Symmetric-Reciprocal-Match Method for Vector Network Analyzer Calibration

TL;DR

This paper introduces the symmetric-reciprocal-match (SRM) method for VNA calibration, utilizing symmetric loads and reciprocal devices to improve accuracy with fewer fully defined standards.

Contribution

The SRM method offers a novel calibration approach that reduces the need for fully specified standards by leveraging symmetry and reciprocity properties.

Findings

Numerical simulations confirm high accuracy of SRM method.

Experimental measurements with commercial standards validate the approach.

Only the match standard needs to be fully defined in SRM.

Abstract

This paper proposes a new approach, the symmetric-reciprocal-match (SRM) method, for calibrating vector network analyzers (VNAs). The method involves using multiple symmetric one-port loads, a two-port reciprocal device, and a matched load. The load standards consist of two-port symmetric one-port devices, and at least three unique loads are used. However, the specific impedances of the loads are not specified. The reciprocal device can be any transmissive device, although a non-reciprocal device can also be used if only the one-port error boxes are of interest. The matched load is fully defined and can be asymmetric. We numerically demonstrated the proposed method's accuracy with synthetic data and with measurements of coaxial standards using a commercial short-open-load-reciprocal (SOLR) calibration kit with verification standards. An advantage of the proposed method is that only the match standard is defined, whereas the remaining standards are partially defined, either through symmetry or reciprocity.