Multi-port S-parameter Measurement via Segmented 2-Port Access
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Solution Overview
Problem
Conventional methods for measuring scattering parameters of N-port linear networks require simultaneous access to all ports, which is impractical due to the need for multiple connections and disconnections, especially when ports are close or difficult to access.
Innovation Solution
An apparatus and method that calculate scattering parameters based on measured electrical responses at one or more ports, allowing other ports to face a reflection coefficient with an amplitude of 0.5 or larger, eliminating the need for termination with a resistance close to the reference impedance, and enabling access to only two ports during measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to measure scattering parameters of N-port networks, then measurement accuracy is maintained, but the complexity of the measurement setup and the difficulty of accessing all ports simultaneously increases significantly
Solution Approach 1:
The patent divides the N-port network measurement into multiple 2-port measurement steps. Instead of measuring all ports simultaneously, the method segments the measurement process into sequential 2-port measurements, where different combinations of two ports are measured in separate steps. This reduces the complexity of the measurement setup at any given time while maintaining overall measurement accuracy through mathematical reconstruction of the complete N-port scattering matrix.
Solution Approach 2:
The patent applies preliminary termination to ports that are not currently being measured. Before each 2-port measurement, the remaining N-2 ports are terminated with matching impedances to prevent reflections from affecting the measurement. This preliminary action ensures that each 2-port measurement is isolated and accurate, enabling the reconstruction of the complete N-port scattering matrix from sequential measurements.
2Loss of information
If all ports are accessed simultaneously for measurement, then complete scattering parameter data is obtained, but the measurement process becomes impractical for closely spaced or hard-to-reach ports
Solution Approach 1:
The measurement process is segmented into multiple steps, each accessing only two ports at a time. This segmentation makes the measurement process practically operable for networks with closely spaced or hard-to-reach ports, as the physical accessibility requirements are dramatically reduced compared to simultaneous N-port access.
Solution Approach 2:
The patent uses mathematical feedback to reconstruct the complete N-port scattering matrix from the sequential 2-port measurements. The measured 2-port S-parameters are combined using matrix operations to calculate the complete N-port scattering parameters, ensuring that no information is lost despite the segmented measurement approach.
3Loss of information
If multiple connections and disconnections are required for port access, then complete measurement coverage is achieved, but the measurement time and operational complexity increase
Solution Approach 1:
The measurement is segmented into multiple 2-port steps, which reduces the number of connections and disconnections required compared to attempting to access all N ports simultaneously. Each step requires minimal reconfiguration, and the segmented approach enables systematic data collection that can be automated.
Solution Approach 2:
The patent maintains continuity of useful action by systematically progressing through different 2-port combinations without complete disconnection and reconnection. The measurement process continues with minimal interruption, using the results from previous steps to inform subsequent measurements, thereby reducing total measurement time while ensuring complete data coverage.
Data Source
AI summary
This invention relates to an apparatus, a method and a computer program for calculating one or more scattering parameters of a linear network, the network including a number of N ports adapted to provide electric connections. The apparatus is configured to calculate, and the method includes calculating, one or more scattering parameters of the linear network, which are related to a reference impedance, on the basis of a measured electrical response at one or more ports of the linear network to an incident wave applied at a port of the linear network, measured under the condition that one or more of other ports of the linear network face a reflection coefficient Γ with an amplitude ρ of 0.5 or larger. The computer program is adapted to perform such a method and runs on a computer.