Six-Port Spatial Electromagnetic Wave Measurement

A new method for measuring free-space electromagnetic waves, based on a scalar interferometric measurement principle similar to the six-port concept, is presented. A proof of concept was performed at frequency band 6-12 GHz. The corresponding measurement system contains both a reference channel featuring a transmitting antenna directly irradiating receiving antenna, and, a test channel which has a transmitting antenna irradiating a test object. A wave reflected or scattered by the test object, and the reference wave phase shifted in several steps, both coherent, interfere in the receiving antenna. Redundancy is exploited via a multistate regime of measurement which enables to reduce uncertainty of measurement. A geometrical representation of the approach in the complex plane makes it possible to estimate measurement uncertainties. Precise computing of uncertainties based on the Monte Carlo Method is also performed.