High frequency electromagnetic (EM) fields in the focal region of a 3D elliptical reflector placed in a homogeneous and reciprocal chiral background have been analyzed using geometrical optics (GO) approximation and Maslov's method. The GO solutions becomes invalid at the focal region of a 3D elliptical reflector due to unreal singularities. Therefore, an asymptotic method based on Maslov's theory has been applied to derive high frequency EM fields, which is also valid at the focal points. Moreover, the effect of chirality parameter of the background medium on the position of focal points for both Left circularly polarized wave (LCP) and right circularly polarized (RCP) wave are described by plotting the derived expressions numerically using MATLAB.

A novel balanced antipodal Vivaldi antenna (BAVA) with high gain and good directivity is proposed in this paper. The outer edges of the flare are modified by a binomial curve to broaden the impedance bandwidth. A metal director is adopted to improve the antenna gain and directivity. The measured results show that the proposed BAVA achieves a bandwidth from 2 to more than 40 GHz with peak gain >0 dBi and >10 dBi over the 8-40 GHz range. The squinting beam of E-plane is less than 5° from 4 to 40 GHz and less than 3° from 22 to 40 GHz.

This paper focuses on electromagnetic exposure to control insect pests in agriculture using parallel plate applicator. A tomato plant and ``Helicoverpa armigera'' eggs and larvae are exposed to 915 MHz and 2450 MHz. A parallel plate applicator is fabricated and matched with Radio Frequency and Microwave source at 50 Ω. The power up to 250 W was applied to parallel plate applicator in an anechoic chamber to observe the behavior and heating effect on commodities inside the applicator. The rise in temperature of the tomato plant and tomato with insect pest stages were different for different dielectric properties. The reduction in the hatching was observed after the exposure. The first instar to fifth instar larvae erratic movement was observed during exposure. The faster response of heating was observed at the higher side of exposed power. The effect on the heating rate considering the variations in the space between two parallel plates of the applicator is analyzed in this research. The parallel plate capacitor is referred to as an applicator in this paper.

This paper presents the design flow of a compact GaAs MMIC for Extremely High Frequency (EHF) satellite communications. The proposed circuit enables sub-harmonic mixing capability and integrates a LO buffering section, thus allowing for low frequency and low power reference signal interface. Circuit design is described in detail providing a comprehensive view of the followed theoretical approach, starting from mixer core definition until the complete synthesis of LO/RF/IF interfaces. In particular, the design flow of an innovative three-conductor Marchand balun is deeply analysed. Fabricated MMIC operates in the 43.5-50 GHz band and results in a compact layout (2.4x2.4 mm²) featuring a port-to-port isolation better than 25 dB with a typical conversion loss of 12 dB.

A circular monopole antenna for ultra wideband (UWB) applications with triple band notches is proposed. The proposed antenna rejects worldwide interoperability for microwave access WiMAX band (3.3 GHz-3.8 GHz), wireless local area network WLAN band (5.15 GHz-5.825 GHz) and X-Band downlink satellite communication band (7.1 GHz-7.9 GHz). The antenna utilises mushroom-type and uniplanar Electromagnetic Band Gap (EBG) structures to achieve band-notched designs. The advantages of band-notched designs using EBG structures such as notch-frequency tuning, triple-notch antenna designs and stable radiation pattern are shown. The effect of variation of EBG structure parameters on which notched frequency depends is also investigated. Fabricated and measured results are in good agreement with simulated ones.

This paper proposes a planar monopole antenna design for achieving gain enhancement. The radiation pattern is achieved straightforwardly by employing a detached glass slab and placing a reflected metal slab after the glass slab onto the antenna structure. Geometrical parameters were examined to optimize the performance of the proposed antenna. Such a configuration causes constructive interference between the incident and reflected fields. The radiation patterns can be adjusted the thickness of the glass slab and dielectric constants. The radiated fields are redistributed because of the inclusion of the glass slab, which has a permittivity of ε_r = 7.75 and a thickness of h = 1 mm. Consequently, the planar monopole gain achieved using the glass slab and reflected metal slab is increased to approximately 5 dBi, whereas the antenna resonant frequency remains almost unchanged at nearly 14% in impedance bandwidth. The results obtained for the directional pattern, return loss, gain, and radiation efficiency of the proposed antenna were analyzed. The antenna volume of the radiation area and ground plane was 3 × 32 × 52 mm³. Detailed simulations and experiments were conducted to optimize the gain enhancement operations, and the measured results agreed with the simulated ones.

