Directional Coupler RF Power Measurement Despite Port Mismatch
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Solution Overview
Problem
Existing methods for determining RF transmit power in semiconductor devices, such as MMICs, are inaccurate due to non-ideal directional couplers and unmatched output structures, leading to errors in power measurements during production and runtime.
Innovation Solution
A method and semiconductor device utilizing a directional coupler with forward and reverse ports, coupled with power level detectors, measure signal power at different frequencies to calculate transmit power by averaging measurements and correcting for reflection coefficients, allowing accurate power determination independent of coupler directivity and mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional directional couplers are used for RF transmit power measurement, then the measurement setup is simple, but the measurement precision deteriorates due to non-ideal coupler characteristics and mismatches
Solution Approach 1:
The patent segments the measurement process into multiple frequency point measurements. Instead of relying on a single broadband measurement that is sensitive to coupler imperfections, the system divides the frequency range into discrete points and performs measurements at each point. This segmentation allows for more precise determination of transmit power by averaging results across multiple frequency points, thereby reducing the impact of non-ideal coupler characteristics on overall measurement accuracy.
2Measurement precision
If measurements are performed at multiple frequency points, then the measurement precision improves, but the measurement time increases
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing the relationship between frequency points and expected measurement results during the setup phase. The system预先 determines the optimal frequency points to measure and prepares the averaging algorithm in advance. This preliminary preparation allows the actual measurement process to execute efficiently, reducing the time penalty associated with multi-frequency measurements while maintaining high precision through the pre-planned measurement strategy.
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
Enables precise and cost-effective RF transmit power measurement during production and runtime, reducing errors caused by non-ideal couplers and unmatched structures.
Implementation Method 1
the directional coupler is configured to couple to the forward port a first portion of a signal received at the input port and wherein the directional coupler is configured to couple to the reverse port a second portion of a signal received at the output port
Implementation Method 2
determining, for each RF signal of the set of RF signals transferred to the directional coupler, measurement information indicating at least one of a signal power measured at the reverse port or a signal power measured at the forward port
Data Source
AI summary
A method includes controlling an RF transmitter to generate a set of RF signals, each RF signal having a frequency value from a set of frequency values, transferring each RF signal to an input port of a directional coupler, the direction coupler including the input port, an output port, a forward port, and a reverse port, wherein the directional coupler is configured to couple to the forward port a first portion of a signal received at the input port, and couple to the reverse port a second portion of a signal received the output port, determining, for each RF signal, measurement information indicating a signal power measured at the reverse port and/or a signal power measured at the forward port to generate a set of measurement values, and determining information indicating an RF transmit power associated with the RF transmitter based on the set of measurement values.