Scattering Coefficient Measurement Using Scalar Power Meter
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Solution Overview
Problem
High-frequency electronic circuit measurements face challenges in accurately determining reflection and transmission coefficients due to increased costs and complexity of vector network analyzers (VNAs) as frequency rises, leading to difficulties in precision and signal purity.
Innovation Solution
A method and apparatus that use a scalar measuring instrument to determine scattering coefficients by superimposing multiple vector signals on reflected or transmitted waves, allowing conversion of scalar measurements into vector values without requiring phase information, thereby reducing instrument size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vector network analyzer (VNA) is used to accurately measure scattering coefficients at high frequencies, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The measurement system is segmented into separate functional components: a simple scalar power meter for magnitude measurement, and a separate phase measurement system that adds phase information only when needed. This segmentation allows the basic measurement function to remain simple while providing accurate vector measurement capability when required.
Solution Approach 2:
An intermediary processing system is introduced that takes scalar power measurements and combines them with phase information from a phase meter to reconstruct vector scattering coefficients. This intermediary layer enables accurate vector measurement without requiring the entire measurement chain to be a complex vector network analyzer.
2Adaptability or versatility
If the frequency of measurement is increased to meet high-frequency circuit requirements, then adaptability to high-frequency applications is improved, but measurement precision deteriorates due to frequency conversion losses
Solution Approach 1:
The frequency conversion and mixing stages that cause signal purity degradation are extracted from the measurement path. The system uses direct scalar power measurement at the measurement frequency without requiring frequency conversion, thereby maintaining signal purity while enabling high-frequency operation.
Solution Approach 2:
The traditional mechanical/electronic frequency conversion system (mixers, local oscillators) is replaced with a computational approach that processes scalar power measurements to derive vector information, eliminating the sources of frequency conversion loss and signal degradation.
3Reliability
If multiple electric-power measuring instruments are used to measure four electric powers for reflection, then measurement completeness is improved, but device size and cost increase
Solution Approach 1:
A single scalar power meter is designed to perform multiple measurement functions by measuring different power levels in sequence. The instrument measures incident power, reflected power, and forward power using the same hardware, thereby providing complete measurement capability with a single instrument rather than requiring multiple specialized meters.
Solution Approach 2:
The measurement process uses periodic switching to measure different power components at different time instances. The scalar power meter sequentially measures incident power, reflected power, and forward power in a periodic cycle, thereby obtaining complete measurement data through time-multiplexed operation rather than requiring simultaneous measurement with multiple instruments.
Data Source
AI summary
A measuring method and measurement system that includes a signal source that applies a signal to a device under test, a scalar measuring instrument that measures a reflected wave reflected from the device under test or a transmitted wave transmitted through the device under test as a scalar value, and a superimposing signal system that superimposes three different vector signals whose relation values are specified in advance on the reflected wave or the transmitted wave of the device under test. The three vector signals are superimposed on the reflected wave or the transmitted wave of the device under test, and the superimposed signals are each measured as a scalar value by the electric-power measuring instrument. The three measured scalar values are converted into a single vector value using the specified relation values of the three vector signals, thereby obtaining a transmission coefficient of the device under test.