Quasi-Octave Bandwidth In-Phase Three-Layer Platelet Orthomode Transducer Using Improved Power Combiners

Cano, Juan Luis; Mediavilla, A.

doi:10.1109/lmwc.2018.2874160

Cited by 11 publications

(9 citation statements)

References 14 publications

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“…It is a turnstile-junction-based OMT, which has been assembled in a platelet configuration with three layers. 31 The input port of the OMT is a circular waveguide with a diameter of 9.41 mm and the two rectangular waveguides at the output are rectangular waveguides with a ¼ 15.4 mm and b ¼ 7.7 mm. The OMT machined in aluminum is shown in Fig.…”

Section: Orthomode Transducermentioning

confidence: 99%

10- to 19.5-GHz microwave receiver of an electro-optical interferometer for radio astronomy

Aja

Fuente

Artal

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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This document describes the analysis, design, and prototype test results of the microwave section of a 10-to 19.5-GHz interferometer, aimed at obtaining polarization data of cosmic microwave background (CMB) radiation from the sky. First, receiver analysis is thoroughly assessed to study the contribution of each subsystem when obtaining the Stokes parameters of an input signal. Then, the receiver design is detailed starting from the front-end module, which works at cryogenic temperature, composed of a set of passive components: feedhorn, orthomode transducer, and polarizer, together with active components, such as very low-noise amplifiers. The back-end module (BEM) is directly connected, working at room temperature for further amplification, phase switching, and correlation of the signals. Moreover, the whole frequency band is split into two sub-bands (10 to 14 GHz and 16 to 20 GHz) using a high selective diplexer in the BEM in order to reject radiofrequency interferences. Phase switches allow phase difference steps of 5.625 deg, which modulate the correlated outputs to reduce systematic effects in the postdetection signal processing. Finally, measurements of all the subsystems comprising the microwave section of the receiver as well as the characterization of the complete microwave receiver are presented. The obtained results demonstrate successful performance of the microwave receiver that, together with an electro-optical correlator and a near-infrared camera, comprises the interferometer. Moreover, synthesized images corresponding to combinations of the Stokes parameters can be obtained with the whole system.

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Section: Orthomode Transducermentioning

confidence: 99%

10- to 19.5-GHz microwave receiver of an electro-optical interferometer for radio astronomy

Aja

Fuente

Artal

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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“…These types of structures have been made in both traditional waveguide and substrate integrated waveguide topologies [1]- [13]. These OMTs combine two or more waveguide paths into a common waveguide by bending orthogonal guides together [9], using a series of matching structures [4], [7], [8], probe feeding a horn from multiple points [12], through waveguide turnstiles [1]- [3], [6], [10], or other balanced structures [5], [13] where the common waveguide is fed symmetrically with pairs of single polarization waveguides.…”

Section: Introductionmentioning

confidence: 99%

“…However, this asymmetric feed can result in an asymmetric ration pattern this was observed in [8] where two rectangular waveguides were brought into the corner of a horn antenna, or in [9] where two orthogonal paths were bent together, both producing asymmetric far-field patterns. Waveguide turnstiles, among other applications like circulators, can be used to combine two orthogonally polarized paths into a common guide in a balanced fashion [1], [2], [6], [10], [11], [14]- [17]. These types of structures feed each of the co-polarized paths with a power divider and phase matched lengths of waveguide to create a two port device (one for each of the orthogon paths) that feeds the common guide with symmetrically.…”

Section: Introductionmentioning

confidence: 99%

3-D Printed Dually Symmetric Orthomode Transducer and Horn Antenna at X-Band

Goode

Saavedra

2023

IEEE Open J. Antennas Propag.

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A dually symmetric orthomode transducer (OMT) and horn antenna are presented for both single port linearly polarized operation and dual port circular polarization use. The feed uses two waveguide splitters and a feed bend to feed a four-port horn antenna that has the two groups of ports orthogonal to each other to produce a symmetric radiation pattern. The feed is printed from 316L stainless steel while the horn is printed from a plastic polymer and metallized using aluminum tape. The structure is based on WR 90 waveguide and covers the guide's full operating band of 8.2 GHz to 12.4 GHz. Peak realized gain values of 20.5 dBi were measured with cross polarization rejection of over 40 dB. Here linearly polarized and circularly polarized results are presented, the latter using an off-the-shelf hybrid to control the phase for the two ports. Enabled by the symmetric feed, both the linear and circularly polarized radiation patterns were highly symmetric.

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“…The physical symmetry of the OMT structure determines the amount of excited higher‐order modes and restricts the maximum theoretical bandwidth of operation . For the radio astronomy application, wideband OMTs are needed, several types of which have been presented in previous works well suited for wideband specifications …”

Section: Introductionmentioning

confidence: 99%

“…A novelty double‐ridged waveguide OMT operating at 16‐26 GHz 46.5% bandwidth is described, which solves the high insertion loss problem with the quad‐ridge at this frequency band by using two‐ridge waveguide to coaxial waveguide transition . Turnstile‐based OMT is an excellent one because it inherently has high isolation between orthogonal ports, and can be matched over a wide bandwidth . However, the turnstile junction OMT treats the two polarizations equally and needs two recombination networks, resulting in a more bulky structure especially in the transversal plane.…”

Section: Introductionmentioning

confidence: 99%

Wideband orthomode transducer for the Square Kilometre Array band4 single pixel feed

Wang

Yang

2019

Int J RF Microw Comput Aided Eng

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The design of a compact wideband orthomode transducer (OMT) for band4 single pixel feed of the Square Kilometre Array (SKA) dish is presented. The geometry of the proposed OMT is based on circular quad-ridged waveguide to obtain wideband characteristics, which consists of a coaxial to quad-ridged waveguide transition and a circular to quad-ridged waveguide tapered transition. By adopting circular quadridged waveguide and high-order cosine taper for the ridges, the length of OMT is compact and the levels of higher-order modes generated at the circular waveguide aperture are lower. To verify the OMT performance, a prototype is manufactured and tested using a vector network analyzer. The measured results agree very well with the calculated ones across the frequency range 2.8-5.18 GHz. The tested reflection coefficients are less than -19 dB, the insertion losses are less than 0.25 dB for both polarization channels, and the isolation between two output ports is better than 37.7 dB. It is confirmed that the designed OMT can be satisfied with the requirement of the SKA band4 feed system. K E Y W O R D Sorthomode transducer, quad-ridged waveguide, Square Kilometre Array, wide band

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Quasi-Octave Bandwidth In-Phase Three-Layer Platelet Orthomode Transducer Using Improved Power Combiners

Cited by 11 publications

References 14 publications

10- to 19.5-GHz microwave receiver of an electro-optical interferometer for radio astronomy

10- to 19.5-GHz microwave receiver of an electro-optical interferometer for radio astronomy

3-D Printed Dually Symmetric Orthomode Transducer and Horn Antenna at X-Band

Wideband orthomode transducer for the Square Kilometre Array band4 single pixel feed

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