Adaptive Impedance Switch Circuit for Power-Off Return Loss
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Solution Overview
Problem
Conventional signal transceivers experience performance degradation due to low return loss when operating in a power-off state, as the return loss decreases significantly compared to the power-on state, affecting system performance.
Innovation Solution
An adaptive impedance switch circuit is introduced between the band-pass filter and the front-end module, comprising an input terminal, output terminal, voltage input circuit, frequency resonant circuit, and bias circuit, which adjusts impedance values to enhance return loss during power-off states by switching between conducted and non-conducted states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the signal transceiver operates in power-off state, then power consumption is reduced, but return loss deteriorates (decreases by 3.4 dB)
Solution Approach 1:
The impedance switch circuit is pre-configured with switching elements that can be activated before the power-off state to establish appropriate impedance matching. The circuit includes switching elements coupled to nodes between the band-pass filter and front-end module, which can be controlled to maintain proper impedance even when the main signal path is powered down.
Solution Approach 2:
The impedance switch circuit acts as an intermediary component between the band-pass filter and the front-end module. It includes switching elements with control terminals that can be independently controlled to maintain impedance matching without requiring the main signal path to be active, thus preserving return loss during power-off states.
2Reliability
If the impedance switch circuit is added, then return loss is improved (increased by up to 9 dB), but device complexity increases
Solution Approach 1:
The impedance switch circuit changes the electrical parameters (impedance values) at key nodes in the signal path. By controlling the switching elements, the circuit can transform the impedance characteristics to maintain proper matching between the band-pass filter and front-end module, achieving up to 9 dB improvement in return loss without requiring complete redesign of the existing architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The adaptive impedance switch circuit effectively increases the minimum return loss by 9 dB between the band-pass filter and front-end module, and 0.5 dB between the connector and coaxial cable within the specified frequency band, thereby maintaining or improving system performance even in power-off states.
Implementation Method 1
a frequency resonant circuit coupled to the input terminal and the voltage input circuit for adjusting the impedance value
Implementation Method 2
a bias circuit coupled between the output terminal and a node connected by the input terminal, the voltage input circuit and the frequency resonant circuit for converting a voltage value of the signal
Data Source
AI summary
A signal transceiver includes a connector for receiving a signal, a band-pass filter coupled to the connector for filtering the signal, a front-end module for demodulating the signal and an adaptive impedance switch circuit coupled between the band-pass filter and the front-end module for switching an impedance value between the band-pass filter and the front-end module.