 20, the code is decoded as shown in FIG. 4e by shaping the waveform as shown in FIG. Information or measurement data sent from the slave station 13 is recorded on the recorder 21.

In addition to the above-mentioned pulse code modulation, amplitude modulation, phase modulation, and other modulation methods can be used as the modulation method for the transmitted wave at the master station 12 and the modulation method for the reflected wave at the slave station 13. is applicable.

Furthermore, in the single transmission bidirectional communication system of this invention,
It is possible to arrange a plurality of slave stations 13 as shown in FIG. Convenient for collecting. in this case,
The master station sends a command to a specific slave station, and the slave station identifies its own call, responds to it, and sends back data. By sequentially performing this for a plurality of slave stations, the central master station can collect data from slave stations distributed at a plurality of locations. In addition, the transmitting and receiving antenna of the master station is always rotated in a horizontal plane, and the master station receiving system is equipped with an azimuth gate and a distance gate that extract reflected waves for the pre-known azimuth and distance of each slave station. It also becomes possible to collect information from each slave station almost in parallel.

As described above, in the communication system of the present invention, only one master station has a transmission function, and bidirectional communication is possible between this master station and other slave stations that do not have a transmission function. Not only is communication possible, but even if a large number of slave stations are installed to collect information, these slave stations do not require transmitters, so data can be transmitted from multiple points using a single frequency, reducing frequency usage. It is clear that this method has many advantages from the viewpoint of surface and radio wave pollution.

[Brief explanation of the drawing]

FIG. 1a is a perspective view showing the conceptual configuration of a variable reflectance element that also serves as a station antenna, which is the basis of this invention;
Figure b is a circuit diagram showing the principle of construction of this element, Figures 2a and b are conceptual diagrams of a variable reflector that also functions as an antenna, and Figure 3
The figure is a block diagram showing an example of the basic system configuration of the single-transmission bidirectional communication system of the present invention.
e is a diagram showing waveforms for explaining the operation of the communication system of the present invention. 1: Variable reflectance element that also serves as an antenna, 2: Antenna radiation element, 3: Reflector, 4: Switching diode, 5: DC blocking circuit, 6: High frequency blocking circuit, 7: Bias power supply for driving the diode, 8: Switch, 9: Radio wave lens, 10: Radio wave reflector, 1
1: Output terminal, 13: Slave station, 14: Variable reflectance that also serves as an antenna, 15: Modulator, 16: Transmitter, 17: Transmitting/receiving antenna, 18: Duplexer, 19: Receiver, 20: Demodulator, 21: Recorder, 22: Receiver, 23: Demodulator, 24: Signal generator, 25: Encoding circuit, 26: Modulator.

Claims (1)

[Scope of Claims] 1. An antenna radiating element, a reflector arranged at a distance behind the antenna radiating element, a switching means connected between the antenna radiating element and the reflector, and a power supply for the antenna radiating element. 1. A variable reflectance reflector device serving as an antenna, comprising means for turning on and off the switching means in order to short-circuit a point to a reflector or to match a load. 2. An antenna radiating element, a reflector arranged at a distance behind the antenna radiating element, switching means connected between the antenna radiating element and the reflector, and short-circuiting the feeding point of the antenna radiating element to the reflector. Alternatively, a variable reflector device that also serves as an antenna and is equipped with means for turning the switching means on and off in order to match the load is used on the slave station side, and the transmitted radio waves emitted from the master station having a transmission function are used also as the antenna. The slave station receives the information using the variable reflectance reflector device and transmits the information from the master station to the slave station, and in response to the received information from the master station, the slave station uses the variable reflectance reflector device that also serves as an antenna. The transmitted radio waves from the master station are reflected toward the master station, and the reflectance of the reflector device at this time is changed in accordance with the on/off operation of the switching means, thereby modulating the reflected waves and transmitting them from the slave station. A single-transmission bidirectional communication method characterized by transmitting information to a master station.