We present new designs of waveguide components in photonic crystal structures used for routing light exhibiting high transmission. In particular, we focus on the design of a brick that will form the PhCs network, i.e., a double bends and Y-shaped splitter. Photonic crystals are considered a good way for realizing compact optical bends and splitters. The PhC consists of a triangular array of holes etched into InP/GaInAsP/InP heterostructure. Propagation characteristics of the proposed devices are analyzed utilizing two-dimensional finite difference time domain (FDTD) method. The FDTD simulations confirm their unprecedented efficiency and robustness with respect to wavelength and structural perturbations. The PhCs transmission properties are then presented and discussed. Numerical results show that a total transmission of about 75% at output ports is obtained.

In this paper, on the basis of proposing a novel complementary split-ring resonator (CSRR) using Koch fractal curve, a bandpass filter based on such a new structure is designed To validate the designing method. Transmission characteristics and reflection characteristics of the presented filter are given by both software simulation and experiment measurement. Consistent results have confirmed the design concept and excellent performance of the new structure and indicated that the proposed filter has a low insertion loss a high selectivity and small size.

This paper introduces a new design technique for a capacitive gap-coupled bandpass filter (BPF) using non-uniform arbitrary image impedances. Based on the proposed BPF equivalent circuit model, the filter's design equations are derived, and they are validated from comparisons of the calculated and simulated results. For this theoretical verification, the BPF using non-uniform arbitrary image impedances is designed using the specifications of: center frequency (f_c)=5.8 GHz, fractional bandwidth (FBW)=3.5%, and filter stage (N)=3. The calculated and simulated results of the designed filter show good agreement. The BPF using the proposed design method could provide an advantage that one can arbitrarily determine two different image impedances, which ultimately affects the BPF's coupling gaps and line widths. This could result in suitable filter dimensions, i.e., gaps and line width, for a conventional low resolution photolithography fabrication although a low or high dielectric constant substrate is used for the design.

Ultra wideband components have been developed using SIW technology. The various newly developed components include a GCPW transition, Y and T-junctions. The GCPW transition covers over 10 GHz bandwidth with less than 0.4 dB insertion loss. The optimized T and Y-junctions have relatively wide bandwidths of greater than 40% that have less than 0.6\,dB insertion loss. The developed transition was utilized to design an X-band eight-way power divider that demonstrated excellent performance over a 4 GHz bandwidth with less than ±4º and ±0.9 dB phase and amplitude imbalance, respectively. Theoretical and experimental results are presented and compared with previously designed SIW power dividers. The developed SIW power divider has a low profile and is particularly suitable for circuits' integration.

A novel coplanar waveguide (CPW)-fed circularly polarized (CP) antenna is proposed. The antenna is composed of a square ground plane with a circular slot and an equiangular tapered-shaped feedline. With the use of a special shaped feedline, the axial ratio (AR) bandwidth of the proposed antenna is about 61.9% (2.9-5.5 GHz), which is larger than most of similar antennas proposed before. In addition, the impedance bandwidth, determined by 10-dB return loss, is between 2.9-20 GHz, which makes the antenna be used for ultra-wideband (UWB) applications.

In this paper, a calibration technique for the position sensor via support vector regression (SVR) is proposed. The position sensor adopts a zero-intermediate frequency architecture based on a six-port network, which is used for directly measuring the phase differences and indirectly reflecting the position. The SVR, which implements the structural risk minimization (SRM) principle, provides a good generalization ability from size-limited data sets. The results indicate that the SVR model can achieve a great predictive ability in positioning, with an accuracy of 2.41 mm over a distance range of 274.5 mm.

A printed monopole ultra wideband (UWB) antenna with frequency band-notched characteristics is proposed and investigated. The antenna consists of a half-disk shaped structure combined with an inverted isosceles trapezoid structure. To achieve the frequency band notched characteristics, an open-ended thin slit with a length of about one quarter guided wavelength is inserted on the radiator. Multiple slits can be employed to realize multiple frequency band notched characteristics. To validate the concept, two prototypes are designed, fabricated and tested. The first is a single band notched UWB antenna whereas the second is a dual band notched UWB antenna. The simulated and measured results of both antennas are presented shown a reasonable agreement between them. The results also confirm the proposed UWB antenna design can achieve superior dual band-notch performance at desired frequency bands.

