K band inter-stage mismatch type low noise amplifier

Abstract

The invention discloses a K band inter-stage mismatch type low noise amplifier. The low noise amplifier can be applied to a Ka band satellite communication system. The K band inter-stage mismatch type low noise amplifier disclosed by the invention comprises: a waveguide probe containing an air transition cavity, a preceding stage of the low noise amplifier is composed of two inter-stage mismatch microwave transistors, an active bias provides a static bias voltage for the microwave transistors, and a backward stage of the low noise amplifier is composed of an MMIC single amplifier. A coaxial waveguide probe conversion structure in the low noise amplifier comprises an air transition cavity, and the transition cavity can expand the working bandwidth of wave conversion and can assist the assembly and positioning of the probe at the same time; the two microwave transistors adopt a mismatch design, a backward stage tube is used as the load of the preceding stage, and the preceding stage tube works at the minimal noise working point through the allocation of a mismatch impedance inverter circuit; and the active bias can provide constant drain electrode working voltage and current for the microwave transistors in high and low temperature environments to guarantee the stability of the electric properties thereof.

Description

technical field [0001] The invention relates to the field of microwave technology, and relates to a low-noise amplifier technology applied to Ka-band satellite communication equipment. Background technique [0002] At present, in the fields of communication, remote sensing and remote control, radar, electronic countermeasures, and radio astronomy, low-noise amplifiers have become an indispensable part of the receiving front end of their electronic systems. The main function of the low noise amplifier is to amplify the signal under the condition of introducing lower noise, and its noise figure index determines the sensitivity of the communication system to a large extent. [0003] In the Ka-band satellite communication system, the receiving frequency of the satellite communication ground station is 20 GHz; due to the high frequency, the loss and rain attenuation of electromagnetic wave transmission are relatively large, which puts forward a higher noise figure for the low noi...

AI Technical Summary

Problems solved by technology

Discrete circuits can achieve a sufficiently low noise figure, but the gain is low, and the transistor input and output matching circuit occupies a large area, making it difficult to miniaturize the circuit; microwave monolithic integrated circuits are small in size and high in gain, but their noise figure is poor

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