Design feed antenna Ka/ Q-band based on “repairable” scheme

In the article an operation principal of polarization frequency-selective device is presented which is based on “repairable scheme” composed of two joined orthomode selectors for dividing transmit-receive frequencies. The polarization frequency-selective device, being engineered according to this scheme was implemented in the feed antenna allows to ensure the transmitting and receiving signals with circular polarization over the Ka/Q-bands. The role of frequency-selective device in feed horn performs an orthomode selector for selecting which of transceiver signals and polarization components. One of the most common structures orthomode broadband selector is a cross-converter branching. This cross-splitter is a waveguide of circular cross section, which is perpendicular to the axis connecting the four mutually perpendicular rectangular waveguide. Connections of this waveguides occurs through transformers complex shape to provide better conformance with the waveguide of circular cross section. This type of selector has the structure possesses some symmetry properties, which make system of broadband. Using of cross-splitter as orthomode selector allowed to expand the operating bandwidth. Through the introduction of various irregularities in the construction of this selector able to separate low and high frequency components of the frequency spectrum and to achieve suppression of spurious higher modes. Recovering the second signal is provided with a combined orthomode first selector by four U-shaped waveguide sections. Introduction to the design of high-frequency selector on the output polarizer, implemented on a circular waveguide with a groove, and the low-frequency output of the septum polarizer, allowed for the release of data polarizers transmit / receive signals with circular polarization. Using this principle of construction of frequency selector allows to divide transmit-receive frequencies to save from necessary using if extra separate feed antenna. Measured electrical characteristics developed feed antenna according to the contemporary requirements which are demanded for feed antenna of satellite communication systems.