A 90 GHz-band monoblock type waveguide orthomode transducer

Abstract

This paper presents a 90GHz-band waveguide orthomode transducer (OMT) which is composed of a short circuited circular common waveguide and two branching rectangular waveguides dug through a metal block. An analysis and design of the OMT are performed using full wave modematching techniques. A 90GHz-band OMT fabricated with the aid of the analysis and design technique has realized excellent performances.

A Manufacturing-Oriented 90 GHz Ortho-Mode Transducer for a Polarimetric Experiment

“…The septum length was properly chosen in order to minimise the coupling between the two channels and to avoid any impairment by weakly coupled resonances of the waveguide following the septum. With respect to an UMT without septum, like the one reported in [10], the present solution allows bandwidth enlargement and improved isolation control; as a drawback, it adds some manufacturing difficulties.…”

“…However, the above contributions have referred to designs developed for frequencies considerably lower than the 90 GHz band. Only a couple of works [10,11] have appeared so far for devices operating in this frequency band; unfortunately, the structure adopted in [10] is intrinsically narrow-band, while the solution presented in [11] is not satisfactory for the isolation. The latter realisation is manufactured from electroformed copper and requires to introduce a very thin (25 pim) septum after manufacturing.…”

Theory and Experiment of a Compact Waveguide Dual Circular Polarizer

“…Thus, turnstile OMT is not compact and the two waveguide rings may decrease the final bandwidth. The compact three-port branching OMT [17] composed by two H-plane rectangular waveguides coupled with a common circular waveguide uses two bottle-neck-like irises to match the structure and realize the isolation, whose return loss < −10 dB had a bandwidth < 12%, and isolation < −35 dB with a bandwidth > 10%. Other kind of circular polarizers such as microstrip polarizer [18][19][20][21][22][23][24] also have the disadvantage of narrow bandwidth and low efficiency due to losses of conductor, dielectric and surface wave.…”

A design of novel grooved circular waveguide polarizers

“…mentioned coupling characteristics of branch Waveguide; to numerically obtained coupling characteristics of grooved circular waveguides in the following full-wave analysis As shown in Fig.1, the grooved circular waveguide is composed of two key-building block elements, that is, a circular-to-rectangular waveguidc cross-junction and two short-circuit rectangular waveguides. We perform an accurate design of the presented polarizer using full-wave analysis of circular-torectangular waveguide H-plane and E-plane crosz:-junctions which expands the mode-matching method for circular-to-rectangular waveguide WE-plane T-junctions associated with the generalized S-matrix technique [5].…”

“…And further, we propose a convenient design method of the grooved circular waveguide polarizer, which applies the well-known design method of the branch waveguide coupler [3,4]. The design method is accurately performed using 111-wave mode-matching techniques for circular-torectangular waveguide cross-junctions [5]. A Ka-band grooved circular waveguide polarizer fabricated with the aid of the analysis and design technique has realized excellent performances without tuning elements.…”