RU2454758C1 - Microwave switch - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: in microwave switch containing a tee-piece the first leg of which is the input, the second and third legs are the first and second outputs correspondingly, in the second leg at a distance equal to λ/4 from tee-piece branch point there installed is a first group of microwave diodes switched in parallel that consists of one or several microwave diodes, in the third leg at a distance equal to λ/4 from tee-piece branch point there included is a quarter-wave stub at the end of which there installed is the second group of microwave diodes in parallel that consists of one or several microwave diodes, the third leg represents a quarter-wave section of coupled line to the secondary line of which there connected in parallel is at least one additional diode.

EFFECT: increase of operating frequencies band with maintaining the level of operating power without control scheme complication.

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Description

The invention relates to techniques for ultra-high frequencies (microwave) and can be used to switch microwave signals in feeder paths for various purposes, in particular when creating a microwave receive-transmit switch.

Semiconductor microwave switches have the following characteristics: high speed, low weight, long service life.

When developing microwave devices, the problem arises of creating a microwave switch to a large power level having a wide operating frequency band and a simple control circuit.

So, in a remote analogue of the claimed invention - a microwave switch containing the first and second pin diodes connected in series, the connection point of which is the input of the microwave switch, and the first and second output channels are connected to their external terminals, parallel to which the third and fourth are connected pin diodes and a low-pass filter, the first and second pin diodes are turned on according to, a low-pass filter is connected to their external terminals, the cutoff frequency of which is lower than the frequency of the operating range, while the first and second pin diodes are connected respectively to the third and fourth p-i-n diodes with the same electrodes (ed. St. USSR No. 1201925, Н01Р 1/15, 1985), a wide operating frequency band is provided.

However, this device cannot be used to switch high-level power. Firstly, this is due to the fact that in this device microwave diodes are connected in series. The difficulties associated with the removal of heat from the diodes do not allow using this option to turn on the diodes when switching high levels of average power. The switched peak power is limited by the fact that the sum of the amplitude of the alternating voltage acting on the diode and the reverse bias voltage should not exceed the breakdown voltage (more precisely, the maximum allowable instantaneous voltage). (Reference book. Semiconductor devices. Microwave diodes. Tomsk MGP "RASKO", 1992, p. 92). The permissible instantaneous voltage for microwave diodes usually does not exceed 1000 V. An increase in breakdown voltage, in addition, also leads to a decrease in the speed of microwave diodes, and as a result, to a decrease in the speed of microwave switches (Lebedev I.V., Shnitnikov A.S., Kuptsov EI Solid-state microwave limiters of a problem and solution (review), Izv.Vysshikh MB and SSS of the USSR. Radioelectronics, 1985, v. 28, No. 10 p. 37). The disadvantage of this and similar devices is that it is necessary to simultaneously apply a control bias to different groups of diodes of different polarity, while the power of the control source is consumed continuously, which greatly complicates the device of the control source.

When creating microwave switches for a high power level, circuits with parallel connection of diodes to the main line are used.

A closer analogue, chosen as a prototype due to the similarity of the technical task being performed, is a microwave switch (Ilchenko M.E., Osipov V.G. Electrically controlled microwave switches on semiconductor diodes (review), Izv. Universities of the USSR. Radio engineering, 1977, v.20, No. 2 p.10), containing a tee, the first shoulder of which is the input, the second and third - the first and second outputs, respectively, in the second shoulder at a distance equal to λ / 4 from the tee branch assembly, parallel connected first group of microwave diodes, consisting one of several microwave diodes, in the third arm at a distance equal to λ / 4 from the branching unit of the tee, a quarter-wave loop is included, at the end of which a second group of microwave diodes consisting of one or several microwave diodes is installed in parallel.

To control this device, a control bias of the same polarity is supplied to all groups of microwave diodes, and when a negative bias is applied, the power of the control source is practically not consumed. All this greatly simplifies the control circuit, reduces the level of power consumption. Using this switch as a “transmit-receive” switch can significantly increase the switching power due to the fact that the diodes at high power work only in forward bias mode, and, moreover, what is important, when creating a “transmit-receive” switch, you can use restrictive microwave diodes.

However, this device, as a device with parallel connection of diodes to the main line, is characterized by a narrow operating frequency band (microwave phase shifters and switches. Features of the creation of pin diodes in integral design. G. Khizh, I. Vendik, E. Serebryakova . - M .: "Radio and Communications", 1984, p.22-23).

To increase the working frequency band, the wave impedance of the quarter-wave loop is reduced, at the end of which a second group of microwave diodes is connected in parallel. However, since the operating power of the device is inversely proportional to the wave impedance of the line into which the diode is connected, this leads to a decrease in the operating power (Reference. Semiconductor devices. Microwave diodes. Tomsk MGP "RASKO", 1992, p. 92).

