In this paper, a compact metamaterial quad-band antenna is presented. The antenna is designed from a unit cell of asymmetric extended-composite right/left handed transmission line (E-CRLH TL) as the main resonator part and a 50 Ω coplanar waveguide (CPW) as the feeding part. The design concept and resonant frequencies are analyzed and discussed. The results show that the proposed antenna exhibits four frequency bands covering GSM810, WLAN 2.45/5.5 GHz and WiMAX 3.5 GHz bands. The overall size of the fabricated antenna is only 57.2 mm×31.2 mm×1.6 mm and is very small compared with other proposed quad-band antennas. In addition, a good agreement can be seen among the estimated resonant frequencies, HFSS simulated and measured results.

A dual-frequency InSAR imaging technique is proposed to estimate the position and motion parameters of a moving target, including velocity and cross-track acceleration. By applying a dual-frequency technique, phase ambiguity is effectively removed to obtain accurate estimation of motion parameters.

An alternative formulation of the Small Perturbation Method (SPM) in solving electromagnetic scattering from multi-layer random rough surfaces to resolve singularities in spectral integrals is presented. Non-monotonic permittivity changes will allow a multi-layer structure with flat interfaces to support guided modes. The presence of these guided modes translates to poles in the zeroth order Green's function of the media for the surface fields. The poles appear in the first and second order perturbation solutions based on a iterative procedure. Thus, evaluating the spectral integrals to obtain the spatial fields becomes problematic. The Sommerfeld integration path instead of real line integrals is introduced by analytic continuation of the integrand into complex spectral space. It is verified that this alternative spectral integration method is valid for both monotonic and non-monotonic cases.

To improve stability of time-domain integral equation, a stable implicit scheme is proposed to solve the transverse-magnetic (TM) electromagnetic scattering from 2D conducting objects. The time-domain electric-field integral equation (TD-EFIE) was adopted and expressed using second-order derivative of the magnetic vector potential. To reduce numerical error, the magnetic vector potential was approximated by second-order central finite difference. TM transient scattering from 2D conducting objects was calculated by an implicit marching-on-in-time (MOT) scheme. To obtain stable numerical results, the TD-EFIE MOT implicit scheme was firstly combined with the time-averaging technique. The accuracy and stability of the scheme were demonstrated by comparison with the results from inverse discrete Fourier transform technique.

A Frequency Selective Surface (FSS) reflector with wideband response for 4G/X-band/Ku-band is proposed. The wideband FSS reflector consists of cascaded dual-layer patch FSS which is etched on separate layers of FR4 substrate. The targeted frequency range is 5-16 GHz. A wide stopband of 10.4 GHz (100% percent bandwidth) is obtained with two layers in cascade. The Equivalent Circuit (EC) method is used to approximate the simulated results. An extensive parametric study is also carried out to understand the effect of various combinations of FSS layers and their disposition. A panel of final FSS is fabricated where measured and simulated results agree well.

A compact ultra-wideband (UWB) top-loaded antenna for multiservice wireless applications is presented. It consists of a metal cone radiator, a small ground plane, four shorting poles and a top-cross plate, among which the top-cross plate with two slots shorted to the ground planet is important to broaden the low frequency bandwidth. The measured result shows that an improved impedance bandwidth of 185% from 1.17 to 30 GHz is achieved. The omnidirectional stable radiation pattern in the horizontal plane is also obtained. The volume of proposed design is approximately 0.0173λ³ at 1.17 GHz. With the small volume and UWB characteristic, the design of the proposed antenna is very suitable for many wireless standards such as Softbank (1427-1500 MHz), DCS1800, PCS1900, UMTS, IMT2000, Wi-Fi (2.4 GHz), WiMAX (2.2-5.5 GHz), UWB (3.1-10.6 GHz), and satellite communication (X band, Ku band and Ka band).

In this paper linear and nonlinear properties of graphene at millimeter wave frequency band are investigated. The nonlinear properties of the graphene are utilized to design frequency multiplier and mixer for millimeter wave applications. A patch of graphene is deposited on the dielectric image guide that will generate higher order harmonics. The amplitude of harmonics is optimized based on the dimensions of the graphene patch on top of the dielectric image guide. A frequency multiplier and mixer are designed, which utilize the second harmonics generated through graphene. The nonlinear behavior of the proposed designs has been simulated in the 50-75 GHz input signal frequency range. A conversion efficiency of -23 dB is obtained for the second harmonic for the frequency doubler. The frequency mixer is designed to mix two frequencies in V-band using dielectric image guide as the waveguide. A -28 dB conversion efficiency is simulated on a dielectric image-guide platform.

