A New X-Band All-Solid-State Transmitter

Abstract

The invention discloses a novel X-band all-solid-state transmitter, which relates to the technical field of microwave measurement. The transmitter comprises a feeding network and two-stage GaAs power amplifiers, a first amplifying module, a microstrip isolator, a first microstrip coupler, a first coaxial waveguide converter, a second amplifying module, a waveguide dual-directional probe coupler and a waveguide ring / isolator which are connected in sequence. The input end of the first-stage GaAs power amplifier is used as the input end of the all-solid-state transmitter to access a radio frequency signal, and the output end of the waveguide ring / isolator is used as the output end of the all-solid-state transmitter to connect an antenna port. The feeding network is used to supply power to the two-stage GaAs power amplifiers, the first amplifying module and the second amplifying module. The tiny radio frequency signal input to the all-solid-state transmitter is amplified by four stages of the two-stage GaAs power amplifiers, the first amplifying module and the second amplifying module to output a high-power radio frequency signal. Two groups of power distributors / synthesizers are used to ensure that the high-power device has good power synthesis efficiency.

Description

Technical Field

[0001] The invention relates to the field of microwave measurement technology, in particular to a novel X-band all-solid-state transmitter. Background Art

[0002] Compared with electric vacuum power amplifiers, microwave solid-state amplifiers have significant advantages: high reliability, long life, the life of a single tube of a microwave solid-state amplifier is about one million hours, while that of an electric vacuum amplifier is only several thousand hours; low voltage operation, the power supply voltage used by microwave solid-state amplifiers is generally less than 50V, safe operation, small size, and simple structure. Therefore, they are favored by more radar transmitter developers and users.

[0003] my country began to develop all-solid-state radar transmitters in the early 1970s. After nearly 50 years of efforts, many all-solid-state radar transmitters have been put into use. At present, all-solid-state radar transmitters have gradually occupied a dominant position in the S-band and below, and their design technology has become mature. However, at the high end of the frequency, high-power transmitters are still dominated by vacuum tube transmitters. In the past, the power tubes used in domestic X-band solid-state power amplifiers were mainly GaAs FET power tubes, and the design technology of high-power amplifiers was mainly GaAs FET amplifier design technology and power synthesis design technology. However, due to the limitation of the working voltage of GaAs FET power tubes, the output power level was relatively low. At the same time, due to the influence of process level and cost, the research on high-power solid-state transmitters in China lags far behind that of foreign countries. Solid-state amplifiers are only partially used in active phased array radars and as the driving stage of electric vacuum transmitters. Traditional high-power solid-state transmitters are large in size, low in efficiency, complex in circuit structure, and relatively low in output capacity. Summary of the invention

[0004] In view of the above problems and technical requirements, the inventors proposed a novel X-band all-solid-state transmitter. Based on GaN FET power tubes, amplifiers and power synthesis design technology, a novel X-band 400W microwave all-solid-state transmitter was designed.

[0005] The technical solution of the present invention is as follows:

[0006] A novel X-band all-solid-state transmitter comprises a feeding network and a two-stage GaAs power amplifier, a first amplifying module, a microstrip isolator, a first microstrip coupler, a first coaxial waveguide converter, a second amplifying module, a waveguide dual-directional probe coupler and a waveguide ring / isolator connected in sequence. The input end of the first-stage GaAs power amplifier is used as the input end of the all-solid-state transmitter to access a radio frequency signal, and the output end of the waveguide ring / isolator is used as the output end of the all-solid-state transmitter to connect an antenna port; the feeding network is used to supply power to the two-stage GaAs power amplifier, the first amplifying module and the second amplifying module; the first coaxial waveguide converter is used to convert a microstrip into a waveguide; the tiny radio frequency signal input to the all-solid-state transmitter is amplified in four stages by the two-stage GaAs power amplifier, the first amplifying module and the second amplifying module to output a high-power radio frequency signal.

[0007] Its further technical solution is that the first amplification module includes a 3dB input bridge, a 3dB output bridge and a GaN power amplifier, the input end of the GaN power amplifier I is connected to the first output end of the 3dB input bridge, the input end of the GaN power amplifier II is connected to the second output end of the 3dB input bridge, the input end of the 3dB input bridge is connected to the second-stage GaAs power amplifier, the output end of the GaN power amplifier I is connected to the first input end of the 3dB output bridge, the output end of the GaN power amplifier II is connected to the second input end of the 3dB output bridge, and the output end of the 3dB output bridge is connected to a microstrip isolator;

[0008] The second amplification module includes a waveguide power divider, a waveguide power combiner, and two second coaxial waveguide converters, an input matching circuit, a GaN power tube, an output matching circuit, a second microstrip coupler, and a third coaxial waveguide converter that are sequentially connected. The input end of the waveguide power divider is connected to the first coaxial waveguide converter, and the two output ends of the waveguide power divider are respectively connected to the second coaxial waveguide converter. The second coaxial waveguide converter is used to convert the waveguide into a microstrip. The two input ends of the waveguide power combiner are respectively connected to the third coaxial waveguide converter. The third coaxial waveguide converter is used to convert the microstrip into a waveguide. The output end of the waveguide power combiner is connected to the waveguide dual-directional probe coupler.

[0009] A further technical solution is that the all-solid-state transmitter also includes a pulse modulation circuit, and the voltage output to the two-stage GaAs power amplifier, the first amplification module and the second amplification module through the feed network is firstly passed through the pulse modulation circuit to achieve negative power-off protection, and then the two-stage GaAs power amplifier, the first amplification module and the second amplification module are powered;

[0010] The first pulse modulation circuit includes a diode, a triode, a first AND gate, a first driver and a MOS tube. The first input end of the first AND gate is connected to the pulse modulation signal and is also grounded through the first resistor. The second input end of the first AND gate is connected to the anode of the first diode through the second resistor and the third resistor as the enable end of the negative power-off protection. The common end of the second resistor and the third resistor is connected to the first power supply. The cathode of the first diode is connected to the cathode of the second diode. The anode of the second diode is connected to the first negative power supply of the feeding network. The base of the triode is connected to the common end of the first diode and the second diode and then to the ground through the fourth resistor. The collector of the triode is connected to the second input end of the first AND gate. The emitter of the triode is grounded. The first AND gate The output end of the first driver is respectively connected to the two input ends of the first driver, and is also grounded through a fifth resistor. The first output end of the first driver is connected to the gate of the second MOS tube, the source of the second MOS tube is connected to the leakage voltage power supply of the two-stage GaAs power amplifier of the feeding network, the drain of the second MOS tube is connected to the second-stage GaAs power amplifier, the second output end of the first driver is connected to the gate of the first MOS tube, the source of the first MOS tube is connected to the first power supply, and the drain of the first MOS tube is connected to the first-stage GaAs power amplifier; if the first negative power supply is powered off, the first AND gate outputs a low level, the first driver is not turned on, and the first MOS tube and the second MOS tube are also not turned on, so as to realize the negative power-off protection function.

