This paper presents the design of a continuous polyharmonic-tuned mode (CPHTM) power amplifier (PA) with an introduced optimal knee voltage waveform control parameter in a continuous harmonic-tuned voltage waveform equation. The optimal knee voltage waveform control parameter works in unison with derived equations, providing bandwidth and efficiency potentials over the limiting factors of the conventional harmonic-tuned power amplifiers (PAs). The effectiveness of the design strategy is proven by the realisation of a CPHTM type-I (CPHTMT-I) PA as compared with a non-continuous polyharmonic-tuned mode type-II (NCPHTMT-II) PA. Test results with continuous-wave (CW) signals show drain efficiency (DE) levels within 53.6%-79% (1.31-2.39 GHz) with 58.4% fractional bandwidth for CPHTMT-I and 64%-78% (1.65-1.95 GHz) with 16.7% fractional bandwidth for NCPHTMT-II. The CW result evidently shows the validation and efficacy of the proposed theory.

Crosstalk is one of the bottlenecks in improving the speed and density of high-speed interconnection systems. In this paper, multi-way and 2-level transmission is changed to one-way and multi-level transmission. Under the condition to maintain the data transmission capacity of the system, the number of microstrip lines is reduced, and the distance between microstrip lines is increased to reduce crosstalk. The simulation results show that over 50% of crosstalk is suppressed in multilevel signal transmission systems.

In this paper a novel robust beamforming method is devised to receive multipath signals effectively. The new algorithm constructs a transformation matrix derived through high-order angle constraint to suppress the interferences with the directions of arrival (DOA) of interference signals. Using the transformed data, the composite steering vector of the multipath signals is estimated as the principal eigenvector of the signal subspace, and then it is utilized in minimum variance distortionless response (MVDR) beamforming to compute the optimal weight vector. The new method is improved in robustness to DOA error by forming wide nulls in incident directions of the interferences, and keeps effective in the presence of coherent interferences. Simulations analyses are provided to illustrate the robustness and effectiveness of the new beamformer.

Jamming and anti-jamming techniques for global position systems (GPS) play important roles in electronic countermeasure. Least mean square (LMS)-based anti-jamming algorithm is widely used in GPS receivers, since it can avoid matrix inversion and has low complexity. For convenience, we call them LMS-GPS receivers. To improve the anti-jamming performance of the LMS-GPS receivers, it is very meaningful to study the jamming technique. Considering that existing jamming signals are easily suppressed by LMS-GPS receivers, a new jamming method named as optimal power difference jamming is proposed in this paper to improve the jamming effect further. Specifically, the analytical relationship between jamming-to-signal ratio (JSR) and the power difference of two interference signals is firstly given. Then, the conclusion that there is always an optimal power difference where the JSR can take the extreme value is drawn. Finally, the optimal power difference is derived as about 22 dB for single-tone interference and 29 dB for band-limited Gaussian noise interference. Simulation results show that the proposed method with optimal power difference is able to improve the JSR remarkably.

A multifunction antenna system providing a radar function and a communication function simultaneously is proposed. The system is composed of a horn antenna whose feeding waveguide is loaded with slots. The horn radiation is used for the main radar function. The slotted waveguide radiation is controlled independently from the horn radiation to perform a direct binary phase shift keying (BPSK) communication provided that each radiating slot is equipped with a simple switching mechanism. Then, the antenna system provides two different functions using orthogonal polarizations and directions. Measured results show 9.1 dB and 32 dB isolation between the two functions at the working frequency. In addition, the proposed system can be integrated with the existing radars which use horns by replacing only the feeding waveguide.

A compact microstrip diplexer based on dual closed loop stepped impedance resonator (DCLSIR) is proposed. The proposed microstrip diplexer is composed of the combination of two DCLSIR bandpass filters (BPFs), which are designed for X-band application. For the demonstration, a dual-channel diplexer has been designed and fabricated using microstrip and printed circuit board (PCB) technologies, respectively. The fabricated diplexer operating at 8.3/10 GHz for X-band application has compact size (15.17 mm x 2.69 mm). The measured results are in good agreement with the full-wave simulation results. Good isolation between two channels is achieved.

