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A circularly polarized leaky-wave antenna capable of frequency scanning is proposed in this paper. The main objective is to achieve high gain and polarization purity without the need for a complex feed network. The antenna consists of two…

Applied Physics · Physics 2020-07-21 Ali Mohammad Hakimi , Ali Keivaan , Homayoon Oraizi , Amrollah Amini

Multi-mode antennas are an alternative to classical antenna arrays, and hence a promising emerging sensor technology for a vast variety of applications in the areas of array signal processing and digital communications. An unsolved problem…

Signal Processing · Electrical Eng. & Systems 2019-05-30 Sami Alkubti Almasri , Robert Pöhlmann , Niklas Doose , Peter A. Hoeher , Armin Dammann

The calibration and analysis of polarization observations in Very Long Baseline Interferometry (VLBI) requires the use of specific algorithms that suffer from several limitations, closely related to assumptions in the data properties that…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Ivan Marti-Vidal , Alejandro Mus , Michael Janssen , Pablo de Vicente , Javier Gonzalez

Wi-Fi access points have been widely deployed in homes, offices, and public spaces. Some APs allow users to adjust the antenna orientation to improve communication performance by optimizing antenna polarization. However, it is difficult for…

Networking and Internet Architecture · Computer Science 2026-01-27 Akihito Taya , Yuuki Nishiyama , Kaoru Sezaki

We have developed a 230 and 345 GHz very-long-baseline interferometry (VLBI) receiver for the South Pole Telescope (SPT). With the receiver installed, the SPT has joined the global Event Horizon Telescope (EHT) array. The receiver optics…

Instrumentation and Methods for Astrophysics · Physics 2018-09-25 Junhan Kim , Daniel P. Marrone

This paper considers the problem of accurate measurement of circular polarization in imaging spectral-line VLBI observations in the lambda=7 mm and lambda=3 mm wavelength bands. This capability is especially valuable for the full…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 A. J. Kemball , L. Richter

The response of an interferometer changing its orientation with respect to a fixed reference frame is given in terms of the beam-pattern factors and the polarization-averaged antenna power pattern.

General Relativity and Quantum Cosmology · Physics 2015-06-25 G. Giampieri

Planar Orthomode Transducers (OMTs) are commonly used for polarization measurements at millimeter wavelengths. We present an optical coupling study of an octave bandwidth planar OMT in circular waveguide based on 3D electromagnetic…

Instrumentation and Methods for Astrophysics · Physics 2022-09-02 Johannes Hubmayr , Jason E. Austermann , James A. Beall , Jake A. Connors , Shannon M. Duff , Jeffrey J. McMahon

Adaptation of a wireless system to the polarization state of the propagation channel can improve reliability and throughput. This paper in particular considers polarization reconfigurable multiple input multiple output (PR-MIMO) systems,…

Information Theory · Computer Science 2024-04-04 Paul S. Oh , Sean S. Kwon , Andreas F. Molisch

If the linear polarization of the cosmic microwave background (CMB) is rotated in a frequency-independent manner as it propagates from the surface of last scatter, it may introduce a B-mode polarization. Here I show that measurement of…

Astrophysics · Physics 2009-04-08 Marc Kamionkowski

The multimode waveguide bends (MWBs) with very compact sizes are the key building blocks in the applications of different mode-division multiplexing (MDM) systems. To further increase the transmission capacity, the silicon multimode…

Optics · Physics 2023-08-09 Juanli Wang , Shangsen Sun , Runsen Zhang , Fengchun Zhang , Ning Zhu

Photonic devices exhibiting all-optically reconfigurable polarization dependence with a large dynamic range would be highly attractive for active polarization control. Here, we report that strongly polarization-selective nonlinear…

Optics · Physics 2019-02-20 Dae Seok Han , Il-Min Lee , Kyung Hyun Park , Myeong Soo Kang

Millimeter-wave (mmWave) systems use directional beams to support high-rate data communications. Small misalignment between the transmit and receive beams (e.g., due to the mobility) can result in significant drop of the received signal…

Signal Processing · Electrical Eng. & Systems 2018-02-13 Dalin Zhu , Junil Choi , Qian Cheng , Weimin Xiao , Robert W. Heath

Light-fidelity (LiFi) is a networked optical wireless communication (OWC) solution for high-speed indoor connectivity for fixed and mobile optical communications. Unlike conventional radio frequency wireless systems, the OWC channel is not…

Information Theory · Computer Science 2018-10-01 Mohammad Dehghani Soltani , Ardimas Andi Purwita , Zhihong Zeng , Harald Haas , Majid Safari

LiteBIRD, a forthcoming satellite mission, aims to measure the polarization of the Cosmic Microwave Background (CMB) across the entire sky. The experiment will employ three telescopes, Transition-Edge Sensor (TES) bolometers and rotating…

Millimeter-wave (mmWave) bands will be used for the fifth generation communication systems to support high data rates. For the proper characterization of the mmWave propagation channel, it is essential to measure the power angular-delay…

Signal Processing · Electrical Eng. & Systems 2019-07-31 Fatih Erden , Ozgur Ozdemir , Wahab Khawaja , Ismail Guvenc

I discuss the physics of polarization in models with early reionization. For sufficiently high optical depth to recombination the polarization is boosted on large scales while it is suppressed on smaller scales. New peaks appear in the…

Astrophysics · Physics 2016-08-30 Matias Zaldarriaga

Laser guide stars with adaptive optics allow astronomical image correction in the absence of a natural guide star. Single guide star systems with a star created in the earth's sodium layer can be used to correct the wavefront in the near…

Astrophysics · Physics 2009-11-11 S. Rabien , F. Eisenhauer , R. Genzel , R. I. Davies , T. Ott

While conventional imaging in VLBI provides information only about the relative position between different features of a given source, phase-referenced observations can provide precise positional information with respect to an external…

Astrophysics · Physics 2007-05-23 Eduardo Ros

In this paper, a novel concept of a leaky-wave antenna is proposed, based on the use of Huygens' metasurfaces. It consists of a parallel-plate waveguide in which the top plate is replaced by a bianisotropic metasurface of the Omega type. It…

Applied Physics · Physics 2018-11-09 Elena Abdo-Sánchez , Michael Chen , Ariel Epstein , George V. Eleftheriades