[0011] Its further technical solution is that the second pulse modulation circuit includes a second driver and a third MOS tube, the input end of the second driver is connected to the pulse modulation signal through the sixth resistor, and is also grounded through the sixth resistor and the seventh resistor, the enable end of the second driver is connected to the first negative power supply through the eighth resistor, and is also grounded through the first capacitor, the power supply end of the second driver and the source of the third MOS tube are respectively connected to the leakage voltage power supply of the GaN power amplifier of the feeding network, the power supply end of the second driver is also grounded through the second capacitor and the third capacitor, the output end of the second driver is connected to the gate of the third MOS tube through the ninth resistor, the tenth resistor is connected between the gate and the source of the third MOS tube, and the drain of the third MOS tube is connected to the GaN power amplifier; if the first negative power supply is powered off, the second driver outputs a high level, then the third MOS tube is not turned on, and the negative power-off protection function is realized; the pull-down port of the second driver is connected to the drain of the third MOS tube, and the drain of the third MOS tube is quickly discharged;

[0012] The third pulse modulation circuit includes a third driver and a fourth MOS tube. The connection circuit structure of the third driver and the second driver is the same as that of the input terminal, the enable terminal, the output terminal and the pull-down port. The power supply terminal of the third driver and the source of the fourth MOS tube are respectively connected to the leakage voltage power supply of the GaN power tube of the feeding network, and the power supply terminal of the third driver is also grounded through the fourth capacitor, the fifth capacitor, the sixth capacitor, the seventh capacitor, the eighth capacitor and the ninth capacitor respectively; if the first negative power supply is powered off, the third driver outputs a high level, and the fourth MOS tube is not turned on, realizing the negative power-off protection function; the pull-down port of the third driver is connected to the drain of the fourth MOS tube, realizing the drain fast discharge function of the fourth MOS tube.

[0013] Its further technical solution is that the all-solid-state transmitter also includes a pulse modulation BIT alarm circuit, including a second AND gate, a third AND gate and a fourth AND gate, the first input end of the second AND gate is connected to the temperature BIT signal, the second input end is connected to the transmitting output port standing wave BIT signal, the output end of the second AND gate is connected to the first input end of the fourth AND gate, the first input end of the third AND gate is connected to the current overcurrent BIT signal, the second input end is connected to the pulse modulation input signal, the output end of the third AND gate is connected to the second input end of the fourth AND gate, and the output end of the fourth AND gate outputs the pulse modulation signal; if any one of the temperature BIT signal, the transmitting output port standing wave BIT signal, the current overcurrent BIT signal and the pulse modulation input signal is at a low level, the pulse modulation signal output by the pulse modulation BIT alarm circuit is also at a low level, each pulse modulation circuit is not turned on, and the two-stage GaAs power amplifier, the first amplification module and the second amplification module do not work.

[0014] Its further technical solution is that the all-solid-state transmitter also includes a power BIT alarm circuit, including an inductor, a third diode and a first comparator. The anode of the third diode is connected to the output ends of the first microstrip coupler and the second microstrip coupler as the input end of the power BIT alarm circuit, and is also grounded through the inductor. The cathode of the third diode is connected to the first end of the tenth capacitor, the first end of the eleventh resistor and the first input end of the first comparator, respectively. The second end of the tenth capacitor and the second end of the eleventh resistor are both grounded. The second input end of the first comparator is connected to the first end of the twelfth resistor and the first end of the thirteenth resistor, respectively. The second end of the twelfth resistor and the power supply end of the first comparator are respectively connected to the first power supply, the second end of the thirteenth resistor and the ground end of the first comparator are both grounded, and the output end of the first comparator outputs a power BIT signal; if the voltage of the first input end of the first comparator is less than the voltage of the second input end, the power BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0015] Its further technical solution is that the all-solid-state transmitter also includes a temperature BIT alarm circuit for monitoring high-power devices in the first amplification module and the second amplification module, including a temperature sensor and a second comparator, and the temperature sensor is placed close to the high-power devices in the first amplification module and the second amplification module; the first input end of the second comparator is connected to the temperature sensor, and the second input end of the second comparator is respectively connected to the first end of the fourteenth resistor and the first end of the fifteenth resistor, the power supply end of the temperature sensor, the second end of the fourteenth resistor and the power supply end of the second comparator are respectively connected to the first power supply, the second end of the fifteenth resistor and the ground end of the second comparator are both grounded, and the output end of the second comparator outputs a temperature BIT signal; if the voltage of the first input end of the second comparator is greater than the voltage of the second input end, the temperature BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0016] Its further technical solution is that the all-solid-state transmitter also includes an antenna port matching BIT alarm circuit, including a fourth diode and a third comparator, the second input end of the third comparator has the same connection circuit structure as the first input end of the first comparator, the anode of the fourth diode is connected to the reverse end of the waveguide dual-directional probe coupler as the input end of the antenna port matching BIT alarm circuit, the first input end of the third comparator is respectively connected to the first end of the sixteenth resistor and the first end of the seventeenth resistor, the second end of the sixteenth resistor is grounded, the second end of the seventeenth resistor is connected to the first power supply, and the output end of the third comparator outputs a transmission output port standing wave BIT signal; if the voltage of the second input end of the third comparator is greater than the voltage of the first input end, the transmission output port standing wave BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0017] Its further technical solution is that the all-solid-state transmitter also includes a current BIT alarm circuit, including a current detector, a fourth comparator and a fifth comparator, the positive input end of the current detector is respectively connected to the first end of the eighteenth resistor, the first end of the nineteenth resistor and the first end of the twentieth resistor, the common end formed by the first ends of the eighteenth resistor, the nineteenth resistor and the twenty-third resistor is connected to the pulse modulation circuit, the negative input end of the current detector is respectively connected to the second end of the eighteenth resistor, the second end of the nineteenth resistor and the second end of the twenty-third resistor, the common end formed by the second ends of the eighteenth resistor, the nineteenth resistor and the twenty-third resistor is connected to the high-power device corresponding to the pulse modulation circuit, the eighteenth resistor, the nineteenth resistor and the twenty-third resistor are power resistors, the output end of the current detector is respectively connected to the second input end of the fourth comparator and the first input end of the fifth comparator, the first input end of the fourth comparator is respectively connected to the first end of the twenty-first resistor and the first end of the twenty-second resistor, the second end of the twenty-first resistor is grounded, the second end of the twenty-second resistor is connected to the first power supply, and the output end of the fourth comparator outputs a current overcurrent BIT signal. If the voltage of the second input end of the fourth comparator is less than the voltage of the first input end, the current overcurrent BIT signal is abnormal and an external alarm device is connected to prompt an alarm;