A CPW-fed ultra-wideband (UWB) monopole antenna design which exhibits triple band stop functions is demonstrated. The proposed antenna comprises a Split Ring Resonator (SRR) and inverted U slots on a metallic patch to exhibit triple band-notch functions for WiMAX (3.3-3.6 GHz), C-band (3.8-4.2 GHz) and WLAN (5.1-5.8 GHz) bands. The slot width optimization is examined to tune the band-notch resonance frequency, and their effects are exhibited by surface current distributions. The antenna has compact size of 26*30 mm², and it functions over 3 to 11 GHz with VSWR < 2 except notched bands. The SRR loaded dual band-notched antenna and amended inverted U slot integrated antenna both are fabricated and their VSWR, radiation characteristics measured. The antenna demonstrates excellent agreement between measured and calculated results.

In this work FSS (Frequency Selective Surface) based broadband, compact and improved gain microstrip patch antenna with defected ground structure for WLAN and WiMAX applications are proposed. A comparative study has been done by the proposed antenna. It is designed on a Rogers RT/duroid substrate (dielectric constant 2.2, thickness 1.6 mm, and loss tangent 0.0009). The structure of the rectangular patch is 0.10λ₀×0.18λ₀ at 5.5 GHz, where λ₀ is the free space wavelength. The lateral ground plane dimensions are 0.29λ₀×0.27λ₀×0.03λ₀ mm³. A patch type FSS is loaded under the ground plane with separation 10 mm from the antenna. Broad frequency band is obtained along with three resonant frequencies at 5.25 GHz, 6.7 GHz and 11.05 GHz. The achieved frequency band and peak gain are 6.79 GHz (4.93 GHz-11.72 GHz) and 8.82 dBi, respectively. Maximum size reduction of 86% is achieved. The designed antenna is simulated, fabricated and measured to verify the results. The measured results are in good agreement with simulated data. It may be applied in WLAN, WiMAX 5.5/5.8 GHz wireless communication and X band applications.

A compact dual-band metamaterial-inspired antenna is designed and developed in this paper. This design is carried out by loading a radial stub (acts as virtual ground plane) onto a circular microstrip fed patch antenna. Proposed antenna resonates at two frequencies f_c1 = 2.70 GHz and f_c2 = 7.34 GHz with -10 dB simulated impedance bandwidth of 6.6% (2.62-2.80 GHz) and 14.57% (6.57-7.65 GHz) respectively. First band is due to the metamaterial transmission line while second band is due to the coupling between microstrip feed and ground plane. Electrical size of the proposed antenna is 0.27λ₀ × 0.27λ₀ × 0.014λ0₀, where λ₀ is the free space wavelength at f₀ = 2.70 GHz. In addition, this antenna provides antenna gain of 1.49 dB at 2.70 GHz and 3.75 dB at 7.34 GHz in the boresight direction. This antenna also provides dipolar type pattern in the xz plane whereas omnidirectional pattern in the yz plane with cross polarization level of -32 dB in the lower band while cross polarization level of -23 dB is maintained even in higher band. Proposed antenna's compactness, excellent radiation characteristics and ease of fabrication make it feasible to be utilized for Worldwide interoperability for microwave access (WiMAX) and satellite TV applications.

An algorithm called MUSIC-like algorithm was originally proposed as an alternative method to the MUltiple SIgnal Classication (MUSIC) algorithm in order to circumvent requirement on subspace segregation. The relaxation parameter β, which was introduced into the formulation of the MUSIC-like algorithm, has enabled the algorithm to achieve high resolution performance comparable to the MUSIC algorithm without requiring explicit estimation of the signal and noise subspaces. An adaptive framework for the MUSIC-like algorithm was later developed under the α-stable distributed noise environment. In spite of great improvement on target's resolvability performance, a trade-off between such improvement and the estimation bias is inherent. In this letter, two novel directional adaptive β-selection methods for MUSIC-like algorithm under α-stable distributed noise are proposed. The proposed methods aim at reducing estimation bias and noise sensitivity which are inherent in prior adaptive β framework. Simulation results highlight noticeable reduction on the estimation bias as well as the noise sensitivity of the proposed methods without excessive compromise on target's resolvability performance compared with the original adaptive β framework.

