Compact multiport reflectometer for microwave material characterization

Abstract

In this project, a simple, innovative, and compact three-probe reflectometer has been developed. The reflectometer can be used to find the complex reflection coefficient of an unknown device under test over a relatively broad frequency range based on the three measured power amplitudes of the three probes. The designed three-probe reflectometer is expected to provide results comparable to those provided by a commercial vector network analyser. Besides simple, the main advantage of this threeprobe reflectometer is that it only involves scalar amplitude measurements and no phase-shift measurements, whereby it has less electronic circuit component requirements and reduces the cost of the electronic components, as well as it is insensitive to the operating temperature. The main contribution of this work is that the operating bandwidth of the reflectometer has been improved by optimizing the distance or space position between the three probes along the transmission line. Besides that, a calibration process was designed to eliminate systematic errors of reflectometer.