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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Impact of Linear Mode Coupling on the Nonlinear Transmission Performance of Few-Mode Fibres
摘要： In this paper, we review the study of nonlinear transmission performance of few-mode fibre links operating for different linear mode coupling regimes and for different mode delay maps. We will describe how linear mode coupling and differential mode delay can be used to mitigate the overall nonlinear distortion and present optimum link configurations at practical levels of digital equalisation complexity.
关键词： linear mode coupling,differential mode delay,nonlinear analysis,few-mode fibres
更新于2025-09-04 15:30:14
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UHF Reader Antenna for Near and Far-Field RFID Operation
摘要： In order to detect the RFID tags kept inside an enclosure, the reader antenna can couple energy into another antenna kept in the near-field region. To detect the tags placed in the far-field, the reader antenna should have a good gain. Usually, these two requirements compete with each other due to the effect of coupling on the frequency of operation of the antenna system. In this work modification to a loop antenna is proposed such that it can operate in both near and far-field. Loop antenna with high impedance surface (HIS) reflector results in a low-profile antenna pair where both the antennas can interchangeably operate in near-field and far-field, with their operating frequency band independent of the spacing between the antennas. The performance of the proposed antennas is compared with that of several other antennas by measuring the read range of RFID tags. It is found that the proposed antennas perform better in comparison with the other antennas when detecting the tags placed inside an enclosure. When operating as a far-field antenna, their performance is very close to that of a conventional RFID reader antenna which is optimized only for far-field operation.
关键词： near-field coupling,far-field near-field antenna,RFID,UHF,high impedance surface,loop antennas
更新于2025-09-04 15:30:14
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DESIGN OF NOVEL COMPACT TRI-BAND BANDPASS FILTER WITH CONTROLLABLE FREQUENCIES AND HIGH SELECTIVITY
摘要： This paper presents a compact tri-band bandpass ?lter (BPF) with high selectivity. The proposed ?lter utilizes novel stub-loaded quarter-wavelength resonators and conventional uniform quarter-wavelength resonators. The latter is embedded in the former, and they are separated by a feed line. Due to these quarter-wavelength resonators, the total size is greatly reduced. Moreover, the passband frequencies can be controlled individually. To enhance its selectivity, source-load coupling is employed. For demonstration, an experimental ?lter is implemented. High skirt selectivity and suppression levels are observed in the measured results. The circuit area of the ?lter is 0.17λg × 0.19λg, featuring compact size.
关键词： high selectivity,compact size,stub-loaded quarter-wavelength resonators,tri-band bandpass filter,source-load coupling
更新于2025-09-04 15:30:14
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The Effect of Antenna Mutual Coupling on MIMO Radar System Performance
摘要： Multiple-input multiple-output (MIMO) radar systems use orthogonal signaling to enable combined transmit and receive beamforming through signal processing on the received signals. Because of the combined role of transmit and receive arrays in this processing for monostatic MIMO radar, mutual coupling present in these arrays impacts the beamforming in a unique way. This paper therefore presents a mathematical model of a MIMO radar with coupled antennas and appropriate radio frequency circuitry. Application of the model to evaluate radar detection of a single target demonstrates that coupling can result in target detection angles that are in error by as much as 12? and increase beamformer response side lobe levels by as much as 8 dB. The results also show that a simple matching network can improve detection performance, particularly when array mutual coupling is high.
关键词： Radar antennas,Beam steering,MIMO systems,Mutual coupling
更新于2025-09-04 15:30:14
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High energy shift in the optical conductivity spectrum of the bilayer graphene
摘要： We calculate theoretically the optical conductivity in the bilayer graphene by considering Kubo-Green-Matsubara formalism. Different regimes of the interlayer coupling parameter have been considered in the paper. We show that the excitonic effects substantially affect the optical conductivity spectrum at the high-frequency regime when considering the full interaction bandwidth, leading to a total suppression of the usual Drude intraband optical transition channels and by creating a new type of optical gap. We discuss the role of the interlayer coupling parameter and the Fermi level on the conductivity spectrum, going far beyond the usual tight-binding approximation scheme for the extrinsic bilayer graphene.
