Matching the Antenna-Feeder System in Differential-Gated Polarimeters on Microwave and Extremely-High Frequencies

While creating the precision differential-gated polarimeters for the analysis of the structure of small-scale polarized microwave and extremely-high-frequency radiations, increased requirements are imposed for matching such antenna-feeder systems as parabolic reflector antennas, exciting horns, and turnstile polarization converters. Matching the parabolic reflector antennas to polarization converters is realized by using horns with anisotropic conductivity of walls. In the paper, the conditions of the high-quality matching of the exciting horns to antennas are discussed; the characteristics of six exciting horns are calculated and experimentally determined for four bands of microwave and extremely-high frequency radiations. The two-element matching post in the turnstile junction was calculated by means of the edge finite-elements method and dimensions of the matching post elements that provide minimum reflection in the circular and rectangular waveguides were found. The efficiency of the performed calculations is confirmed by experimental studies, which resulted in small values of the reflection coefficient and the low level of cross-polarized field components in the setup with two antenna-feeder systems in the 3 cm wave band.