Ku wave band tracking radar radio frequency STC circuit

Abstract

The invention discloses a ku wave band tracking radar radio frequency STC circuit which comprises a current limiting resistor, a voltage filter capacitor, a feed inductor, a first blocking coupling capacitor, a second blocking coupling capacitor, a first PIN diode and a second PIN diode. One end of the current-limiting resistor is used as a control power supply voltage input port. The other end of the first blocking coupling capacitor is connected with one end of the voltage filter capacitor and one end of the feed inductor, the other end of the voltage filter capacitor is grounded, the other end of the feed inductor is connected with one end of the first blocking coupling capacitor, the positive electrode of the first PIN diode and the positive electrode of the second PIN diode, and the other end of the first blocking coupling capacitor serves as a radio frequency signal port. The negative electrodes of the first PIN diode and the second PIN diode are grounded, the positive electrode of the second PIN diode is connected with one end of the second blocking coupling capacitor, and the other end of the second blocking coupling capacitor serves as a radio frequency signal port. The direct connection loss is small, and the influence on the noise coefficient is extremely small.

Description

technical field [0001] The invention belongs to the technical field of radar, in particular to a radio frequency STC circuit for Ku-band tracking radar. Background technique [0002] Tracking radar receivers generally use STC (gain time control) circuits to realize the ability of the gain of the receiving link to change with time, that is, the gain is inversely proportional to the distance of the tracked target, so as to avoid the radar when the whole machine tracks close-range targets. When the gain is too high, the noise floor rises, or when the gain is too low, the echo signal of the target signal is too small, resulting in unstable tracking. [0003] The existing STC circuit technology is generally divided into radio frequency STC circuit and intermediate frequency STC circuit according to its position in the receiver circuit. The advantage of the former is that the STC circuit can improve the input dynamic range of the receiving link in the front stage of the receiver. ...

AI Technical Summary

Problems solved by technology

However, the pass-through loss of the RF voltage-controlled attenuator is generally above 0.5dB, and the pass-through loss of the RF multi-digit digital control attenuator is generally above 2dB. Therefore, when designing the radar receiving front end, in order to obtain a lower receiver noise figure, the voltage A controlled attenuator or a multi-bit digitally controlled attenuator is placed after the first-stage low-noise amplifier to realize the STC function, but this will cause the saturation of the echo signal of the close-range target, thereby distorting the distance information

However, if a voltage-controlled attenuator or a multi-bit numerically controlled attenuator is placed before the first-stage low-noise amplifier to realize the STC function, the attenuator's pass-through loss will be superimposed on the receiver noise figure, causing the receiver system sensitivity decline

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