关键词： interlayer coupling,excitonic effects,Kubo-Green-Matsubara formalism,bilayer graphene,optical conductivity
更新于2025-09-04 15:30:14
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Achieving enhanced pH sensitivity using capacitive coupling in extended gate FET sensors with various high-K sensing films
摘要： Sensing properties of various high-k sensing membrane, such as SnO2, HfO2, ZrO2, and Ta2O5, in dual gate extended-gate field-effect transistor (EGFET) were investigated. By adapting the dual-gate structure, high sensitivity exceeding the conventional Nernstian limit on sensitivity (59.15 mV/pH at 25 °C) was realized due to capacitive coupling effect. As a results, it was confirmed that dual-gate EGFET with Ta2O5 sensing membrane which has high permittivity shows the highest sensitivity of 478.0 mV/pH as well as excellent hysteresis voltage and drift rate characteristics.
关键词： Glass EG detector,Dual gate poly-Si TFT transducer,High-k membrane,Highest sensitivity,Capacitive coupling,EGFET pH sensor
更新于2025-09-04 15:30:14
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An advanced technique of fabricating multi silica directional fiber coupler
摘要： We have investigated the optimum parameter to fabricate multi fiber of silica material for directional coupler based on fusion and elongation techniques. Coupling coefficient between the fibers was derived by using Hankel and Bessel function. However, the fusion temperature was experimentally determined as function of elongation speed. Good performance of multi fiber coupler has been obtained for fabrication parameters of fusion temperature and elongation speed of 1350 oC and 125 μm/s respectively. The proposed coupling coefficient shows a better accuracy with empirical one for various coupling length. It is exponentially increased by reducing the distance between fibers. Finally, the microscopic analysis of coupling region deformation has shown that the silica material was well dispersed and distributed.
关键词： Multi silica fiber coupler,coupling coefficient,fusion and elongation techniques
更新于2025-09-04 15:30:14
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Photodetection probability in quantum systems with arbitrarily strong light-matter interaction
摘要： Cavity-QED systems have recently reached a regime where the light-matter interaction strength amounts to a non-negligible fraction of the resonance frequencies of the bare subsystems. In this regime, it is known that the usual normal-order correlation functions for the cavity-photon operators fail to describe both the rate and the statistics of emitted photons. Following Glauber’s original approach, we derive a simple and general quantum theory of photodetection, valid for arbitrary light-matter interaction strengths. Our derivation uses Fermi’s golden rule, together with an expansion of system operators in the eigenbasis of the interacting light-matter system, to arrive at the correct photodetection probabilities. We consider both narrow- and wide-band photodetectors. Our description is also valid for point-like detectors placed inside the optical cavity. As an application, we propose a gedanken experiment confirming the virtual nature of the bare excitations that enrich the ground state of the quantum Rabi model.
关键词： Cavity-QED,light-matter interaction,ultrastrong coupling,quantum Rabi model,photodetection
更新于2025-09-04 15:30:14
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Improving Interferometry Instrumentation by Mixing Stereoscopy for 2π Ambiguity Solving
摘要： Phase measurements obtained by high-coherence interferometry are restricted by the 2π ambiguity to height differences smaller than λ/2. A further restriction considers linear and nonlinear aberrations evolving in most interferometric systems due to the CCD-type array detectors. The authors present a new method to overcome the 2π ambiguity in interferometry when using a stereoscopic approach. In this method, a reconstructed wavefront reflected from an object was propagated into two different angles to obtain two different images of the object. These two different images were subsequently processed by stereo algorithms to resolve the 2π ambiguity. Such a method of wavefront propagation may enable several applications such as focusing and resolving the 2π ambiguity, as described in the article.
关键词： Wavefront Propagation,Stereoscopy,2π Ambiguity,Coupling Techniques,Interferometric Measurements
更新于2025-09-04 15:30:14