Dual tone approach for unambiguous six-port based interferometric distance measurements

This publication shows an approach for absolute, unambiguous distance measurements with a Six-Port radar at 24 GHz. Such an interferometric radar has the drawback of ambiguity problem concerning phase, limiting the measuring distance to half of the used wavelength. This can be solved with the presented dual tone system using the resulting beat frequency between two tones to determine an absolute position within even several wavelengths. In the following, this system will be presented along with simulations and measurements proving the concept.