Octave Bandwidth Compact Turnstile-Based Orthomode Transducer

Abstract

A 64% instantaneous bandwidth scalable turnstile-based orthomode transducer to be used in the so-called extended C-band satellite link is presented. The proposed structure overcomes the current practical bandwidth limitations by adding a single-step widening at the junction of the four output rectangular waveguides. This judicious modification, together with the use of reduced-height waveguides and E-plane bends and power combiners, enables to approach the theoretical structure bandwidth limit with a simple, scalable and compact design. The presented orthomode transducer architecture exhibits a return loss better than 25 dB, an isolation between rectangular ports better than 50 dB and a transmission loss less than 0.04 dB in the 3.6-7 GHz range, which represents state-of-the-art achievement in terms of bandwidth.

Novel Compact Waveguide Dual Circular Polarizer

“…The Sparameters for the turnstile OMT in Ref. [24][25][26][27][28] are also found to be different from the structure presented here. where n is an nonnegative integer, when the waves reflected from the shorted Ports of 3 and 4 arrives at the central area, they will have a phase difference of 180 • , which means two opposite incident phases.…”

“…However, we will demonstrate that the S-parameter for the OMTs described in Ref. [24][25][26][27][28] is significantly different from that for the design presented here. The design goal of the Scattering-Matrix for the six modes is the following: there is no mode excited in the circular waveguide when the higher order mode (i.e., TM 01 ) is cutoff in the circular waveguide.…”

Design of a 70–116 GHz W-band turnstile OMT

“…Electroforming may be used, as in [9], which avoids the need for sectioning the block, but complexity is shifted to the mandrel as the closed regions require special machining (such as wire-EDM). In [10]- [12], the OMT is machined in quarters and the sectioning planes follow the E and H-planes of the circular waveguide. Another approach is to section the OMT in planes that are transverse to the circular input and along the natural seams of the output rectangular waveguides [13]- [17].…”

Dual-Band Ortho-Mode Transducer With Irregularly Shaped Diaphragm

“…They are usually used to receive dual-polarized signals from a horn antenna and separate them into two independent ports. To realize wide-band performance, symmetrical structures are usually employed, such as Bφifot junction and turnstile junction [1][2][3]. Recently, with the growth of communication applications, it is preferred to receive and transmit orthogonally polarized signals simultaneously through a single antenna, which covers more than one frequency band.…”