Determination of microwave phase and amplitude from power measurements

Although straightforward in principle, the extension of existing designs for automatic network analyzers (ANA´s) to the higher microwave frequencies is difficult in the current state of the art. What appears to be needed is a basically different approach to the microwave detection problem. One promising alternative is provided by the so-called “six-port” techniques, which eliminate the need for modulation or for frequency conversion, local oscillators, phase detectors, etc. Recent theoretical studies have provided new insights into the basic concept and lead to “five-port” configurations which require three instead of four amplitude detectors. Of particular interest is the projected measurement dynamic range of 50–60 dB corresponding to a dynamic range requirement in the amplitude detectors of a nominal 20 dB or less.