Bidirectional Coupler Reflected Power Measurement
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Solution Overview
Problem
Existing directional couplers in communication systems have limited accuracy in measuring reflected power due to finite directivity, leading to inaccurate protection of power amplifiers and other components from high levels of reflected energy and affecting linear amplification.
Innovation Solution
A method using a bidirectional coupler with S-parameters to accurately determine the amplitude and phase of output reflected signals by measuring coupled forward and reverse signals, and electrical transmission parameters, allowing for more precise monitoring of reflection coefficient and VSWR, thereby enhancing the protection of power amplifiers and ensuring linear amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a directional coupler is used to monitor reflected power, then the power amplifier can be protected from high reflected energy, but the measurement accuracy is limited by finite directivity causing inaccurate monitoring
Solution Approach 1:
The patent segments the reflected power measurement into two separate measurement paths: one for forward power and one for reverse power. By using separate measurement chains with independent directional couplers and detectors, the system achieves more accurate reflected power measurement by eliminating the directivity limitation of a single coupler.
Solution Approach 2:
The patent introduces an intermediary calculation process that uses S-parameters to mathematically separate the forward and reverse power components. The system measures total power and uses known S-parameters to calculate the reflected power component, acting as a mathematical intermediary to overcome the physical limitation of finite directivity.
2Measurement precision
If the reflected power monitoring accuracy is improved, then better protection of power amplifier and components is achieved, but the device complexity increases
Solution Approach 1:
The patent makes the monitoring system multi-functional by enabling it to perform both forward power monitoring and reflected power monitoring using a unified measurement architecture. The same measurement chain is used for both purposes, reducing overall system complexity while maintaining high measurement accuracy through the S-parameter based calculation method.
Data Source
AI summary
Techniques are provided to more accurately determine reflected power, reflection coefficient, and/or voltage standing wave to permit prompt protection of components such as power amplifiers and notify communication system operators. This is accomplished by more accurately determining an amplitude and phase of an output reflected signal at an output port of a bidirectional coupler as a function of the following: an amplitude and a phase of a coupled forward signal coupled into a forward coupled port of the bidirectional coupler; an amplitude and a phase of a coupled reverse signal coupled into a reverse coupled port of the bidirectional coupler; an electrical transmission parameter from an input port of the bidirectional coupler to the forward coupled port; an electrical transmission parameter from the input port to the reverse coupled port; and an electrical transmission parameter from an output port of the bidirectional coupler to the reverse coupled port.