[0018] The second input terminal of the fifth comparator is respectively connected to the first end of the twenty-third resistor and the first end of the twenty-fourth resistor, the second end of the twenty-third resistor is grounded, the second end of the twenty-fourth resistor is connected to the first power supply, and the output terminal of the fifth comparator outputs a current undercurrent BIT signal. If the voltage of the first input terminal of the fifth comparator is greater than the voltage of the second input terminal, the current undercurrent BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0019] Its further technical solution is that the input matching circuit includes an impedance line, a capacitor, a twenty-fifth resistor and a first fan-out line, the first end of the eleventh capacitor is connected to the second coaxial waveguide converter as the input end of the input matching circuit, the second end of the eleventh capacitor is connected to the gate of the GaN power tube as the output end of the input matching circuit, the first impedance line is connected to the two ends of the eleventh capacitor, the second end of the eleventh capacitor is connected to the first end of the thirteenth capacitor, the first end of the fourteenth capacitor, the first end of the fifteenth capacitor and the gate voltage power supply of the GaN power tube of the feeding network respectively through the second impedance line, the first fan-out line and the twenty-fifth resistor, and the second ends of the thirteenth capacitor, the fourteenth capacitor and the fifteenth capacitor are all grounded;

[0020] The output matching circuit includes an impedance line, a capacitor, a twenty-sixth resistor and a second fan-out line. The first end of the twelfth capacitor is connected to the drain of the GaN power tube as the input end of the output matching circuit. The second end of the twelfth capacitor is connected to the second microstrip coupler as the output end of the output matching circuit. The third impedance line is connected to both ends of the twelfth capacitor. The first end of the twelfth capacitor is connected to the first end of the twenty-sixth resistor, the first end of the seventeenth capacitor, the first end of the eighteenth capacitor and the second pulse modulation circuit / third pulse modulation circuit respectively through the fourth impedance line and the second fan-out line. The second end of the twenty-sixth resistor is connected to the first end of the sixteenth capacitor. The second ends of the sixteenth capacitor, the seventeenth capacitor and the eighteenth capacitor are all grounded. The input matching circuit and the output matching circuit realize impedance matching of the input and output of the GaN power tube.

[0021] The beneficial technical effects of the present invention are:

[0022] In the all-solid-state transmitter of the present application, the tiny radio frequency signal input to the all-solid-state transmitter is sequentially amplified by four stages of two-stage GaAs power amplifier, first amplification module and second amplification module to output a high-power radio frequency signal; in the first amplification module and the second amplification module, power distribution / synthesis is achieved through 3dB input / output bridge and waveguide power divider / combiner respectively, both of which have the characteristics of low loss, narrow frequency band, good input and output matching and simple structure; in the second amplification module, the input matching circuit and the output matching circuit achieve impedance matching of the input and output of the GaN power tube; the present application also provides a pulse modulation circuit at the drain of the two-stage GaAs power amplifier, the first amplification module and the second amplification module, and each pulse modulation circuit has no output after the negative power is off, so as to realize the protection of the drain supply voltage of the high-power device and the power supply modulation function; in order to monitor the various states of the all-solid-state transmitter, the present application also provides multiple BIT alarm circuits, thereby realizing temperature monitoring, transmission power monitoring, current monitoring and antenna port matching detection of the all-solid-state transmitter, and completing the detection and protection of high-power devices at all levels;

[0023] According to the measured results, after the transmission excitation signal (3dBm) is amplified by four stages of power using the all-solid-state transmitter of the present application, under the conditions of a transmission pulse width of 500us and a duty cycle of 20%, within the frequency band of 9.3GHz to 9.5GHz, the final output power of the all-solid-state transmitter is 56.6dBm (i.e., 457W), and its synthesis efficiency is improved by 30% compared with that of traditional transmitters. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the all-solid-state transmitter provided in this application.

[0025] Figure 2 This is a model diagram of the H-plane waveguide power divider / combiner provided in this application.

[0026] Figure 3 It is a voltage distribution diagram of the feeding network provided in this application.

[0027] Figure 4 This is a model diagram of the GaN power tube and input / output matching circuit provided in this application.

[0028] Figure 5 is a circuit diagram of an input matching circuit provided in this application.

[0029] Figure 6 is a circuit diagram of an output matching circuit provided in this application.

[0030] Figure 7 It is a circuit diagram of the first pulse modulation circuit provided in this application.

[0031] Figure 8 It is a circuit diagram of the second pulse modulation circuit provided in this application.

[0032] Fig. 9 It is a circuit diagram of the third pulse modulation circuit provided in this application.

[0033] Fig.10 It is a circuit diagram of the pulse modulation BIT alarm circuit provided by this application.

[0034] Fig.11 It is a circuit diagram of the power BIT alarm circuit provided by this application.

[0035] Fig.12 It is a circuit diagram of the temperature BIT alarm circuit provided by this application.

[0036] Fig.13 This is a circuit diagram of the antenna port matching BIT alarm circuit provided by this application.

[0037] Fig.14 It is a circuit diagram of the current BIT alarm circuit provided by this application. DETAILED DESCRIPTION

[0038] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0039] This application discloses a novel X-band all-solid-state transmitter, the schematic diagram of which is shown in FIG. Figure 1As shown, it includes a feeding network and two-stage GaAs power amplifiers, a first amplification module, a microstrip isolator, a first microstrip coupler, a first coaxial waveguide converter, a second amplification module, a waveguide dual-directional probe coupler and a waveguide ring / isolator connected in sequence. The input end of the first-stage GaAs power amplifier is used as the input end of the all-solid-state transmitter to access the radio frequency signal, and the output end of the waveguide ring / isolator is used as the output end of the all-solid-state transmitter to connect the antenna port. The feeding network is used to power the two-stage GaAs power amplifier, the first amplification module and the second amplification module, and the first coaxial waveguide converter is used to convert the microstrip into a waveguide. The tiny radio frequency signal input to the all-solid-state transmitter is amplified by four stages of the two-stage GaAs power amplifier, the first amplification module and the second amplification module to output a high-power radio frequency signal. Among them, each device in the all-solid-state transmitter adopts an existing commercially available module, and its various circuit structures are not introduced in detail here.

