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Return loss
About: Return loss is a research topic. Over the lifetime, 11090 publications have been published within this topic receiving 97603 citations.
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TL;DR: In this article, the authors presented the results of a parametric study devised to allow them to optimally design a patch fed planar dielectric slab waveguide extended hemi-elliptical lens antenna.
Abstract: We present the results of a parametric study devised to allow us to optimally design a patch fed planar dielectric slab waveguide extended hemi-elliptical lens antenna. The lens antenna, 11lambda times 13lambda in the lens plane and 0.6lambda thick, constructed from polystyrene and weighing only 90 g is fabricated and characterized at 28.5 GHz for both single and multiple operating configurations. The lens when optimized for single beam operation achieves 18.5 dB measured gain (85% aperture efficiency), 40deg and 4.1deg half power beam width for E plane and H plane respectively and 10% impedance bandwidth for -10 dB return loss. While for optimized for multiple beam operation it is shown that the lens can accommodate up to 9 feeds and that beam symmetry can be maintained over a scan angle of 27deg with a gain of 14.9 to 17.7 dB, and first side lobe levels of -11 to -7 dB respectively. Over the frequency range 26 to 30 GHz the lens maintains a worst case return loss of -10 dB and port to port feed isolation of better than -25 dB. Further it is shown that residual leaked energy from the structure is less than -48 dBm at 1 cm, thus making a low profile enclosure possible. We also show that by simultaneous excitation of two adjacent ports we can obtain difference patterns with null depths of up to -36 dB.
33 citations
TL;DR: In this paper, a turnstile-based waveguide orthomode transducer has been proposed for the WR75 standard rectangular waveguide, which exhibits a return loss better than 23 dB at any port, an insertion loss less than 0.06 dB, and an isolation of 50 dB over the full bandwidth.
Abstract: A >40p bandwidth fully scalable turnstile-based waveguide orthomode transducer having excellent phase performance is described for the WR75 standard rectangular waveguide. Flexible bandwidth tuning is achieved through the use of an interchangeable stepped scattering element. Reduced height waveguide topology provides a simple, compact, and robust design against mechanical tolerances. The intrinsic broadband nature of half-height E-plane bends and single-step power combiners assures high order mode free increased bandwidth in balanced phase operation. The designed orthomode transducer exhibits a return loss better than 23 dB at any port, an insertion loss less than 0.06 dB, and an isolation of 50 dB over the full bandwidth. Moreover, the phase difference between orthogonal polarizations is lower than 0.7° over the band, thus enabling applications where phase-matched outputs are required. This design has been chosen for the QUIJOTE cosmic microwave background experiment due to its cost-effective, compact design, and high-quality performance as well as being readily scalable to the WR51 and WR28 waveguide bands. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.
33 citations
Journal Article•
TL;DR: In this article, a simple orthomode transducer suitable for operation from centimeter to submillimeter wavelengths with appropriate scaling is described, which operates over a 1.3:1 frequency band, narrower than a full waveguide band (typically 1.5:1).
Abstract: We describe a simple orthomode transducer suitable for operation from centimeter to submillimeter wavelengths with appropriate scaling. It is fabricated as a split-block assembly with all waveguides in the same plane, and requires no septum or polarizing wires. The OMT operates over a 1.3:1 frequency band, narrower than a full waveguide band (typically 1.5:1). For a WR-10 version of the OMT, covering 78-102 GHz, the polarization isolation is > 37 dB and the return loss at the rectangular waveguide ports > 24 dB. The practical upper frequency for this design is probably limited by the precision of alignment that can be achieved between the block halves, which affects the polarization isolation.
33 citations
TL;DR: In this article, an effective methodology to design a compact four-element multiple-input-multiple-output (MIMO) antenna with high performance over ultra-wide bandwidth (BW) is presented and discussed.
Abstract: In this study, an effective methodology to design a compact four-element multiple-input-multiple-output (MIMO) antenna with high performance over ultra-wide bandwidth (BW) is presented and discussed. Taking the advantages of symmetry of most planar ultra-wideband (UWB) antennas, an asymmetric feeding scheme technique is utilised to chop a previously developed UWB slot antenna with overall dimensions of 30 mm × 30 mm into two halves to yield a more compact structure while retaining its overall frequency- and time-domain performances. Benefiting from orthogonal orientation, a compact UWB MIMO antenna system is arranged using four half-sized elements. The proposed MIMO antenna has an overall size of 40 mm × 40 mm and exhibits impedance BW from 2.94 to more than 14 GHz (10 dB return loss) with port isolation better than 17 dB over the entire operating band without using any decoupling structures. This is achieved via the inherent directional radiation properties of slot antenna elements and their asymmetrical placements. Envelope correlation coefficient is computed, and it is within the acceptable limit, which validates the design concept for building a compact MIMO antenna system with good performance.
33 citations
TL;DR: In this article, the authors proposed an integration of the telecommu- nication system within garment and wearable product known as textile antenna, which provides a wide operating band satisfying an ultrawideband application of 3.1-10.6 GHz at 10 dB return loss.
Abstract: This research proposed an integration of the telecommu- nication system within garment and wearable product known as textile antenna. Such antenna performances on bending and wet conditions are discussed in the manuscript. This embroidered antenna provides a wide operating band satisfying an ultrawideband application of 3.1-10.6 GHz at 10 dB return loss. The proposed antenna is developed from a simple circular with T-slot structure and a partial ground plane. The fabricated textile antenna was made from both conductive and nonconductive wear- able materials. The simulated and measured bend angles of 20 � ,3 0 � , 40� ,5 0 � ,6 0 � ,7 0 � , and 80� is analyzed in terms of reflection coefficient via computer simulation technology software and programmable network analyzer, respectively. Moreover, the proposed embroidered antenna performance in wet conditions are investigated in four states of antenna inside water, antenna immediately wet, antenna approximately dry, and antenna completely dry. Simulated and measured results of reflection coefficient, surface current distribution, and gain are presented to vali- date the usefulness of the presented design. V C 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2158-2163, 2014; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28527
33 citations