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.

The design process of a double-sided slotted TORUS axial-flux permanent-magnet (AFPM) motor suitable for direct drive of electric vehicle (EV) is presented. It used sizing equation and Finite Element Analysis (FEA). AFPM motor is a high-torque-density motor easily mounted compactly onto a vehicle wheel, fitting the wheel rim perfectly. A preliminary design is a double-sided slotted AFPM motor with 6 rotor poles for high torque-density and stable rotation. In determining the design requirements, a simple vehicle-dynamics model that evaluates vehicle performance through the typical cruising trip of an automobile was considered. To obtain, with the highest possible torque, the initial design parameters of the motor, AFPM's fundamental theory and sizing equation were applied. Vector Field Opera-3D 14.0 commercial software ran the FEA of the motor design, evaluating and enhancing accuracy of the design parameters. Results of the FEA simulation were compared with those obtained from the sizing equation; at no-load condition, the flux density at every part of the motor agreed. The motor's design meets all the requirements and limits of EV, and fits the shape and size of a classical-vehicle wheel rim. The design process is comprehensive and can be used for an arbitrary EV with an arbitrary cruising scenario.

Noise reduction in PCB is a major concern in the present digital electronic systems with data rate beyond 10 Gbps. The noise, due to simultaneous switching noise, radiation from signal vias crossing the planes, etc. can propagate within parallel plane cavity at its resonant frequencies, thus allowing coupling between integrated circuits (ICs) far from each other. Electromagnetic band-gap (EBG) structures are largely employed as noise reduction technique. This paper presents a quick and efficient analytical approach for evaluating the EBG noise reduction performances in terms of band-gap limits. The study is based on the physics behavior of the planar EBG structures, focusing on its resonant properties. The resonant modes of the EBG cavity are affected by the additional inductance of the patterned plane respect to the case of the ideal solid plane cavity. The formulas provided, based on the quantification of such inductance, can be easily implemented and employed for a quick layout design of power planes in multilayer PCBs, as shown in a practical example of a partial EBG plane.

We simulate a 1D ternary photonic crystal (TPC) employed as a clad of a photonic crystal waveguide (PCW) which consists three different lossless dielectric layers as a unit-cell. Calculating input impedance at each layer interface and using a lossless reciprocal transmission line as a model, we can predict angle intervals in which reflection occurs due to photonic crystal effect. Comparing this method with transfer matrix method and bang structure shows perfect agreement.

A new microstrip structure for realization of wideband phase shifter has been designed and fabricated. The proposed design uses edge-coupled semi-elliptical structure and an elliptical defected ground plane to increase the coupling coefficient and operating bandwidth. Simulation performed using CST Microwave Studio and measured results confirm the good performance of the proposed design. The phase deviation is better than ±4º, insertion loss less than 0.6dB and return loss better than 10dB over a wide frequency range. The achievable bandwidth is more than 2.3 : 1.

A new design of a circularly polarized single-layer antenna which has a compact structure of 10mm×20mm×1mm is presented. The proposed antenna only consists of a feedline and a rectangular ground plane both printed on the same metallic layer. To compact the antenna size and overcome the high impedance problem, the circular polarization (CP) operation can be attained by locating the feedline at the left of the ground plane. Parameters such as substrate length and patch length are investigated and design results from parametric simulations are presented.

A tunable impedance matching network is applied to achieve very widely tunable antennas, whose geometries are independent and unchanged to simplify the design. The attached matching network as the antenna feeding network enables any unspecified UWB antenna to tune the operation frequency continuously with high selectivity by merely one single control. This is quite different from filter-based concept which is complicated to co-design and implement a tiny narrow band tunable filter over wide frequency ranges and very difficult to control with one element. And also the design, adjustment, and optimization of the matching network are much simpler, quicker, and lower cost than geometry-modified antenna design. The analysis of precise high frequency circuit models is used predict the performance in simulation. Fabricated prototype antennas are measured by using horn antennas to validate the antenna performance. The tunable frequency ranges from 1.8 GHz to 2.8 GHz (155%) and 2.19 GHz to 3.86 GHz (176%). Moreover, compared to other matching network-based solutions, non-ideal effects in undesired bands other than the operation frequency band are suppressed, so the performance is improved. One wide-tuning antenna using one single element to control can be carried out by tunable matching networks without complicated designs.

This paper proposes a compact ultrawideband monopole antenna fed by CPW with a 5.5 GHz notched band of WLAN/WiMAX systems. The antenna input section is designed by using a gradual curvature central line and ground planes for ultrawideband achievement. In order to reject the unwanted frequency of the existing WLAN/WiMAX band, the C-shaped slit with perimeter length of a half wavelength at center frequency of 5.5 GHz has been embedded into the monopole patch. The designed antenna is completely implemented and measured for impedance bandwidth covering UWB range and stably performs omnidirectional pattern in $xz$ plane from 3.1 to 10 GHz. The proposed antenna could potentially minimize frequency interference in the WLAN/WiMAX bands.

A high-performance multilayer dual-mode filter is developed based on the substrate integrated waveguide circular cavity (SICC) in this paper. The filter is constructed with two circular cavities and each cavity supports two degeneration modes, which can be generated and controlled by the coupling aperture and slot located between layers. Detailed design process is introduced to synthesize an X-band dual-mode dual-layer filter. It not only has the good performances, but also reduces the circuit size much more. Moreover, it can be found that the upper side response of the filter is very steep. Good agreement is obtained between the simulated and measured results of the proposed structure.

In this paper, electromagnetic optimal design is carried out for dual-band radome wall with alternating layers of staggered composite and Kagome lattice structure. The novel wall structure provides broadband transmission capability, along with excellent thermal-elastic properties and mechanical performances for high temperature applications. By optimizing the layer number (n) and the thickness of the whole wall (d), the power transmission efficiency of the novel structure in the frequency range of 1-100 GHz is calculated via boundary value method (BVM) based on electromagnetic theory. The calculation results suggest that if the wall thickness is dimensioned to be 6 mm and the wall structure is designed as 5 layers, the novel structure demonstrates excellent transmission performance. The optimal design results show that the power transmission efficiency is higher than 80% from 1 to 31 GHz in the centimeter wave range and from 59 to 100 GHz in the millimeter wave range, and the average transmission efficiency over the pass band reaches as high as 91%.