Calibrating Network Analyzer Measurement Holder Using 15-Parameter Model
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Solution Overview
Problem
Current calibration methods for network analyzers, particularly those using the 16-term error model, require identical reflection coefficients at the input and output of the measurement holder, which is difficult to achieve, and need exact transmission behavior of transmissive standards, making them technically challenging or impossible to implement effectively.
Innovation Solution
A method that uses four non-transmissive calibration standards and one transmissive calibration standard to determine 15 linear-in-T parameters, allowing for the calculation of all scattering parameters of a measurement holder, with the option to freely select one system error for scaling, enabling calibration and characterization without the need for exact transmissive standard behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current calibration methods using the 16-term error model are applied, then system errors can be determined, but identical reflection coefficients at input and output of the measurement holder are required which is difficult to achieve
Solution Approach 1:
The patent changes the calibration parameters from requiring identical reflection coefficients to using arbitrary reflection coefficients at input and output. The method determines 15 linear-in-T parameters that fully characterize the measurement holder without requiring symmetric boundary conditions, thereby resolving the contradiction between measurement precision and ease of manufacture
Solution Approach 2:
The patent segments the error model into 15 independent linear-in-T parameters that can be determined separately through measurement of known standards. This segmentation allows each parameter to be characterized independently without requiring the entire system to satisfy the restrictive condition of identical reflection coefficients, making calibration more practical while maintaining accuracy
2Measurement precision
If transmissive calibration standards are used, then transmission behavior can be characterized, but exact transmission behavior is required which makes implementation technically challenging or impossible
Solution Approach 1:
The patent extracts the transmission characterization from the restrictive requirement of exact transmissive standard behavior. By determining 15 linear-in-T parameters through a combination of non-transmissive and transmissive standards, the method separates the transmission characterization from the need for perfectly known transmissive standards, thereby improving reliability while maintaining measurement precision
Solution Approach 2:
The patent uses partial transmissive standards where only the essential transmission characteristics are required rather than exact complete characterization. The 15-parameter model allows transmission behavior to be determined with less stringent requirements on the transmissive standards, making implementation more reliable while still achieving accurate measurement
Data Source
AI summary
A method and a system for calibrating a measuring arrangement on the basis of a 16-term error model determines a matrix (A) with measured scattering parameters (Sm) from different calibration standards (3) and with associated actual scattering parameters (Sa) of the calibration standards (3) and determines linear-in-T system errors (Ti) for the calibration of a network analyzer (1) by solving a linear equation system with the determined matrix (A). To solve the linear equation system, a first and a second linear-in-T system error (k, p) are freely selected in each case. With use of reciprocal calibration standards, the determined linear-in-T system errors are weighted with the freely selected first linear-in-T system error (Ti) or with a correct second linear-in-T system error pkor(k)) dependent upon the first linear-in-T system error (k).