The design and analysis of a high-power wideband sheet-beam coupled-cavity traveling-wave tube operating at V-band is presented. The interaction circuit employs three-slot doubly periodic staggered-ladder coupled-cavity slow-wave structure, and a 5 : 1 aspect-ratio sheet electron beam is used to interact with the circuit. Combined with design of the well-matched input and output couplers, a 3-D particle-in-cell model of the sheet-beam coupled-cavity traveling-wave tube is constructed. The electromagnetic characteristics and the beam-wave interaction of the tube are investigated. From our calculations, this tube can produce saturated output power over 630 Watts ranging from 58 GHz to 64 GHz when the cathode voltage and beam current are set to 13.2 kV and 300 mA, respectively. The corresponding saturated gain and electron efficiency can reach over 32.5 dB and 15.9%. Compared with the circular beam devices, the designed sheet-beam TWT has absolute advantage in power capability, and also it is more competitive in bandwidth and electron efficiency.

In this letter, a novel compact quad-band microstrip circular slot antenna using edge-feeding is proposed to support the four wireless communication bands of GPS1.575 (1.525-1.625 GHz), WIMAX3.5 (3.3-3.6 GHz), WLAN2.45 (2.4-2.485 MHz)and WLAN5.2/5.8 (5.15-5.825 GHz). To expand the bandwidth of the GPS band and induce the WIMAX/WLAN band to support quad-band applications without affecting the compactness of the proposed antenna, a good method of implanting two T copper slices at the inner boundary of the two circular slots respectively is adopted. By adjusting the diameter of the two circular slots and the size of the T-shaped patch, resonant frequencies and bandwidth of the antenna are controlled and the multiple operating bands are achieved. In order to further reduce the size of the antenna that an edge-fed technology is used. This antenna has a simpler structure for realizing quad-band characteristics. Then, a prototype of the proposed antenna was successfully implemented, and good radiation performance is observed in all desired bands.

We investigate experimentally the collisions of nonlinear envelope pulses in a left-handed transmission line with regularly spaced Schottky varactors. By measuring the test line, we successfully observed that when two nonlinear envelope pulses traveling in opposite directions collide, two new envelope pulses are developed. These new pulses satisfy the phase-matching condition, and their carrier wave frequencies are the sum of the carrier wave frequencies of the original pulses. This article describes the experimental observations, together with the fundamental properties and numerical performance prospects of the test line.

The effect of exponentially graded material on the modal dispersion characteristics, group velocity and effective group index as well as phase index of refraction of a binary One-Dimensional Plasma Photonic Crystals (1D-PPCs) has been studied. The dispersion relation is derived by solving Maxwell's equations and using the transfer matrix method. The anomalous dispersion characteristics are observed for different values of selection parameters. The introduction of graded dielectric layers in 1D-PPCs provides additional parameters for controlling the propagation characteristics of 1D-PPCs. Also, the band gap is shown to become larger with the increase of plasma frequency and plasma width. Hence the structure having plasma and exponentially graded dielectric layer in unit cell is more useful for controlling and tuning of the plasma functioning devices than the structure having plasma and homogeneous dielectric layer in one unit cell.

A generalized equivalent cable bundle method (GECBM) is presented for modeling electromagnetic (EM) compatibility issues of complex cable bundle terminated in arbitrary loads. By introducing a new grouping criterion, complex cable bundles terminated in arbitrary loads can be reasonably simplified through a generalized equivalence procedure. The reduced cable bundle model can be used for modeling electromagnetic immunity, emission and crosstalk problems. The complexity and the computation time for the complete cable bundle modeling has been significantly reduced and fairly good precision is maintained. Numerical simulations are given to validate the efficiency and advantages of the method.

The scattering properties of dielectric waveguides connected in cascade can be obtained by using the generalized scattering matrix concept, together with the generalized telegraphist equations formulism and the modal matching technique. This review aims to show the potential of periodic structures in dielectric waveguides in order to gain control of light in the design of microwave and photonic devices. The new inverted Π dielectric waveguide is presented. Numerical and experimental results of the complex scattering coefficients were obtained at microwave frequencies. At optical frequencies, results for planar waveguide photonic crystals are included and compared with the numerical values from commercial software. In all cases the agreement was excellent. Electromagnetic and photonic band gaps, photonic windows, optical switching, optical resonant microcavities as well as refractive index optical sensors can be achieved by means of dielectric waveguides in cascade.

The development of a compact metal mountable Radio-Frequency IDentification (RFID) tag antenna on a ceramic substrate based on Barium Titanate is presented. The performance limitations and design trade-offs of metal mountable RFID tag antennas are reviewed and the favorable features of a high-permittivity antenna substrate for the development of antennas for metal mountable RFID tags are discussed. The simulation-based tag antenna design process is outlined and the measured read range of the developed metal mountable tag on conductive platforms of various sizes is presented.