[0040] The first amplification module includes a 3dB input bridge, a 3dB output bridge and a GaN power amplifier, the input end of the GaN power amplifier I is connected to the first output end of the 3dB input bridge, the input end of the GaN power amplifier II is connected to the second output end of the 3dB input bridge, the input end of the 3dB input bridge is connected to the second-stage GaAs power amplifier, the output end of the GaN power amplifier I is connected to the first input end of the 3dB output bridge, the output end of the GaN power amplifier II is connected to the second input end of the 3dB output bridge, and the output end of the 3dB output bridge is connected to a microstrip isolator. The microstrip isolator is used to protect the GaN power amplifier.

[0041] The second amplification module includes a waveguide power divider, a waveguide power combiner, and two sequentially connected second coaxial waveguide converters, an input matching circuit, a GaN power tube, an output matching circuit, a second microstrip coupler, and a third coaxial waveguide converter. The input end of the waveguide power divider is connected to the first coaxial waveguide converter, and the two output ends of the waveguide power divider are respectively connected to the second coaxial waveguide converter, and the second coaxial waveguide converter is used to convert the waveguide into a microstrip. The two input ends of the waveguide power combiner are respectively connected to the third coaxial waveguide converter, and the third coaxial waveguide converter is used to convert the microstrip into a waveguide. The output end of the waveguide power combiner is connected to a waveguide dual-directional probe coupler. The first microstrip coupler and the second microstrip coupler are used to increase power.

[0042] In the first amplification module and the second amplification module, power distribution / synthesis is achieved through a 3dB input / output bridge and a waveguide power divider / combiner, both of which have the characteristics of low loss, narrow frequency band, good input and output matching, and simple structure. The waveguide power divider / combiner of the present application adopts an H-plane waveguide power divider / combiner as a power distributor / combiner of the GaN power tube. Its model is as follows Figure 2 As shown, the use of the waveguide power divider / combiner ensures that the GaN power tube has good power combining efficiency.

[0043] The feeding network of the present application includes a DCDC voltage regulator circuit, an LDO voltage regulator circuit, and a power filter. A DC bias feeding network is built to stabilize the +40V power supply into the power supply voltage required by each level of high-power devices on the transmission link. The distribution voltage diagram is shown in FIG. Figure 3 As shown, the +40V power supply is filtered by the first power filter and then outputted as the leakage voltage power supply of the GaN power tube. The +40V power supply is converted into a +28V power supply by the first DCDC voltage regulator circuit, and then converted into a +8.5V power supply by the second DCDC voltage regulator circuit. At the same time, the +28V power supply is filtered by the second power filter and then outputted as the leakage voltage power supply of the GaN power amplifier. The +8.5V power supply is converted into a +8V power supply by the first LDO voltage regulator circuit as the leakage voltage power supply of the two-stage GaAs power amplifier. , after the +8.5V power supply is converted to -5.5V power supply through the third DCDC voltage regulator circuit, it is converted to -5V power supply through the second LDO voltage regulator circuit. The -5V power supply is used as the first negative power supply of the feeding network and is converted to -0.6V power supply, -1.7V power supply and -2V power supply through three third LDO voltage regulator circuits respectively. The -0.6V power supply is used as the gate voltage power supply of the second-stage GaAs power amplifier, the -1.7V power supply is used as the gate voltage power supply of the GaN power amplifier, and the -2V power supply is used as the gate voltage power supply of the GaN power tube. It should be noted that the DCDC voltage regulator circuit, LDO voltage regulator circuit and power supply filter of this application are all existing circuit structures and will not be introduced in detail here.

[0044] In the second amplifier module, the models of the input matching circuit, GaN power tube and output matching circuit are as follows: Figure 4 The input matching circuit includes an impedance line, a capacitor, a twenty-fifth resistor R25 and a first fan-shaped line, and its circuit diagram is shown in FIG. Figure 5 As shown, the first end of the eleventh capacitor C11 is connected to the second coaxial waveguide converter as the input end RFin of the input matching circuit, the second end of the eleventh capacitor C11 is connected to the gate of the GaN power tube as the output end of the input matching circuit, the first impedance line (resistance is 50Ω) is connected to the two ends of the eleventh capacitor C11, the second end of the eleventh capacitor C11 is connected to the first end of the thirteenth capacitor C13, the first end of the fourteenth capacitor C14, the first end of the fifteenth capacitor C15 and the gate voltage power supply of the GaN power tube of the feeding network through the second impedance line, the first fan-shaped line, and the twenty-fifth resistor R25 in sequence, and the second ends of the thirteenth capacitor C13, the fourteenth capacitor C14 and the fifteenth capacitor C15 are all grounded. Among them, the eleventh capacitor C11 realizes the direct isolation of the power supply of the gate voltage and avoids short circuit, the thirteenth capacitor C13, the fourteenth capacitor C14 and the fifteenth capacitor C15 realize the decoupling filtering of the gate voltage, and the twenty-fifth resistor R25 is used to stabilize the gate voltage.

[0045] The output matching circuit includes an impedance line, a capacitor, a twenty-sixth resistor R26 and a second fan-shaped line. The circuit diagram is shown in FIG. Figure 6 As shown, the first end of the twelfth capacitor C12 is connected to the drain of the GaN power tube as the input end of the output matching circuit, the second end of the twelfth capacitor C12 is connected to the second microstrip coupler as the output end RFout of the output matching circuit, the third impedance line (with a resistance of 50Ω) is connected to the two ends of the twelfth capacitor C12, the first end of the twelfth capacitor C12 is connected to the first end of the twenty-sixth resistor R26, the first end of the seventeenth capacitor C17, the first end of the eighteenth capacitor C18 and the second pulse modulation circuit / third pulse modulation circuit respectively through the fourth impedance line and the second fan-shaped line, the second end of the twenty-sixth resistor R26 is connected to the first end of the sixteenth capacitor C16, and the second ends of the sixteenth capacitor C16, the seventeenth capacitor C17 and the eighteenth capacitor C18 are all grounded. The twelfth capacitor C12 realizes the power supply isolation of the leakage voltage and avoids short circuit, the seventeenth capacitor C17 and the eighteenth capacitor C18 realize the decoupling filtering of the leakage voltage, and the twenty-sixth resistor R26 and the sixteenth capacitor C16 are used to stabilize the leakage voltage. The input matching circuit and the output matching circuit realize the impedance matching of the input and output of the GaN power tube, suppress resonance and other functions. The second impedance line and the fourth impedance line are both 1 / 4λ high impedance lines, where λ is the wavelength of the radio frequency signal.

