Optimized 90° Polarization Shift Step Twists for Ku, K and Ka Bands

Abstract

Optimized models for 90°polarization shift step twists for Ku, K and Ka bands are presented. The cross-section of the waveguide employed is similar to that of a rectangular one, with the difference that the walls of the shorter side are part of a circular one with the proper diameter. The optimized models have been found using the CST Microwave Studio simulation tool and in all cases the return loss is kept below -20 dB for a wide range of frequency spectrum. Two examples are given, one for Ku band and the other for K and Ka ones.

Multi-Section Bow-Tie Steps for Full-Band Waveguide Polarization Rotation

“…Twists with arbitrary rotation angles can also be obtained by an alternate cascade of rectangular and circular waveguides [8]. Other alternatives, eliminating the circular sections are [1], [2], [9], [10], based on modifications of the rectangular waveguide walls.…”

Arbitrary-Angle Single-Step Waveguide Twist for Quasi-Octave Bandwidth Performance

“…An approach to a more compact solution is the concatenation of a different number of quarterwavelength-like sections with specific angular offset between them [2][3][4][5][6]. These works can be easily adjusted in order to get an arbitrary polarization rotation angle, but they rely on the number of sections to obtain a wide bandwidth with good return and insertion losses; therefore, they may also result in long solutions in terms of wavelength.…”

Design of a Compact Broadband 90° Waveguide Twist Based on Double-Corner-Cut Square Slots

“…Also, their rigorous curve structure makes them difficult and costly in manufacturing. In order to decrease the twists' volume and longitudinal length, step twisting of waveguides is well documented in literature [2][3][4][5][6]. In [4], a circular waveguide is inserted into two adjacent steps to improve impedance bandwidth.…”