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Stopband

About: Stopband is a research topic. Over the lifetime, 6710 publications have been published within this topic receiving 82087 citations.


Papers
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Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this paper, a composite microstrip bandpass filter (BPF) with a 3 dB fractional bandwidth of more than 100% was designed for ultra wideband (UWB) wireless communications.
Abstract: A new technique is developed for designing a composite microstrip bandpass filter (BPF) with a 3 dB fractional bandwidth of more than 100%. The BPF is suitable for ultra-wideband (UWB) wireless communications. The design utilizes embedding individually designed highpass structures and lowpass filters (LPF) into each other, followed by an optimization for tuning in-band performance. The stepped-impedance LPF is employed to attenuate the upper stopband and quarter-wave short-circuited stubs are used to realize the lower stopband. Two such BPFs are fabricated and measured to demonstrate the performance.

311 citations

Journal ArticleDOI
TL;DR: In this article, a single-layer subwavelength periodic waveguide films with binary profiles are applied to design numerous passive guided-mode resonance elements and it is shown that the profile's Fourier harmonic content, along with the absolute value of the grating modulation strength, affects the resonance linewidth and their relative locations.
Abstract: Single-layer subwavelength periodic waveguide films with binary profiles are applied to design numerous passive guided-mode resonance elements. It is shown that the grating profile critically influences the spectral characteristics of such devices. In particular, the symmetry of the profile controls the resonance spectral density. Symmetric profiles generate a single resonance on either side of the second stopband whereas two resonances arise, one on each side of the band, for asymmetric structures. Moreover, the profile's Fourier harmonic content, along with the absolute value of the grating modulation strength, affects the resonance linewidths and their relative locations. Computed Brillouin diagrams are presented to illustrate many key properties of the resonant leaky-mode spectra in relation to modulation strength and profile symmetry at the second stopband. Associated mode plots elucidate the spatial distribution of the leaky-mode field amplitude at resonance and show that, for small modulation, the mode shape may be simple whereas at higher modulation, the shape appears as a complex mixture of modes. By computing device spectra as function of the modulation strength, the buildup of the final spectral properties is illustrated and the contributions of the various leaky modes clarified. The results presented include wavelength and angular spectra for several example devices including narrow linewidth bandpass filters with extended low sidebands for TE and TM polarization, wideband reflectors for TE and TM polarization, polarizer, polarization-independent element, and a wideband antireflector, all with only a single binary layer with one-dimensional periodicity. These results demonstrate new dimensions in optical device design and may provide complementary capability with the field of thin-film optics.

311 citations

Journal ArticleDOI
TL;DR: In this article, the optical stop band of periodic planar arrays of submicron silica spheres and macroporous polymers grown from these silica templates were observed. And the results were compared to the predictions of the scalar wave approximation.
Abstract: We report observations of the optical stop band of periodic planar arrays of submicron silica spheres, and of macroporous polymers grown from these silica templates. The stop-band width and peak attenuation depend on the number of layers and on the dielectric contrast between the spheres and the interstitial regions, both of which are experimentally controlled. The results are compared to the predictions of the scalar wave approximation. This is the first systematic study of the thickness dependence of the stop band in colloidal photonic band gap structures.

302 citations

Journal ArticleDOI
TL;DR: Using electro-optically generated frequency combs, the authors demonstrate radiofrequency photonic filters that can potentially provide simultaneous high stopband attenuation, fast tunability and bandwidth reconfiguration.
Abstract: Using electro-optically generated frequency combs, scientists demonstrate radiofrequency photonic filters that can potentially provide simultaneous high stopband attenuation, fast tunability and bandwidth reconfiguration.

293 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of the geometrical shapes of a defected groundplane structure (DGS) slot on performance of the Hi-Lo microstrip low-pass filter (LPF) was examined.
Abstract: This paper examines the effect of the geometrical shapes of a defected ground-plane structure (DGS) slot on performance of the Hi-Lo microstrip low-pass filter (LPF). A three-pole LPF based on an arrowhead DGS slot has 67% less length as compared to a conventional three-pole LPF. It has insertion loss of 0.5 dB and 15-dB rejection in the stopband up to three times the cutoff frequency.

292 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023171
2022403
2021282
2020376
2019436
2018420