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Bandwidth (signal processing)

About: Bandwidth (signal processing) is a research topic. Over the lifetime, 48550 publications have been published within this topic receiving 600741 citations. The topic is also known as: Bandwidth (signal processing) & bandwidth.


Papers
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Journal ArticleDOI
TL;DR: In this article, a reconfigurable wideband and multiband C-slot patch antenna with dual-patch elements is proposed and studied, where two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and wideband modes.
Abstract: A reconfigurable wideband and multiband C-Slot patch antenna with dual-patch elements is proposed and studied. It occupies a compact volume of 50 × 50 × 1.57 (3925 mm3), including the ground plane. The antenna can operate in two dual-band modes and a wideband mode from 5 to 7 GHz. Two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and the wideband modes. Two switches, implemented using PIN diodes, are placed on the connecting lines of a simple feed network to the patch elements. Dual-band modes are achieved by switching “ON” either one of the two patch elements, while the wideband mode with an impedance bandwidth of 33.52% is obtained by switching “ON” both patch elements. The frequencies in the dual-band modes can be independently controlled using positions and dimensions of the C-Slots without affecting the wideband mode. The advantage of the proposed antenna is that two dual-band operations and one wideband operation can be achieved using the same dimensions. This overcomes the need for increasing the surface area normally incurred when designing wideband patch antennas. Simulation results are validated experimentally through prototypes. The measured radiation patterns and peak gains show stable responses and are in good agreements. Coupling between the two patch elements plays a major role for achieving the wide bandwidth and the effects of mutual coupling between the patch elements are also studied.

172 citations

Journal ArticleDOI
27 Oct 2014
TL;DR: A time-interleaved (TI) SAR ADC which enables background timing skew calibration without a separate timing reference channel and enhances the conversion speed of each SAR channel and incorporates a flash ADC operating at the full sampling rate of the TI ADC.
Abstract: SARs are one of the most energy-efficient ADC architectures for medium resolution and low-to-medium speed. To improve the limited bandwidth of SAR ADCs, the time-interleaved (TI) structure is often used [1,2]. However, TI ADCs have several issues caused by mismatches between channels, such as offset, gain, and timing-skew errors. Unlike the other errors, timing-skew causes errors that increase with input signal frequency. Considering that the TI structure is typically employed to increase bandwidth, timing-skew can be a dominant error source of TI ADCs. Recent works [1,3] have demonstrated a background timing-skew calibration using a dedicated additional channel as a timing reference. In this work, we present a TI SAR ADC that enables background timing-skew calibration without a separate timing reference channel and enhances the conversion speed of each channel.

171 citations

Journal ArticleDOI
TL;DR: The conclusion from investigations into these two approaches is that for general beamforming applications, the guided-wave approach is superior, achieving good bandwidth, scanning range, insertion loss, and small structure thickness, with only moderate fabrication complexity.
Abstract: Recent advances in wireless sensing and communications have resulted in the need for antennas capable of high-directivity reconfigurable beamforming. Transmitarrays have been shown to be viable architectures, and two general design approaches have emerged: the layered-scatterer approach and the guided-wave approach. In this paper, we first investigate the beamforming capability of the layered-scatterer approach, generalizing the approach using impedance surfaces. Using Floquet mode analysis, we show that when a structure of this type is used to produce a pencil beam at angles greater than 20 degrees off-broadside, significant side-lobes are produced at large angles, regardless of the aperture size. Next, we present a fully reconfigurable 6 × 6 transmitarray based on a guided-wave approach that experimentally demonstrates both pencil beam scanning over a 100 × 100-degree window as well as shaped-beam synthesis, over a 10 percent fractional bandwidth. The conclusion from our investigations into these two approaches is that for general beamforming applications, the guided-wave approach is superior, achieving good bandwidth, scanning range, insertion loss, and small structure thickness, with only moderate fabrication complexity.

171 citations

Journal ArticleDOI
R.A. Linke1, Alan H. Gnauck1
TL;DR: The most significant obstacles to the attainment of quantum-noise limited detection at higher speeds are seen to be the requirement of uniform frequency response from electronic components and the local oscillator laser power requirement, which increases as the square of the bit rate.
Abstract: Recent theoretical work on coherent optical detection systems is reviewed and experimental results in high-speed coherent transmission are summarized. The theoretical advantages and limitations of the various modulation and detection formats are discussed and experimental progress towards the implementation of these systems is reviewed. The most significant obstacles to the attainment of quantum-noise limited detection at higher speeds are seen to be the requirement of uniform frequency response from electronic components and the local oscillator laser power requirement, which increases as the square of the bit rate. To make full use of the single-mode fiber bandwidth, frequency-division multiplexing of many moderate-rate channels is a very promising technique for local systems. For long-distance applications, frequency multiplexing is still possible but is limited by the need for optical amplifiers or wavelength-selective multiplexers. >

171 citations

Proceedings ArticleDOI
23 Aug 2018
TL;DR: This paper summarizes wireless communication research and activities above 100 GHz, overviews the results of previously published propagation measurements at D-band (110–170 GHz), provides the design of a 140 GHz wideband channel sounder system, and proposes indoor wideband propagation measurements and penetration measurements for common materials at 140 GHz which were not previously investigated.
Abstract: With the relatively recent realization that millimeter wave frequencies are viable for mobile communications, extensive measurements and research have been conducted on frequencies from 0.5 to 100 GHz, and several global wireless standard bodies have proposed channel models for frequencies below 100 GHz. Presently, little is known about the radio channel above 100 GHz where there are much wider unused bandwidth slots available. This paper summarizes wireless communication research and activities above 100 GHz, overviews the results of previously published propagation measurements at D-band (110–170 GHz), provides the design of a 140 GHz wideband channel sounder system, and proposes indoor wideband propagation measurements and penetration measurements for common materials at 140 GHz which were not previously investigated.

171 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202217
20211,517
20202,656
20193,121
20183,100
20172,744