Parametric characterization of six-port interferometer demodulator through mixer modeling

Functional parameters of six-port demodulator are studied in this paper. Indeed, noise figure (NF), conversion loss and inter-modulation products, which are the key parameters of a mixer, are derived through theoretical analysis and validated by simulations. In order to reduce the conversion loss while keeping the power detector´s working condition in the square law region and maintain the benefits of low-power LO, the detector biasing technique is also investigated. Also, by modeling the six-port interferometer as a mixer, a platform of extracting a set of equivalent mixer parameters through circuit simulations is proposed. As a case study, the proposed technique is applied to extract the mixer model of a six-port interferometer demodulator operating in E-band with a commercial diode of Avago HSCH-9161. Such a modeling technique provides RF receiver designers a quantitative way of understanding the six-port interferometer demodulators and comparing them with traditional mixer-based zero-IF demodulators.