[0046] The all-solid-state transmitter of the present application also includes a pulse modulation circuit. The voltage output to the two-stage GaAs power amplifier, the first amplification module and the second amplification module via the feed network is firstly passed through the pulse modulation circuit to achieve negative power-off protection, and then the two-stage GaAs power amplifier, the first amplification module and the second amplification module are powered.

[0047] The first pulse modulation circuit includes a diode, a transistor Q1, a first AND gate, a first driver and a MOS tube, and its circuit diagram is shown in FIG. Figure 7As shown, the first input end of the first AND gate is connected to the pulse modulation signal T, and is also grounded through the first resistor R1. The second input end of the first AND gate is connected to the anode of the first diode D1 through the second resistor R2 and the third resistor R3 as the enable end of the negative power-off protection. The common end of the second resistor R2 and the third resistor R3 is connected to the first power supply +5V, the cathode of the first diode D1 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is connected to the first negative power supply -5V of the feeding network. The base of the transistor Q1 is connected to the common end of the first diode D1 and the second diode D2 and then grounded through the fourth resistor λR4. The collector of the transistor Q1 The first AND gate is connected to the second input end of the first AND gate, the emitter of the transistor Q1 is grounded, the output end of the first AND gate is respectively connected to the two input ends of the first driver, and is also grounded through the fifth resistor R5, the first output end of the first driver is connected to the gate of the second MOS tube, the source of the second MOS tube is connected to the drain voltage power supply +8V of the two-stage GaAs power amplifier of the feeding network, the drain of the second MOS tube is connected to the second-stage GaAs power amplifier, the second output end of the first driver is connected to the gate of the first MOS tube, the source of the first MOS tube is connected to the first power supply +5V, and the drain of the first MOS tube is connected to the first-stage GaAs power amplifier. If the first negative power supply -5V is powered off, the first AND gate outputs a low level, then the first driver is not turned on, and the first MOS tube and the second MOS tube are also not turned on, realizing the negative power-off protection function.

[0048] The second pulse modulation circuit includes a second driver and a third MOS tube, and its circuit diagram is as follows: Figure 8 As shown, the input terminal IN of the second driver is connected to the pulse modulation signal T through the sixth resistor R6, and is also grounded through the sixth resistor R6 and the seventh resistor R7. The enable terminal EN of the second driver is connected to the first negative power supply -5V through the eighth resistor R8, and is also grounded through the first capacitor C1. The power supply terminal VDD of the second driver and the source of the third MOS tube are respectively connected to the drain voltage power supply +28V of the GaN power amplifier of the feeding network. The power supply terminal VDD of the second driver is also grounded through the second capacitor C2 and the third capacitor C3 respectively. The output terminal OUT of the second driver is connected to the gate of the third MOS tube through the ninth resistor R9, and the tenth resistor R10 is connected between the gate and the source of the third MOS tube. The drain of the third MOS tube is connected to the GaN power amplifier. If the first negative power supply -5V is powered off, the second driver outputs a high level, and the third MOS tube is not turned on, realizing the negative power-off protection function. The pull-down port PD of the second driver is connected to the drain of the third MOS tube, realizing the drain fast discharge function of the third MOS tube, and reducing the drain level discharge time of the third MOS tube.

[0049] The third pulse modulation circuit includes a third driver and a fourth MOS tube, and its circuit diagram is as follows: Fig. 9As shown, the connection circuit structure of the third driver and the second driver is the same as that of the input terminal IN, the enable terminal EN, the output terminal OUT and the pull-down port PD. The power supply terminal VDD of the third driver and the source of the fourth MOS tube are respectively connected to the drain voltage power supply +40V of the GaN power tube of the feed network, and the power supply terminal VDD of the third driver is also grounded through the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8 and the ninth capacitor C9. If the first negative power supply -5V is powered off, the third driver outputs a high level, then the fourth MOS tube is not turned on, and the negative power-off protection function is realized. The pull-down port PD of the third driver is connected to the drain of the fourth MOS tube, realizing the drain fast discharge function of the fourth MOS tube, and reducing the drain level discharge time of the fourth MOS tube. Optionally, the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are all P-channel MOSFET tubes. The first driver, the second driver and the third driver of this application all adopt existing commercially available modules, which will not be described in detail here.

[0050] Optionally, the present application also utilizes multifunctional logic devices and crystal oscillators to implement excessive pulse width and excessive duty cycle protection for the transmitted modulation signal through a firmware program. That is, when the pulse of the transmitted debugging signal exceeds 500us or the duty cycle exceeds 20%, the power supply to each level of high-power devices cannot be completed, thereby achieving protection for each level of high-power devices.

[0051] The all-solid-state transmitter also includes a pulse modulation BIT alarm circuit, the circuit diagram of which is shown in Fig.10 As shown, it includes a second AND gate, a third AND gate and a fourth AND gate, the first input end of the second AND gate is connected to the temperature BIT signal, the second input end is connected to the transmission output port standing wave BIT signal, the output end of the second AND gate is connected to the first input end of the fourth AND gate, the first input end of the third AND gate is connected to the current overcurrent BIT signal, the second input end is connected to the pulse modulation input signal Tin, the output end of the third AND gate is connected to the second input end of the fourth AND gate, and the output end of the fourth AND gate outputs the pulse modulation signal T. If any one of the temperature BIT signal, the transmission output port standing wave BIT signal, the current overcurrent BIT signal and the pulse modulation input signal Tin is at a low level (that is, abnormal), the pulse modulation signal T output by the pulse modulation BIT alarm circuit is also at a low level, each pulse modulation circuit is not turned on, and the two-stage GaAs power amplifier, the first amplification module and the second amplification module do not work.