Proof-of-concept is presented of a novel slot antenna structure with two excitation ports. Although this antenna provides a wide impedance bandwidth, its peak gain and optimum radiation efficiency are observed at its mid-band operational frequency. The antenna structure is etched on the top side of a dielectric substrate with a ground plane. The antenna essentially consists of a rectangular patch with two dielectric slots in which multiple coupled patch arms embedded with H-shaped slits are loaded. The two dielectric slots are isolated from each other with a large H-shaped slit. The radiation characteristics of the proposed antenna in terms of impedance bandwidth, gain and efficiency can be significantly improved by simply increasing the number of radiation arms and modifying their dimensions. The antenna's performance was verified by building and testing three prototype antennas. The final optimized antenna exhibits a fractional bandwidth of 171% (0.5-6.4 GHz) with a peak gain and maximum radiation efficiency of 5.3 dBi and 75% at 4.4 GHz, respectively. The antenna has physical dimensions of 27×37×1.6 mm³ corresponding to electrical size of 0.0452λ₀×0.0627λ₀×0.0026λ₀, where λ₀ is free-space wavelength at 0.5 GHz. The antenna is compatible for integration in handsets and other broadband wireless systems that operate over L-, S-, and C-bands.

Employing characteristic mode theory (CMT), a shape-first feed-next design methodology for compact planar antennas is proposed, which facilitates rapid and systematic design of self-matched, multi-port antennas with optimal bandwidth and high isolation. First, the optimal antenna shape with multiple self-resonant modes is synthesized using a binary genetic algorithm. Then, the optimal feed positions that provide good input matching and high isolation between the excitation ports are specified using a virtual probe modeling technique. A two-port microstrip antenna with an electrical size of 0.45λ_d×0.297λ_d is designed, fabricated and measured. The measured operating frequency is within 2% of the full wave simulation, and the overall S parameter characteristics and far field patterns agree well with the simulation result, validating our design methodology. Mutual coupling S₂₁ < -30 dB at the center frequency is achieved in this design.

In order to solve the strong coupling problem of a traditional bearingless switched reluctance motor (BSRM), this paper proposes a new type of hybrid excitation double stator BSRM (HEDSBSRM). The new motor can realize self-decoupling between torque and suspension force. In addition, the two degrees of freedom suspension force can also be decoupled. First, the topology of themotoris proposed, and the generation mechanism of suspension force and torque are expounded.Second, the torque winding structure is optimized.Themulti-objective sensitivity optimization design method is used to screen out the key structural parameters that have the greatest influence on the average suspension force, average torque, and core loss. Then, the optimal structural parameters are obtained by the control variable method. Finally, based on the optimized motor, the finite element method(FEM) is used to analyze the electromagnetic characteristics including the suspension force, torque, and coupling of the motor. The simulation results verify the correctness of the proposed design method and analysis of motor performance.

In this paper, we investigate a robust secrecy transmission design for a multiple-input multiple-output simultaneous wireless information and power transfer system. Specifically, considering time switching at the transmitter, we aim to maximize the outage secrecy rate by jointly designing the information signal, energy signal, and time switching ratio, under the constraints of transmit power and harvested energy. The formulated problem is highly non-convex due to the difference of two log-det functions and probabilistic constraints. To overcome this obstacle, we divide the original problem into three convex subproblems. Then, an alternative optimization method is proposed. Finally, numerical results are presented to verify the performance of the proposed scheme.

Propagation of surface waves in dielectric underneath a microstrip patch antenna poses serious hindrance to the radiation mechanism. Several methods are being tried for suppression of surface wave. Metamaterial substrate is presented here with periodic arrangement of metallic cylindrical pins except the area underneath the radiating microstrip patch. The periodic arrangement of metallic cylindrical pins with negative dielectric constant has considerably high reflection coefficient to drive the extraneous surface wave fields towards the fringing fields of the antenna. The textured pin substrate leads to generation of forbidden band gap for the propagation of TM₀ surface wave modes and thus enhances radiation characteristics. The proposed structure proves to be highly beneficial for improving radiation efficiency and gain. Parametric analysis has also been presented for the gain enhancement by varying pin diameter, spacing between pins, and air gap between dielectric substrates. A uniform gain of 10 dB has been achieved for a Left Hand Circularly Polarized (LHCP) microstrip patch antenna. The axial ratio achieved in the described band is 200 MHz. The antenna has been designed for WLAN applications.

