"Passive Components for Broadband Millimeter-wave Receivers."
Oscar A. Peverini
IEIIT-CNR, c/o Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
High performance broadband millimeter-wave receivers demand a variety of waveguide passive components, such as filters, directional couplers, ortho-mode transducers, polarizers, marker-injectors. All these components must satisfy stringent requirements in terms of bandwidth, insertion-loss, channel isolation and equalization. In this contribution, Ka-band prototypes of any of these components, which have been developed in the framework of ASI (Italian Space Agency)-funded projects devoted to astrophysical observations, will be reported. The results concerns OMTs with a measured isolation higher than 60 dB, polarizers with cross-coupling terms lower than -50 dB, 12-cavity filter with return loss better than 30 dB in a 10% bandwidth. For each component, we will describe the methods of analysis, design and experimental characterization. In particular, a synthesis technique will be shown, which yields directly the geometry filters, directional couplers and polarizers with bandwidth up to 30 %, without any need of optimization stages. Finally, a measurement procedure for the complete characterization of dual-polarized antenna feed systems will be reported.