radar transmitter

The radar transmitter must not only be able to generate the peak and average power required to detect the desired target at the maximum range , And it should be able to generate the signal with appropriate waveform and stability required for a specific application . The transmitter can be an oscillator or an amplifier , But the latter usually has more advantages .
Many types of power sources have been used in radar . Magnetron power oscillator was very popular in a period , But now it is almost not used except for civil navigation radar . Due to the relatively low average power of magnetron (1-2kW) And poor stability , It is necessary to detect small moving targets in long-range strong clutter , Other power sources are usually more appropriate . Magnetron power oscillator is an example of quadrature field transistor . Related to it are the quadrature field amplifiers used in some radars in the past , But it is also limited in important radar applications , Especially when it is necessary to detect moving targets in clutter . High power klystron and traveling wave tube , Is an example of a linear electron beam tube . Radar often uses such tubes at high power , Both have the appropriate large bandwidth and stability for Doppler processing , So it has been very popular .
Solid state amplifier , For example, transistors , It is also used in radar , Especially in phased radar . Although the power of a single transistor is low , However, each of the multiple radiating units of the array antenna can utilize multiple transistors to achieve the high power required by many radar applications . When using transistor amplifiers , The radar shall be designed as a pulse that can work on the high duty cycle required by the equipment . therefore , The use of solid-state transmitters will have an impact on other parts of the radar system . In millimeter wave band, gyrotron can be used as amplifier or oscillator to obtain high power . For a long time , Grid control vacuum tube at UHF And low frequency radar , However, there is less and less interest in lower frequency radar .
Although not everyone will deliberately , Some radar system engineers have a choice , Klystron amplifier will be considered as the first choice of high-power modern radar , If its use is appropriate for the application .
notes ： The article is excerpted from 《 Radar manual 》 The third edition