In this paper, we present a compact tri-band bandpass filter (BPF) using two stub-loaded dual mode resonators (SLDMRs) combined with intra-coupled internal resonators. The designed filter operates at 1.575, 2.4, and 3.45 GHz, corresponding to the GNSS, WLAN, and WiMAX applications, respectively. The passbands of the filter are determined by odd- and even-mode frequencies created by the SLDMR and the internal open loop resonator inside of it. The corresponding even-mode frequency can be adequately tuned by adjusting the length of the stub while the odd-mode frequency is fixed. Two transmission zeros (TZs) are introduced on each side of the passband to improve the selectivity of the implemented filter. Five TZs around the edges of three passbands make the passbands highly isolated, and these transmission zeros can be placed according to the desired choice. The proposed tri-band BPF was designed, fabricated and measured, and the simulated and measured results corresponded very well.

The uniformity of the incident electromagnetic radiofrequency fields (RF) is an important factor that can influence the results in biological in vivo and/or in vitro exposure experiments using animals and humans or their cells. The International Electrotechnical Commission (IEC) has published IEC 61000-4-20 standard which defined field uniformity criteria for emission and immunity testing in a defined region in transverse electromagnetic (TEM) waveguides. In this paper, we present a numerical analysis method to determine aperture field uniformity in biological experiments according to IEC 61000-4-20:2010 standard. With the numerical analysis method, the uniformity of electromagnetic field can be analyzed in Cartesian coordinates system by aperture-field method (AFM). Then, with the simultaneous application of AFM and the field uniformity criteria defined by IEC 61000-4-20:2010, the two functions can be programmed to evaluate the field uniformity in region of interest (ROI) which can then be meshed into the given observation points where biological examples are exposed to RF. At the specified position of ROI along z far from the aperture of the WR-430 rectangular open-ended waveguide, the field and the minimum uniform distances vs. frequencies can be calculated by AFM. Thus, the results of the numerical analysis method can be applied to design the exposure setups for biological experiments with the field uniformity required in ROI.

In this paper, sequential parametric detection problem is addressed for non-Gaussian correlated clutter. It is well known that the assumption of normally distributed clutter leads, mostly, to analytical expressions of the threshold as well the distribution of detection statistic. Nevertheless, due to the resolution improvement of recent sensing instruments such as high resolution radar, the Gaussian assumption is unrealistic since the clutter is nonhomogeneous. As a consequence, using non-Gaussian assumption of the clutter prevents, mostly, of obtaining analytical expressions of the threshold and the distribution of detection statistics. In this work, we overcome this issue by use of the so called bootstrap techniques for dependent data. Numerical simulations reveal that our proposed method outperforms the classical and sequential non-bootstrap based detection schemes in terms of probability of detection and selects the optimum sample size needed to achieve the required detection performances.

A Compact Non-Bianisotropic Complementary Split Ring Resonator (NB-CSRR) based microstrip triple band antenna is presented in this paper. The antenna has a simple structure compared to other antennas for triple band operation. The antenna consists of a microstrip-fed NBCSRR loaded radiating element and partial ground plane. The designed antenna has a compact size of 29.4 mm x 26 mm x 1.6 mm. Two NBCSRR slots are etched on the radiating patch. Bottom NB-CSRR is used to generate new resonance, and top NB-CSRR is used to improve the return loss. The measured data show that the antenna covers the frequency ranges of 2.5 GHz-3.61 GHz, 4.06 GHz-4.69 GHz, 4.80 GHz-6.07 GHz with impedance bandwidth of (<-10 dB) of 1.11 GHz, 0.63 GHz and 1.27 GHz. The results show that the antenna can cover WLAN and C band applications.

The paper presents an advanced quasi-FEA technique on the iron losses prediction using Bertotti's iron loss separation models, in which a curve fitting is taken into account for coefficients calculation of each model. Moreover, the skin effect and saturation consideration are applied in order to check the accuracy through the relative error distribution in the frequency domain of each model from low up to high frequencies 50 to 700 (Hz). Additionally, this comparative study presents a torque-speed-flux density computation that is discussed and presented. The iron loss characteristics of a radial flux permanent magnet synchronous machine (PMSM) with closed-slots and outer rotor topology are also discussed. The quasi-finite-element (FE) analysis was performed using a 2-D and 3-D FEA, where the employed quasi-2-D FEA is proposed and compared with 3-D FEA, and along with experimental verifications. Finally, all the iron-loss models under realistic and non-ideal magnetization conditions are verified experimentally on a surface-mounted PMSG for wind generation application.

A 3-dB branch-line hybrid coupler with wide stopband responses is presented in this letter. An equivalent K-inverter with bandpass function is used instead of one quarter-wavelength transmission line, which will realize size reduction and wide stopband characteristic of the coupler. Prototype of a branch-line hybrid coupler, which divides the power equally with 90° phase difference between the output ports, is also fabricated and tested. Both the simulation and measurement results show that such a hybrid coupler exhibits an 83.2% size reduction and has transmission suppression of -20 dB or less within five-fold bandwidth.