In this paper, a compact ultra-wideband (UWB) multiple-input multiple-output (MIMO) spatial diversity antenna with dual band-notches designed on an FR4 substrate (26 × 28 × 0.8 mm³) is proposed and experimentally investigated. The antenna consists of two tapered microstrip feeding lines and two radiating elements. The inverted L-shaped slits are used to introduce notches at WLAN (5.15-5.85 GHz) and IEEE INSAT/Super-Extended C-bands (6.7-7.1 GHz). The isolation more than 15 dB is achieved through the whole working band (2.9-10.8 GHz) by introducing a T-shaped decoupling structure on the ground plane. Furthermore, envelope correlation coefficient (ECC), radiation patterns of the MIMO antenna are also discussed. The simulated and measured results show that the proposed UWB MIMO antenna is a good candidate for UWB diversity applications.

This research explores a silica based highly nonlinear photonic crystal fiber of near infrared window; solid silica core photonic crystal fiber is suitable for propagating light towards the near-infrared wavelength region. Full vector finite difference method is used for numerical simulation, by solving the generalized nonlinear Schrödinger equation with the split-step Fourier method to show that the design exhibits high nonlinear coefficient, near zero ultra-flattened dispersion, low dispersion slope and very low confinement losses. It is demonstrated that it is possible to generate high power wide supercontinuum spectrum using 2.5 ps input pulses at 1.06 μm, 1.30 μm and 1.55 μm center wavelengths. It is observed that supercontinuum spectrum is broadened from 960 nm to 1890 nm by considering center wavelengths of 1.06 μm, 1.31 μm, and 1.55 μm into silica based index guiding highly nonlinear photonic crystal fiber. Furthermore, immensely short fiber length of 1 m at center wavelengths of 1.06 μm, 1.31 μm and 1.55 μm is possible using the proposed highly nonlinear photonic crystal fiber. The generated high power wide supercontinuum spectrum is applicable as a laser light source in near infrared band.

The aim of this paper is to introduce a new kind of reflectarray cell with both amplitude and phase control abilities. A slot is added in the ground of an arbitrary conventional cell for this purpose. A slotted cell having a square patch is investigated to verify the effectiveness of the proposed approach. This cell is used to reduce the side lobe level of a reflectarray antenna.

To enhance the accuracy of estimated rotor position for sensorless controlled permanent magnet synchronous motor, the strategy based on sliding mode observer (SMO) with dual second order generalized integrator (DSOGI) is proposed. The SMO is utilized to estimate the back electromotive force (EMF). Considering the estimated back-EMF harmonics resulting from both flux spatial harmonics and inverter nonlinearities, the DSOGI is applied to eliminate multiple orders harmonics and extract the fundamental wave of the estimated back-EMF for calculating the rotor position. Therefore, the DSOGI can effectively reduce the influence of the estimated back-EMF harmonics and improve the accuracy of rotor position estimation. In addition, the software quadrature phase-locked loop with back-EMF normalization is utilized to calculate the rotor position in order to eliminate the influence of the changed back-EMF magnitude at different speed. Finally, to illustrate the effectiveness of the proposed strategy, the experimental platform of an open-winding permanent magnet brushless motor is built. The comparison results verified that the drive system performance of both steady state and dynamic state is improved.

This paper presents a dual band circular microstrip patch antenna with an elliptical slot for future 5G mobile communication networks. The antenna has resonating frequencies of 28 GHz and 45 GHz, with bandwidths of 1.3 GHz and 1 GHz, respectively. Efficiency of the antenna is 85.6% at 28 GHz and 95.3% at 45 GHz. The return loss at 28 GHz is -40 dB, with maximum gain of 7.6 dB while at 45 GHz return loss is -14 dB with maximum gain of 7.21 dB. The antenna is designed on a Rogers RT5880 (lossy) substrate with dielectric constant of 2.2 and loss tangent (tanδ) of 0.0013. The antenna has compact size of 6×6×0.578 mm³. Array is used to achieve 12 dB gain, required for mobile communication. The proposed array has resonance frequencies of 28 GHz, 34 GHz and 45 GHz with maximum gain of 13.5 dB and radiation efficiency of 98.75%. Centre series fed technique is used for the excitation of array. SAR value of array antenna obtained at 28 GHz is 1.19 W/kg, at 34 GHz is 1.16 W/kg, and at 44.2 GHz is 1.2 W/kg. CST Microwave Studio, a 3D simulating tool, is used for the antenna design and calculation of the antenna parameters along with the SAR analysis.