A compact dual band-notched Ultra-Wideband antenna with sharp band-notched characteristics and controllable notched bandwidths is presented. The antenna consists of a spade-shaped microstrip-fed Ultra-Wideband planar monopole antenna and two sets of band-notched structures. The band-notched structures are employed to generate the desired lower and upper rejection bands with good frequency selec...

We report self-consistent Brownian dynamics simulations of a simple electrostatic model of the selectivity filters (SF) of calcium ion channels. They reveal regular structure in the conductance and selectivity as functions of the fixed negative charge Qf at the SF. With increasing Qf, there are distinct regions of high conductance (conduction bands) M0, M1, M2 separated by regions of almost zer...

We report an experimental study of porous silicon-based rugate filters. Possible optimisations that can improve different features of the filters are investigated. We demonstrate sidelobe attenuation by means of half-apodization of the structures with a sinusoidal window. Reduction of interference ripples are experimentally observed through the insertion of index-matching layers on the boundari...

The transverse instability in a beam and the blow-up in its size caused by an electron cloud become increasingly important in high-intensity accelerators. The electron cloud builds up through beam-induced multipacting. We investigated the energy spectrum of an electron cloud with short bunch using particle simulation. A "stop-band" structure is found and a model is suggested to explain and to d...

A wedge-shaped structure made of split-ring resonators (SRR) and wires is numerically simulated to evaluate its refraction behavior. Four frequency bands, namely, the stop band, left-handed band, ultralow-index band, and positive-index band, are distinguished according to the refracted field distributions. Negative phase velocity inside the wedge is demonstrated in the left-handed band and the ...

The past decade has witnessed intensive research efforts related to the design and fabrication of photonic crystals. These periodically structured dielectric materials can represent the optical analogue of semiconductor crystals, and provide a novel platform for the realization of integrated photonics. Despite intensive efforts, inexpensive fabrication techniques for large-scale three-dimension...

The design and performance of a band pass filter for UWB communications is presented in this paper. Open loop resonators consisting of parallel arms (stubs) protruding from a 50Ω transmission line create the required rejection bands. The arms height, width and spacing control the bandwidth achieved by the filter. Each pair of arm creates one reject band in the transmission response. Three filte...

The paper presents a greedy search method based on binary successive approximation-evolutionary search (BSA-ES) strategy to design stable infinite impulse response (IIR) digital filter using L1 optimality criterion. The stability constraints are well taken care of during the design procedure. The filter designed based on L1-approximation error possesses flat pass-bands and stop-bands to that of...