Design of high performance package interconnects using full-wave electromagnetic solvers is necessary due to increased operation speed, miniaturization and vertical 3D integration. Thus the segmented study and optimization is becoming inevitable for designers to improve the signal integrity of IC packaging. This paper addresses alternative methods and optimal designs on several components and structures for package electrical interconnects, including voiding technique, padless via implementation, spiral micro-via stacking and signal/ground layout pin patterns. The simulation results have been presented to demonstrate the improvements of optimized schemes. These methodologies could be treated as handy references and general guidelines applicable to different package designs and could result in significant improvements of overall package signal integrity performance.

This paper presents a design methodology for realizing broadside-coupled microstrip bandpass filters on multilayer substrates to reduce the size of the filter. The new filter configuration consists of broadside coupled split-ring resonators on two layers backed by a ground plane. With the proposed new method, miniaturization to a greater extent can be achieved compared to the conventional method of realizing microstrip multilayer filters. In addition, coupling apertures in the ground plane used to achieve coupling among the resonators in conventional multilayer structures are eliminated. The proposed design is more flexible compared to traditional multilayer filters. Layers can be easily added to increase the filter order. To demonstrate the method, a miniaturized two-layered bandpass filter centered at 728 MHz with low insertion loss is implemented and investigated. Miniaturization of more than 25% is achieved compared to the conventional broadside coupled structure and more than 40% miniaturization compared to the edge coupled structure. The new microstrip filter discussed in this paper can be realized using simple fabrication techniques.

In this paper, an approach for the synthesis of Ultra-Wideband (UWB) antenna systems in the time domain is proposed. Starting from the definition of suitable time-domain performance indexes, the design process is based on a spline representation of the antenna shape and a Particle Swarm Optimization (PSO) aimed at matching optimal radiation and electrical conditions. The effectiveness of the proposed time-domain technique is assessed by means of both numerical and experimental results.

Spectrum sharing analysis is remarkably important in investigating the possibility for coexistence between IMT-Advanced system and existing wireless services when operating in the same or adjacent frequency channel. The frequency band, 470-862 MHz, is currently allocating to TV broadcasting services (TVBS) and sub-bands within it are also allocated to fixed wireless access (FWA) service. Recently, international telecommunication union-radio (ITU-R) sector has allocated sub-bands within 470-862 MHz for IMT-Advanced systems. This concurrent operation causes destructive interference that influences the coexisting feasibility between IMT-Advanced and these existing services, FWA and broadcasting. This paper addresses a timely and topical problem dealing with spectrum sharing and coexistence between IMT-Advanced systems and both FWA and TVBS within 790-862 MHz. Co-channel and adjacent channel with an overlapping band and with or without guard band are intersystem interference scenarios investigated. The deterministic analysis is carried out by spectral emission mask (SEM) technique as well as interference to noise ratio graph. Various significant factors such as channel width, propagation path lengths, environments losses, and additional losses due to antenna discrimination which influence the feasibility of coexistence are evaluated. Feasible coexistence coordination procedures in terms of carrier frequency offset, separation distance, coverage cell size and required additional isolation are suggested.

This paper presents the design of two suspended substrate stripline (SSS) bandpass filters (BPFs), both with a source-load coupling structure embedded to create a transmission zero (TZ) near each side of the passband edges. For the first BPF, the physical circuit layout is proposed first and followed by the establishment of an equivalent LC circuit. The optimization of element values of the LC circuit using a circuit-level simulator leads to quick adjustment of the structural parameters of the physical circuit layout with the aid of a full-wave simulator. For the second BPF, the ingenious equivalent LC circuit modified from that of the first one is proposed for bandwidth enhancement, which is achieved by exciting two extra loaded resonances in the passband. With the element values of the LC circuit optimized, proper reshaping the physical circuit layout from that of the first BPF is easily accomplished. The presented lumped and full-wave mixed approach is very efficient in that the circuit-level simulator is used to the largest extent and the time-consuming full-wave simulator is employed only at the later stage of the design. Experiments are conducted to verify the design of the two SSS BPFs and agreements are observed between the measured and simulated data.

The accuracy of the finite difference frequency domain (FDFD) method in the solution of canonical waveguide discontinuity problems involving complementary or nearly complementary metamaterials (MTMs) is analytically discussed. It is shown that the good accuracy of the method (in comparison with other frequency-domain techniques) is due to the intrinsic approximation which it introduces in the finite-difference discretization of sharp dielectric interfaces. By exploiting such a result, a perturbation algorithm is proposed for the reliable modeling of MTMs devices when other frequency domain numerical methods are at disposal. A preliminary numerical analysis is carried out to assess the reliability and accuracy of the proposed modeling approach when canonical scattering problems are at hand.