Small-signal, complex distortion and waveform measurement system for multiport microwave devices

Abstract

This paper presented a general-purpose multiport measurement system and calibration algorithm for the characterizations of N-port microwave devices. The system is built around the micro wave transition analyzer as a multi-harmonic receiver from DC to 40 GHz, which provides the system with the scope capability for time domain measurements and the vector network analyzer capabilities for frequency-domain measurements. The developed system has the capability of measuring the S-parameters of linear microwave circuits as well as the AM-AM and AM-PM conversions for nonlinear microwave devices in single-step measurements, without any need for reconnection or change in the calibration technique or meas urement setup. The system can accurately quantify the impact of crosstalk on the performance of the multiport nonlinear microwave systems in terms of power efficiency and signal distortion. The proposed calibration algorithm for waveform measurements utilizes a standard signal frequency generator and does not rely on the use of a multi-harmonic generator to calculate the error box parameters at the fundamental and harmonic frequencies. The algorithm is also applicable to any multi-harmonic phase-locked receiver based measurement system. Finally, it has been demonstrated that the measurement system is capable of performing waveform engineering measurements. The comparison of waveforms obtained in 50 Ω and non-50 Ω impedance environments using the developed system and standard commercial scopes shows good agreement. This enhances confidence in the measurement data obtained from the developed measurement system.