The technical result of the invention is an increase in the band of operating frequencies, while maintaining the level of operating power, without complicating the control circuit.

The specified technical result is achieved by the fact that in the microwave switch containing a tee, the first arm of which is the input, the second and third are the first and second outputs, respectively, in the input, the second and third are the first and second outputs, respectively, in the second arm at a distance equal to λ / 4 from the tee branch node, a first group of microwave diodes is installed in parallel, consisting of one or more microwave diodes, in the third arm at a distance equal to λ / 4 from the tee branch node, a quarter-wave loop is included, at the end of which a second group of microwave diodes is installed, connected in parallel, consisting of one or more microwave diodes, the third arm is made in the form of a quarter-wave segment of a connected line, at least one additional diode is connected in parallel to its secondary line.

Figure 1 shows a diagram of the proposed microwave switch.

The microwave switch contains a tee, the first shoulder 1 of which is the input, the second 2 and third 3 are the first and second outputs, respectively, in the second arm 2 at a distance equal to λ / 4 from the branch node of the tee 4, the first group of microwave diodes 5 is installed in parallel consisting of one or more microwave diodes, in the third arm 3 at a distance equal to λ / 4 from the branch node of the tee 4, a quarter-wave cable 6 is included, at the end of which a second group of microwave diodes 7, consisting of one or more microwave diodes, is installed in parallel,moreover, the third arm 3 is made in the form of a quarter-wave segment of a connected line, to the secondary line 8 of which at least one additional diode 9 is connected in parallel. Separating capacitors 10 are used to decouple microwave signals and bias voltages. There are no capacitors in the receive-transmit microwave switch using limiting microwave diodes, the diodes are connected directly to the line.

The microwave switch operates as follows.

When a positive bias microwave switch is applied to all diodes 5, 7, 9 (for a receive-transmit microwave switch using limiting microwave diodes, the diodes open with a high power level signal), the diodes 5, 7, 9 open. Open diodes 5, 7 form two short-circuited quarter-wave loops spaced a distance equal to a quarter of the wavelength, one of them is formed by a quarter-wave segment of the second arm 2 with open diodes 5 installed at the end of the segment, the other by a quarter-wave cable 6, at the end of which is installed parallel-connected second group of open microwave diodes 7. As a result, the RF signal from the input (arm 1) goes to the output (arm 3) (for the receive-transmit microwave switch using limit microwave H diodes The RF signal from the transmitter connected to arm 3 is fed to arm 1, which is the antenna input). A segment of the connected line (arm 3) is designed so that when the diode 9 is open, the impedance of arm 3 is equal to the impedance of arm 1. This achieves good matching and low losses when the microwave signal passes from the input (arm 1) to the output (arm 3).

When applying to all diodes 5, 7, 9, the microwave switch is a negative bias (for the microwave switch "receive-transmit" using limiting microwave diodes when the signal is low power level). Microwave diodes do not open, diodes 5, 7, 9 are closed and are capacitors. The RF signal, since the third output is turned off, comes from the input (shoulder 1) to the output (shoulder 2). For the microwave switch "transmit-receive" using restrictive microwave diodes, the RF signal from the antenna (arm 1) is fed to arm 2, which is the input of the receiving device. A segment of the connected line (arm 3) is designed so that when the diode 9 is closed, the impedance is less than the impedance of arm 3 and the quarter-wave loop 6. A decrease in the impedance of arm 3 relative to the wave impedance of the quarter-wave loop 6 leads to an expansion of the operating frequency band of the device (Designing lens, scanning, wide-range antennas and feeder devices. M.S. Zhuk, Y. B. Molochkov. - M .: "Energy", 1973, S. 391-393). Since the ratio of the wave impedance of the arm 3 to the impedance of the loop 6 affects the magnitude of the bandwidth of the working frequencies, by reducing the impedance of the arm 3 and not increasing the impedance of the loop 6, you can expand the band of operating frequencies without reducing the level of operating power, or increase operating power level while maintaining the operating frequency band. Since the control voltage is supplied with the same polarity to all microwave diodes, this does not complicate the control circuit, and, in addition, allows the use of limiting microwave diodes to create a receive-transmit switch.

Claims (1)

A microwave switch containing a tee, the first arm of which is the input, the second and third are the first and second outputs, respectively, in the second arm of which at a distance equal to λ / 4 from the branching unit of the tee, a first group of microwave diodes is installed in parallel, consisting of one or more microwave diodes, in the third arm at a distance equal to λ / 4 from the branching node of the tee, a quarter-wave loop is included, at the end of which a second group of microwave diodes consisting of one or more Microwave diodes, characterized in that the third leg is designed as a quarter-wave length line connected, to the secondary side of which is connected in parallel to at least one additional diode.