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Free electrons in the ionosphere lead to significant group delay dispersion for signals in the megahertz and low gigahertz range. A novel microwave filter is presented that is capable of compensating for the non-linear ionospheric…

天体物理仪器与方法 · 物理学 2013-05-03 Paul Roberts

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous…

In the present study, a measurement setup utilizing mm-wave transceivers with steerable directive antennas, mounted on both a customized UAV and a ground station has been used to study Air-to-Ground (A2G) radio links and, more generally,…

Transmittance fluctuations in turbulent atmospheric channels result in quadrature excess noise which limits applicability of continuous-variable quantum communication. Such fluctuations are commonly caused by beam wandering around the…

We report on the diffraction-free propagation of space-time wave packets (STWPs) -- a class of propagation-invariant pulsed beams -- for $\sim\!1$ km in an open-air laser range in a low-turbulence scenario. Making use of $\approx\!100$-fs…

Dispersion engineering of microring resonators is crucial for optical frequency comb applications, to achieve targeted bandwidths and powers of individual comb teeth. However, conventional microrings only present two geometric degrees of…

光学 · 物理学 2023-07-12 Gregory Moille , Xiyuan Lu , Jordan Stone , Daron Westly , Kartik Srinivasan

In this paper, we analyze both the rate of convergence and the performance of a matched-filter (MF) precoder in a massive multi-user (MU) multiple-input-multiple-output (MIMO) system, with the aim of determining the impact of distributing…

信息论 · 计算机科学 2015-03-04 Peter J. Smith , Callum T. Neil , Mansoor Shafi , Pawel A. Dmochowski

In a distributed multi-antenna system, multiple geographically separated transmit nodes communicate simultaneously to a receive node. Synchronization of these nodes is essential to achieve a good performance at the receiver. RadioWeaves is…

信息论 · 计算机科学 2021-12-02 Unnikrishnan Kunnath Ganesan , Rimalapudi Sarvendranath , Erik G. Larsson

We demonstrate a remote microwave/radio-frequency (RF) transfer technique based on the stabilization of a fiber link using a fiber-loop optical-microwave phase detector (FLOM-PD). This method compensates for the excess phase fluctuations…

光学 · 物理学 2014-03-25 Kwangyun Jung , Junho Shin , Jinho Kang , Stephan Hunziker , Chang-Ki Min , Jungwon Kim

We explore routing of propagating phonons in analogy with previous experiments on photons. Surface acoustic waves (SAWs) in the microwave regime are scattered by a superconducting transmon qubit. The transmon can be tuned on or off…

量子物理 · 物理学 2020-04-16 M K Ekström , T Aref , A Ask , G Andersson , B Suri , H Sanada , G Johansson , P Delsing

We present experimental results on a model system for studying wave propagation in a complex medium exhibiting low frequency resonances. These experiments enable us to investigate a fundamental question that is relevant for many materials,…

经典物理 · 物理学 2015-05-20 V. Leroy , A. L. Strybulevych , J. H. Page , M. G. Scanlon

We consider nanonodes randomly distributed in a circular area and characterize the received signal strength when a pair of these nodes employ molecular communication. Two communication methods are investigated, namely free diffusion and…

A spatially reconfigurable antenna arrays consists of an antenna array of finite length and fixed geometry which is displaced within a given area. Using these reconfigurable components, the performance of MIMO systems is remarkably improved…

信息论 · 计算机科学 2017-04-24 Saba Asaad , Ali Bereyhi , Mohammad Ali Sedaghat , Ralf R. Müller , Amir M. Rabiei

Fast and broadband spectrum sensing is an essential component in cognitive radio systems, intelligent transportation systems, electronic warfare systems, etc. However, traditional electronic-based solutions have a trade-off among the…

光学 · 物理学 2024-09-25 Taixia Shi , Chi Jiang , Chulun Lin , Fangyi Yang , Yiqing Liu , Fangzheng Zhang , Yang Chen

Systems of small distributed satellites in low Earth orbit (LEO) transmitting cooperatively to a multiple antenna ground station (GS) are investigated. These satellite swarms have the benefit of much higher spatial separation in the…

信号处理 · 电气工程与系统科学 2021-12-17 Maik Röper , Bho Matthiesen , Dirk Wübben , Petar Popovski , Armin Dekorsy

One of the cornerstones of quantum communication is the unconditionally secure distribution of classical keys between remote parties. This key feature of quantum technology is based on the quantum properties of propagating electromagnetic…

In the spatial channel models used in multi-antenna wireless communications, the propagation from a single-antenna transmitter (e.g., a user) to an M-antenna receiver (e.g., a Base Station) occurs through scattering clusters located in the…

信息论 · 计算机科学 2019-10-31 Yi Song , Mahdi Barzegar Khalilsarai , Saeid Haghighatshoar , Giuseppe Caire

The comparison of optical reference frequency signals over free-space optical links is limited by the relative motion between local and remote sites. For ground to low earth orbit comparison, the expected Doppler shift and Doppler rate…

In this paper, the capacity of wireless channels is characterized based on electromagnetic and antenna theories with only minimal assumptions. We assume the transmitter can generate an arbitrary current distribution inside a spherical…

信息论 · 计算机科学 2016-11-17 Wonseok Jeon , Sae-Young Chung

Radio frequency wireless power transfer (WPT) enables charging low-power mobile devices without relying on wired infrastructure. Current existing WPT systems are typically designed assuming far-field propagation, where the radiated energy…

信号处理 · 电气工程与系统科学 2021-10-12 Haiyang Zhang , Nir Shlezinger , Francesco Guidi , Davide Dardari , Mohammadreza F Imani , Yonina C Eldar