Room-temperature semiconductor maser and applications thereof

A microwave ranging system, comprising a master station instrument and a passive slave station instrument;

• wherein:
• the master station instrument comprises a signal source, an isolator, a power amplifier, a duplexer, a low-noise amplifier, a frequency detector and a master station instrument antenna;
• when in use, the signal source generates a microwave signal;
• the microwave signal is passed through the isolator and is then input into the power amplifier for amplification;
• the amplified signal is input into a first passband port of the duplexer;
• a main port of the duplexer is connected to the master station instrument antenna;
• a signal output from a second passband port is input into the low-noise amplifier;
• and a passive frequency conversion signal from the slave station instrument is amplified by the low-noise amplifier and then input into the frequency detector to detect the frequency;
• and
• the passive slave station instrument comprises a slave station instrument antenna and a passive frequency conversion device;
• when in use, the slave station instrument antenna receives a signal from the master station instrument and transmits a frequency conversion signal generated by the passive frequency conversion device;
• the passive frequency conversion device comprises a first matching network, a second matching network, a heterojunction-containing transistor and a resonant network;
• an output end of the first matching network is connected to a drain of the heterojunction-containing transistor;
• an input end of the second matching network is connected to a source of the heterojunction-containing transistor;
• a gate of the heterojunction-containing transistor is grounded by the resonant network;
• and, the microwave signal transmitted by the master station instrument antenna is fed into the passive frequency conversion device.

A wireless DC-free sensing information transmission circuit, comprising a transceiving antenna, a drain matching circuit, an open-circuited line, a sensor, a heterojunction-containing transistor and a resonant network, wherein one end of the drain matching circuit is connected to the transceiving antenna while the other end thereof is connected to a drain of the heterojunction-containing transistor, and a source of the heterojunction-containing transistor is connected to the open-circuited line;

• when in use, a modulated microwave signal generated by transition of polaritons is reflected to the drain matching circuit and transmitted by the transceiving antenna;
• a gate of the heterojunction-containing transistor is grounded by the resonant network;
• an output end of the sensor is connected between the drain matching circuit and the heterojunction-containing transistor;
• and, the drain matching circuit receives pumped microwaves through the transceiving antenna, and transmits the microwave signal modulated by sensing information to the transceiving antenna.

A reflective microwave amplifier, comprising:

• a circulator, a source matching network, a pump matching network, a heterojunction-containing transistor, and a tuning network, wherein:
• the circulator is connected to an input end, an output end and an input end of the source matching network;
• an output end of the source matching network is connected to a source of the heterojunction-containing transistor;
• a gate of the heterojunction-containing transistor is grounded by the tuning network;
• and the pump matching network is connected to a drain of the heterojunction-containing transistor;
• and
• when in use, an input signal is passed to the source matching network through the circulator and is then matched by the source matching network and fed into the heterojunction-containing transistor;
• pumped microwaves are fed into the heterojunction-containing transistor through the pump matching network, so that polaritons in the energy level of the heterojunction-containing transistor are excited to a higher energy level;
• the tuning network adjusts the resonant frequency according to the frequency of the signal to be amplified, so that the input signal is amplified at a maximum amplification factor at low-noise;
• and, the amplified signal is passed through the source matching network and is then output from the output port of the circulator, thereby amplifying the power of the input signal.

A pass-type microwave amplifier, comprising:

• an input matching network, a heterojunction-containing transistor, a drain matching network, a tuning network, a duplexer, a pump matching network, and an output matching network, wherein:
• the input matching network is connected to a source of the heterojunction-containing transistor, a gate of the heterojunction-containing transistor is grounded by the tuning network, and a drain of the heterojunction-containing transistor is connected to one end of the drain matching network;
• the other end of the drain matching network is connected to a general port of the duplexer;
• two branched ports of the duplexer are connected to the pump matching network and the output matching network, respectively;
• and
• when in use, an input signal is matched by the input matching network and then fed into the heterojunction-containing transistor;
• pumped microwaves are passed through the pump matching network and are then fed into the heterojunction-containing transistor, so that polaritons in the energy level of the heterojunction-containing transistor are excited to a higher energy level;
• the tuning network adjusts the resonant frequency according to the frequency of the signal to be amplified, so that the polaritons excited to the higher energy level transition to a lower energy level specified by the resonant frequency of the tuning network so as to radiate energy;
• due to the frequency of the input signal, stable excited radiation will occur during the transition of the polaritons excited to the higher energy level to the specified energy level, so that the signal is amplified at low-noise;
• and, the amplified signal is output by the output matching network.