[0052] The all-solid-state transmitter also includes a power BIT alarm circuit, the circuit diagram of which is shown in Fig.11As shown, it includes an inductor L, a third diode D3 and a first comparator. The anode of the third diode D3 is connected to the output of the first microstrip coupler and the second microstrip coupler as the input end of the power BIT alarm circuit, and the input power amplifier is coupled to the output power. At the same time, it is also grounded through the inductor L. The cathode of the third diode D3 is connected to the first end of the tenth capacitor C10, the first end of the eleventh resistor R11 and the first input end A1 of the first comparator respectively. The second end of the tenth capacitor C10 and the second end of the eleventh resistor R11 are both grounded. The second input end A2 of the first comparator is connected to the first end of the twelfth resistor R12 and the first end of the thirteenth resistor R13 respectively. The second end of the twelfth resistor R12 and the power supply end of the first comparator are connected to the first power supply +5V respectively. The second end of the thirteenth resistor R13 and the ground end of the first comparator are both grounded. The output end Ao of the first comparator outputs a power BIT signal. If the voltage of the first input end of the first comparator is less than the voltage of the second input end, the power BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0053] The all-solid-state transmitter also includes a temperature BIT alarm circuit for monitoring high-power devices in the first amplification module and the second amplification module. The circuit diagram thereof is shown in FIG. Fig.12 As shown, it includes a temperature sensor and a second comparator, and the temperature sensor is placed close to the high-power devices (i.e., GaN power amplifier and GaN power tube) in the first amplification module and the second amplification module. The first input terminal A1 of the second comparator is connected to the temperature sensor, and the second input terminal A2 of the second comparator is respectively connected to the first end of the fourteenth resistor R14 and the first end of the fifteenth resistor R15. The power supply terminal VCC of the temperature sensor, the second end of the fourteenth resistor R14, and the power supply terminal V+ of the second comparator are respectively connected to the first power supply +5V, the second end of the fifteenth resistor R15 and the ground terminal GND of the second comparator are both grounded, and the output terminal Ao of the second comparator outputs a temperature BIT signal. If the voltage of the first input terminal of the second comparator is greater than the voltage of the second input terminal, the temperature BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0054] The all-solid-state transmitter also includes an antenna port matching BIT alarm circuit, the circuit diagram of which is shown in Fig.13As shown, it includes a fourth diode D4 and a third comparator, the second input terminal A2 of the third comparator has the same connection circuit structure as the first input terminal A1 of the first comparator, the anode of the fourth diode D4 is connected to the reverse end of the waveguide dual-directional probe coupler as the input end of the antenna port matching BIT alarm circuit, and is connected to the reverse coupling output power of the transmission output port, the first input terminal A1 of the third comparator is respectively connected to the first end of the sixteenth resistor R16 and the first end of the seventeenth resistor R17, the second end of the sixteenth resistor R16 is grounded, the second end of the seventeenth resistor R17 is connected to the first power supply +5V, and the output terminal Ao of the third comparator outputs the transmission output port standing wave BIT signal. If the voltage of the second input terminal of the third comparator is greater than the voltage of the first input terminal, the transmission output port standing wave BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0055] The all-solid-state transmitter also includes a current BIT alarm circuit, the circuit diagram of which is shown in Fig.14 As shown, it includes a current detector, a fourth comparator and a fifth comparator, the positive input terminal in+ of the current detector is respectively connected to the first end of the eighteenth resistor R18, the first end of the nineteenth resistor R19 and the first end of the twentieth resistor R20, the common end formed by the first ends of the eighteenth resistor R18, the nineteenth resistor R19 and the twenty-third resistor R20 is connected to the pulse modulation circuit, the negative input terminal in- of the current detector is respectively connected to the second end of the eighteenth resistor R18, the second end of the nineteenth resistor R19 and the second end of the twentieth resistor R20, the common end formed by the second ends of the eighteenth resistor R18, the nineteenth resistor R19 and the twenty-third resistor R20 is connected to the high-power device corresponding to the pulse modulation circuit, the eighteenth resistor R18, the nineteenth resistor R19 and the twenty-third resistor R20 are connected to the high-power device corresponding to the pulse modulation circuit, The nineteenth resistor R19 and the twentieth resistor R20 are power resistors, which are used to provide a voltage drop and output after being amplified inside the current detector. The output end of the current detector is respectively connected to the second input end A2 of the fourth comparator and the first input end A1 of the fifth comparator. The first input end A1 of the fourth comparator is respectively connected to the first end of the twenty-first resistor R21 and the first end of the twenty-second resistor R22. The second end of the twenty-first resistor R21 is grounded, and the second end of the twenty-second resistor R22 is connected to the first power supply +5V. The output end Ao of the fourth comparator outputs a current overcurrent BIT signal. If the voltage of the second input end of the fourth comparator is less than the voltage of the first input end, the current overcurrent BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0056] The second input terminal A2 of the fifth comparator is respectively connected to the first end of the twenty-third resistor R23 and the first end of the twenty-fourth resistor R24, the second end of the twenty-third resistor R23 is grounded, and the second end of the twenty-fourth resistor R24 ​​is connected to the first power supply +5V. The output terminal Ao of the fifth comparator outputs a current undercurrent BIT signal. If the voltage of the first input terminal of the fifth comparator is greater than the voltage of the second input terminal, the current undercurrent BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

[0057] Optionally, the external alarm device is an LED lamp, a buzzer or other device with an alarm prompt function.

[0058] It should be noted that each AND gate, comparator, temperature sensor and current detector of the present application adopts existing commercially available modules, which will not be introduced in detail here.

[0059] Compared with traditional transmitters, the all-solid-state transmitter of the present application adopts four-stage amplification and only two sets of power dividers / combiners, which not only simplifies the transmission link and ultimately achieves a power output of more than 400W, but also utilizes a narrower operating frequency band (bandwidth 200MHz) and designs a low-loss 3dB input / output bridge and H-plane waveguide power divider / combiner, which has a higher power combining efficiency. Figure 1 The gain / loss coefficient of each device in the all-solid-state transmitter and the power of each stage are also disclosed, where "+" represents gain and "-" represents loss. According to the measured results, after the transmission excitation signal (3dBm) is amplified by four stages of power using the all-solid-state transmitter of the present application, under the conditions of a transmission pulse width of 500us and a duty cycle of 20%, within the frequency band of 9.3GHz to 9.5GHz, the final output power of the all-solid-state transmitter is 56.6dBm (i.e., 457W), and its synthesis efficiency is improved by 30% compared with that of traditional transmitters.