This article presents the design, simulation and machining of a dual Orthomode Transducer for feeding antenna using waveguide technology. Linear orthogonal polarizations in common port are separated to single linear polarizations in other ports. This device is developed to work in K and Ka bands and could be exploited in satellite communications applications. Also, it is designed to provide good scattering parameters results experienced with simulation tools and real load laboratory measurement. The designed circuit exhibits important results with return losses less than 25 dB, insertion losses in theory of about 0.05 dB as well as a good isolation of 40 dB in both frequency bands of interest (19.4 GHz-21.8 GHz) and (27 GHz-32 GHz).

This paper presents a circularly polarized tag on a 3×3 AMC structure to obtain longer read range for UHF RFID on-body applications. A modified T-matching transformer is employed to achieve conjugate matching with the Monza 4 microchip. To overcome the influence of lossy human body, a cross-dipole tag antenna is directly implemented on the phase-dependent AMC structure to achieve high gain and isolate the influence of the human body. Then, the tag is pasted on a lossy human model to investigate its performance. The study finds that the AMC can increase the antenna gain by 3.34 dB and help generate circularly polarized (CP) wave. The measured fractional bandwidth of impedance is 3.2% which can cover the UHF RFID bands of North America and Taiwan. The measured read range of the tag pasted on a human body reaches 15.7 meters when the reader has 4 W EIRP, and the sensitivity of the microchip is -16.7 dBm.

The efficacy of applying magnetic hyperthermia (MHT) and capacitive hyperthermia (CHT) to treat hepatocellular carcinoma (HCC) is studied. Magnetoquasistatic (MQS) and electroquasistatic (EQS) formulations are develpoed to compute the magnetic field and electric field dirtributions, respectively, which are numerically solved by using finite element method. The heat transport equation is applied to compute the temperature distribution in the treated area. Simulation results of temperature distribution are used to compare the efficacy of MHT and CHT.

The finite element implement of the generalized Lorenz gauged A formulation has been proposed for low-frequency modeling. However, the inverse of mass matrix of intermediate scalar in the finite element implement leads to additional computation cost and dense coefficient matrix. In this paper we propose to adopt a diagonal lumping mass matrix in the finite element discretization of the generalized Lorenz gauged double-curl operator in charge-free electromagnetic problems. Consequently, a sparser discrete system with improved condition number is thus obtained which is more favourable for low-frequency modeling in frequency-domain analysis. Furthermore, we apply the diagonal lumping formulation in time-domain analysis, showing that it can remedy spurious linear growth problem. Numerical examples are used to demonstrate the validity.

In this paper, an efficient Transmission Line Matrix (TLM) algorithm for modeling chiral media is presented. The formulation is based on auxiliary differential equations (ADE) of electric and magnetic current densities. Permittivity and permeability are assumed to follow the Lorentz model while chirality is assumed to follow the Condon model. The proposed method models the dispersive nature of permittivity, permeability, and chirality by adding both voltage and current sources in supplementary stubs to the conventional symmetrical condensed node (SCN) of the TLM method. The electromagnetic coupling appears explicitly in the update equations of the voltage and current sources. The algorithm is developed to simulate electromagnetic wave propagation in a chiral medium. The co-polarized and cross-polarized transmitted and reflected waves from a chiral slab due to a normal incident plane wave are calculated. Validation is performed by comparing the results obtained from the proposed method with those obtained analytically.

A higher-order accurate solution to electromagnetic scattering problems is obtained at reduced computational cost in a p-variable finite volume time domain method in a scattered field formulation. Spatial operators of lower order, including first-order accuracy, are employed locally in substantial parts of the computational domain during the solution process. The use of computationally cheaper and lower order spatial operators does not affect the overall higher-order accuracy of the solution. The order of the spatial operator at a candidate cell during numerical simulation can vary in space and time and is dynamically chosen based on an order of magnitude comparison of scattered and incident fields at the cell centre. Numerical results are presented for electromagnetic scattering from perfectly conducting two-dimensional scatterers subject to transverse magnetic and transverse electric illumination.

A dual-function radar-communication system is a technology equipped with a joint platform that enables performing a radar function (primary function) and a communication function (secondary function) simultaneously. This duality has become increasingly necessary, since it alleviates congestion and ease competition over frequency spectrum. In this paper, we put forward a technique for information embedding, specifically to multiple-input multiple-output (MIMO) radar employing frequency-hopping chirp (FHC) waveforms. We use FHC codes to implement the primary function (i.e., MIMO radar operation), while embedding communication symbol, for example, phase shift keying (PSK), in each FHC code for secondary function (i.e., communication operation). We show that the communication operation does not interfere with the MIMO radar function. In addition, standard ratio testing is used at the communication receiver to detect the embedded PSK symbols. Furthermore, the waveform designed has the superiorities of high range resolution, constant time domain and almost constant frequency-domain modulus, large time-bandwidth product, and low time-delay and frequency-shift correlation peaks. Numerical results show that: 1) data rates can be accurately detected, and thus, several Mbps are achieved in the system; 2) the SER performance characteristics are significantly improved; 3) the orthogonal frequency-hopping chirp waveforms achieve better range and Doppler resolution with reduced sidelobes levels compared to that of conventional frequency hopping waveforms.