A receiver final stage amplifier with high third-order intermodulation suppression and intermodulation suppression method

Abstract

A receiver final stage amplifier with high third-order intermodulation suppression and an intermodulation suppression method, including a 90° branch line bridge, a first 50Ω load resistance, a first amplifier, a second amplifier, an attenuator, a phase shifter, and a 90° coupler and a second 50Ω load resistor. The realization of the final stage amplifier in the present invention adds the second amplifier on the basis of the traditional single-stage medium power amplifier (the first amplifier), the second amplifier is a small signal amplifier, and the 1dB compression point is lower as 10~12dBm, and its output The signal has the characteristics of low main carrier power but high third-order intermodulation power. The two amplifiers are cascaded using a 90° branch line bridge at the input end, and are cascaded through a 90° coupler at the output end. The attenuator and phase shifter complete the adjustment of the amplitude and phase of the third-order intermodulation signal output by the second amplifier. The adjustment makes the third-order intermodulation products produced by the two amplifiers achieve equal amplitude and anti-phase at the synthesis end so as to realize power cancellation.

Description

technical field [0001] The invention relates to a receiver final-stage amplifier with high third-order intermodulation suppression and an intermodulation suppression method, belonging to the technical field of microwave circuits. Background technique [0002] With the continuous development of satellite technology and the continuous increase of satellite communication capacity, the system puts forward higher and higher requirements for the linearity of satellite-borne microwave receivers. Specifically, the satellite-borne microwave receiver is required to have good third-order intermodulation suppression performance at a relatively high input level. Usually, the third-order intermodulation suppression performance of the whole receiver is mainly determined by the third-order intermodulation suppression performance of the final stage amplifier of the receiver. [0003] The third-order intermodulation suppression performance of spaceborne microwave receiver is related to the i...

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Problems solved by technology

[0004] The technical problem solved by the present invention is: to overcome the deficiencies in the prior art, provide a receiver final stage amplifier with high third-order intermodulation suppression and an intermodulation suppression method, and focus on solving the third-order intermodulation of the existing satellite-borne microwave receiver final stage amplifier restricted question

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