Transistor Switch Biasing for Low-Harmonic RF Power Switching
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Solution Overview
Problem
Existing high power semiconductor switches in RF communication systems face challenges in reducing spurious harmonic emissions and improving linearity, despite achieving high isolation and low insertion loss.
Innovation Solution
The method involves biasing transistor switches with specific on-state and off-state voltage levels, where the off-state voltage level is set below the on-state level by a sufficient amount to control spurious harmonic emissions and maintain acceptable linearity, using a biasing controller architecture that adjusts gate and source-drain voltages to achieve optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high power semiconductor switches are used to achieve high isolation and low insertion loss, then switch performance is improved, but spurious harmonic emissions increase and linearity deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the off-state voltage level to be below the on-state level by a specific amount. This voltage parameter optimization reduces spurious harmonic emissions and improves linearity while maintaining high isolation and low insertion loss, resolving the contradiction between switch performance and harmful emissions.
2Object-generated harmful factors
If off-state voltage level is reduced to lower spurious harmonic emissions, then harmful emissions are reduced, but linearity may deteriorate
Solution Approach 1:
The patent optimizes the voltage parameter by setting the off-state level below the on-state level by a carefully determined amount. This specific parameter adjustment simultaneously reduces spurious harmonic emissions and maintains acceptable linearity, resolving the contradiction between reducing harmful emissions and maintaining signal fidelity.
Data Source
AI summary
A system and method are provided for biasing transistor switches in a semiconductor based high power switch. Off-state Vgsd biasing for the off transistor switches is based upon acceptable levels of spurious harmonic emissions and linearity.