[0060] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A new type of X-band all-solid-state transmitter, characterized in that: The invention comprises a feeding network and a two-stage GaAs power amplifier, a first amplifying module, a microstrip isolator, a first microstrip coupler, a first coaxial waveguide converter, a second amplifying module, a waveguide dual-directional probe coupler and a waveguide ring / isolator connected in sequence. The input end of the first-stage GaAs power amplifier is used as the input end of the all-solid-state transmitter to access the radio frequency signal, and the output end of the waveguide ring / isolator is used as the output end of the all-solid-state transmitter to connect the antenna port; the feeding network is used to supply power to the two-stage GaAs power amplifier, the first amplifying module and the second amplifying module; the first coaxial waveguide converter is used to convert the microstrip into a waveguide; the tiny radio frequency signal input to the all-solid-state transmitter is amplified by the two-stage GaAs power amplifier, the first amplifying module and the second amplifying module to output a high-power radio frequency signal; The first amplification module includes a 3dB input bridge, a 3dB output bridge and a GaN power amplifier, the input end of the GaN power amplifier I is connected to the first output end of the 3dB input bridge, the input end of the GaN power amplifier II is connected to the second output end of the 3dB input bridge, the input end of the 3dB input bridge is connected to the second-stage GaAs power amplifier, the output end of the GaN power amplifier I is connected to the first input end of the 3dB output bridge, the output end of the GaN power amplifier II is connected to the second input end of the 3dB output bridge, and the output end of the 3dB output bridge is connected to the microstrip isolator; The second amplification module includes a waveguide power divider, a waveguide power combiner, and two second coaxial waveguide converters, an input matching circuit, a GaN power tube, an output matching circuit, a second microstrip coupler, and a third coaxial waveguide converter connected in sequence. The input end of the waveguide power divider is connected to the first coaxial waveguide converter, and the two output ends of the waveguide power divider are respectively connected to the second coaxial waveguide converter. The second coaxial waveguide converter is used to convert the waveguide into a microstrip. The two input ends of the waveguide power combiner are respectively connected to the third coaxial waveguide converter. The third coaxial waveguide converter is used to convert the microstrip into a waveguide. The output end of the waveguide power combiner is connected to the waveguide dual-directional probe coupler.

2. The novel X-band all-solid-state transmitter according to claim 1, characterized in that: The all-solid-state transmitter also includes a pulse modulation circuit, and the voltage distributed and output to the two-stage GaAs power amplifier, the first amplification module and the second amplification module through the feed network is firstly passed through the pulse modulation circuit to achieve negative power-off protection, and then the two-stage GaAs power amplifier, the first amplification module and the second amplification module are powered; The first pulse modulation circuit includes a diode, a triode, a first AND gate, a first driver and a MOS tube. The first input end of the first AND gate is connected to a pulse modulation signal and is also grounded through a first resistor. The second input end of the first AND gate is connected to the anode of the first diode through a second resistor and a third resistor as an enable end of negative power-off protection. The common end of the second resistor and the third resistor is connected to a first power supply. The cathode of the first diode is connected to the cathode of the second diode. The anode of the second diode is connected to the first negative power supply of the feeding network. The base of the triode is connected to the common end of the first diode and the second diode and then to ground through a fourth resistor. The collector of the triode is connected to the second input end of the first AND gate. The emitter of the triode is grounded. The output end is respectively connected to the two input ends of the first driver, and is also grounded through a fifth resistor. The first output end of the first driver is connected to the gate of the second MOS tube, the source of the second MOS tube is connected to the leakage voltage power supply of the two-stage GaAs power amplifier of the feeding network, the drain of the second MOS tube is connected to the second-stage GaAs power amplifier, the second output end of the first driver is connected to the gate of the first MOS tube, the source of the first MOS tube is connected to the first power supply, and the drain of the first MOS tube is connected to the first-stage GaAs power amplifier; if the first negative power supply is powered off, the first AND gate outputs a low level, then the first driver is not turned on, and thus the first MOS tube and the second MOS tube are also not turned on, thereby realizing the negative power-off protection function.

3. The novel X-band all-solid-state transmitter according to claim 2, characterized in that: The second pulse modulation circuit includes a second driver and a third MOS tube, the input end of the second driver is connected to the pulse modulation signal through the sixth resistor, and is also grounded through the sixth resistor and the seventh resistor, the enable end of the second driver is connected to the first negative power supply through the eighth resistor, and is also grounded through the first capacitor, the power supply end of the second driver and the source of the third MOS tube are respectively connected to the leakage power supply of the GaN power amplifier of the feeding network, the power supply end of the second driver is also grounded through the second capacitor and the third capacitor, the output end of the second driver is connected to the gate of the third MOS tube through the ninth resistor, the tenth resistor is connected between the gate and the source of the third MOS tube, and the drain of the third MOS tube is connected to the GaN power amplifier; if the first negative power supply is powered off, the second driver outputs a high level, then the third MOS tube is not turned on, and the negative power off protection function is realized; the pull-down port of the second driver is connected to the drain of the third MOS tube, and the drain of the third MOS tube is quickly discharged; The third pulse modulation circuit includes a third driver and a fourth MOS tube. The connection circuit structure of the third driver and the second driver is the same as that of the input terminal, the enable terminal, the output terminal and the pull-down port. The power supply terminal of the third driver and the source of the fourth MOS tube are respectively connected to the leakage voltage power supply of the GaN power tube of the feeding network, and the power supply terminal of the third driver is also grounded through a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor and a ninth capacitor respectively; if the first negative power supply is powered off, the third driver outputs a high level, and the fourth MOS tube is not turned on, realizing the negative power-off protection function; the pull-down port of the third driver is connected to the drain of the fourth MOS tube, realizing the drain fast discharge function of the fourth MOS tube.

4. The novel X-band all-solid-state transmitter according to claim 2, characterized in that: The all-solid-state transmitter also includes a pulse modulation BIT alarm circuit, including a second AND gate, a third AND gate and a fourth AND gate, wherein the first input end of the second AND gate is connected to the temperature BIT signal, the second input end is connected to the transmission output port standing wave BIT signal, the output end of the second AND gate is connected to the first input end of the fourth AND gate, the first input end of the third AND gate is connected to the current overcurrent BIT signal, the second input end is connected to the pulse modulation input signal, the output end of the third AND gate is connected to the second input end of the fourth AND gate, and the output end of the fourth AND gate outputs the pulse modulation signal; if any one of the temperature BIT signal, the transmission output port standing wave BIT signal, the current overcurrent BIT signal and the pulse modulation input signal is at a low level, then the pulse modulation signal output by the pulse modulation BIT alarm circuit is also at a low level, each of the pulse modulation circuits is not turned on, and the two-stage GaAs power amplifier, the first amplification module and the second amplification module do not work.

5. The novel X-band all-solid-state transmitter according to claim 1, characterized in that: The all-solid-state transmitter also includes a power BIT alarm circuit, including an inductor, a third diode and a first comparator. The anode of the third diode is connected to the output ends of the first microstrip coupler and the second microstrip coupler as the input end of the power BIT alarm circuit, and is also grounded through the inductor. The cathode of the third diode is connected to the first end of the tenth capacitor, the first end of the eleventh resistor and the first input end of the first comparator, respectively. The second end of the tenth capacitor and the second end of the eleventh resistor are both grounded. The second input end of the first comparator is connected to the first end of the twelfth resistor and the first end of the thirteenth resistor, respectively. The second end of the twelfth resistor and the power supply end of the first comparator are respectively connected to the first power supply. The second end of the thirteenth resistor and the ground end of the first comparator are both grounded. The output end of the first comparator outputs a power BIT signal. If the voltage of the first input end of the first comparator is less than the voltage of the second input end, the power BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

6. The novel X-band all-solid-state transmitter according to claim 1, characterized in that: The all-solid-state transmitter also includes a temperature BIT alarm circuit for monitoring high-power devices in the first amplification module and the second amplification module, including a temperature sensor and a second comparator, wherein the temperature sensor is placed close to the high-power devices in the first amplification module and the second amplification module; the first input end of the second comparator is connected to the temperature sensor, the second input end of the second comparator is respectively connected to the first end of the fourteenth resistor and the first end of the fifteenth resistor, the power supply end of the temperature sensor, the second end of the fourteenth resistor and the power supply end of the second comparator are respectively connected to the first power supply, the second end of the fifteenth resistor and the ground end of the second comparator are both grounded, and the output end of the second comparator outputs a temperature BIT signal; if the voltage of the first input end of the second comparator is greater than the voltage of the second input end, the temperature BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

7. The novel X-band all-solid-state transmitter according to claim 5, characterized in that: The all-solid-state transmitter also includes an antenna port matching BIT alarm circuit, including a fourth diode and a third comparator. The second input end of the third comparator has the same connection circuit structure as the first input end of the first comparator. The anode of the fourth diode is connected to the reverse end of the waveguide dual-directional probe coupler as the input end of the antenna port matching BIT alarm circuit. The first input end of the third comparator is respectively connected to the first end of the sixteenth resistor and the first end of the seventeenth resistor. The second end of the sixteenth resistor is grounded, and the second end of the seventeenth resistor is connected to the first power supply. The output end of the third comparator outputs a transmission output port standing wave BIT signal. If the voltage of the second input end of the third comparator is greater than the voltage of the first input end, the transmission output port standing wave BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

8. The novel X-band all-solid-state transmitter according to claim 2, characterized in that: The all-solid-state transmitter also includes a current BIT alarm circuit, including a current detector, a fourth comparator and a fifth comparator, wherein the positive input end of the current detector is respectively connected to the first end of the eighteenth resistor, the first end of the nineteenth resistor and the first end of the twentieth resistor, and the common end formed by the first ends of the eighteenth resistor, the nineteenth resistor and the twenty-third resistor is connected to the pulse modulation circuit, and the negative input end of the current detector is respectively connected to the second end of the eighteenth resistor, the second end of the nineteenth resistor and the second end of the twenty-third resistor, and the common end formed by the second ends of the eighteenth resistor, the nineteenth resistor and the twenty-third resistor is connected to the high-power device corresponding to the pulse modulation circuit. , the eighteenth resistor, the nineteenth resistor and the twentieth resistor are power resistors, the output end of the current detector is respectively connected to the second input end of the fourth comparator and the first input end of the fifth comparator, the first input end of the fourth comparator is respectively connected to the first end of the twenty-first resistor and the first end of the twenty-second resistor, the second end of the twenty-first resistor is grounded, and the second end of the twenty-second resistor is connected to the first power supply, the output end of the fourth comparator outputs a current overcurrent BIT signal, if the voltage of the second input end of the fourth comparator is less than the voltage of the first input end, the current overcurrent BIT signal is abnormal and an external alarm device is connected to prompt an alarm; The second input end of the fifth comparator is respectively connected to the first end of the twenty-third resistor and the first end of the twenty-fourth resistor, the second end of the twenty-third resistor is grounded, and the second end of the twenty-fourth resistor is connected to the first power supply. The output end of the fifth comparator outputs a current undercurrent BIT signal. If the voltage of the first input end of the fifth comparator is greater than the voltage of the second input end, the current undercurrent BIT signal is abnormal and an external alarm device is connected to prompt an alarm.

9. The novel X-band all-solid-state transmitter according to claim 1, characterized in that: The input matching circuit includes an impedance line, a capacitor, a twenty-fifth resistor and a first fan-out line, the first end of the eleventh capacitor is connected to the second coaxial waveguide converter as the input end of the input matching circuit, the second end of the eleventh capacitor is connected to the gate of the GaN power tube as the output end of the input matching circuit, the first impedance line is connected to both ends of the eleventh capacitor, the second end of the eleventh capacitor is connected to the first end of the thirteenth capacitor, the first end of the fourteenth capacitor, the first end of the fifteenth capacitor and the gate voltage power supply of the GaN power tube of the feeding network respectively through the second impedance line, the first fan-out line and the twenty-fifth resistor, and the second ends of the thirteenth capacitor, the fourteenth capacitor and the fifteenth capacitor are all grounded; The output matching circuit includes an impedance line, a capacitor, a twenty-sixth resistor and a second fan-out line. The first end of the twelfth capacitor is connected to the drain of the GaN power tube as the input end of the output matching circuit. The second end of the twelfth capacitor is connected to the second microstrip coupler as the output end of the output matching circuit. The third impedance line is connected to both ends of the twelfth capacitor. The first end of the twelfth capacitor is connected to the first end of the twenty-sixth resistor, the first end of the seventeenth capacitor, the first end of the eighteenth capacitor and the second pulse modulation circuit / third pulse modulation circuit respectively through the fourth impedance line and the second fan-out line. The second end of the twenty-sixth resistor is connected to the first end of the sixteenth capacitor. The second ends of the sixteenth capacitor, the seventeenth capacitor and the eighteenth capacitor are all grounded. The input matching circuit and the output matching circuit realize impedance matching of the input and output of the GaN power tube.

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