The most general electromagnetic boundary, defined by linear and local boundary conditions, is defined in terms of conditions which can be called generalized impedance boundary conditions. Requiring that the boundary be equivalent to PEC and PMC boundaries for its two eigenplane waves, which property is known to exist for many of its special cases, it is shown that the recently introduced Generalized Soft-and-Hard/DB (GSHDB) boundary is the most general boundary satisfying this property.

Interior bearingless permanent magnet synchronous motors (IBPMSMs) are a new type of machines having two sets of windings in the stator, offering no lubrication and no mechanical friction, high efficiency, robust rotor construction, hybrid torque production nature and flux-weakening capability. In this paper, the suspension force modeling and the static electromagnetic characteristics of an IBPMSM are studied. The suspension force model of the IBPMSM is established and investigated based on the Maxwell tensor method. And then the static electromagnetic characteristics, including permanent magnet (PM) flux linkage, EMF, inductances, electromagnetic torque and suspension force, are discussed with the finite element analysis (FEA) method. The electromagnetic characteristics of the IBPMSM are very helpful for the design and optimization of the motor. The effectiveness of the proposed suspension force mathematical model is verified by comparing the theoretical results with FEA-based predictions. The work in this paper lays an important foundation for the optimization design and control strategies of the IBPMSM.

A double printed rotated quadrilateral dipole UWB antenna for wireless communication is presented. The rotation of quadrilateral and modification of integrated balun structure is employed to enhance bandwidth and impedance matching. The proposed antenna shows impedance bandwidth of 3.8-18.1 GHz which covers the entire C, X and Ku bands. The Radiation patterns of the designed antenna structure are relatively stable and omnidirectional over the entire obtained bandwidth with an average gain of 3.6 dB. A good agreement is found between the simulated and experimental results. The proposed antenna has a simple design, comparatively compact size and more bandwidth than previous reported double rhombus antenna.

A wideband circularly polarized (CP) slot array with high radiation efficiency is proposed. The cavity-backed square slots are designed to achieve wideband CP radiation with a unidirectional pattern. The slotted waveguide is adopted to feed the array with high efficiency. The square slot, cavity and feeding slot in the waveguide can be viewed as a radiating element. A CP slot array can be conveniently designed as traditional waveguide slot arrays, once the element admittance characteristic is determined. A 1-by-8 CP array operating at 12.5 GHz has been developed. Measured impedance bandwidth of 6.9%, axial-ratio (AR) bandwidth of 8.8% and a gain of 15.4 dBi have been achieved. This array can be conveniently expanded to a larger wideband CP array with a higher gain, which is preferred for the specific satellite communication applications.

The purpose of this paper is to theoretically investigate the properties of electromagnetic wave propagating in both one-dimensional periodic and quasiperiodic photonic crystals consisting of high-temperature yttrium barium copper oxide and strontium titanate dielectric nano-scale materials in the ultraviolet wavelength region. By using the transfer matrix method, angle-, polarization- and thickness-dependences of created PBGs are explored individually for periodic and quasiperiodic structures, and some interesting features are presented in the results section. Such supposed structures can be acts as very compact polarization sensitive splitters and defect-free multichannel narrowband tunable filters.

This paper proposes sensors based on the time-domain reflectometry (TDR) technique for qualifying ethanol fuel. Four different probe geometries were proposed: bifilar, microstrip, coaxial, and helical. All probes allowed qualification of ethanol adulterated with water. Helical probe showed the best response. Thus, this proposal contributes to the development of electronic tongues.

A W-band dual-polarized Cassegrain antenna for cloud radar is proposed. The aperture diameter of the main reflector of the antenna is 50 cm. By using a modified Magic-T structure in the feed horn, the antenna is dual-polarized with high port isolation. The measured results show that the port isolation is 44.7 dB. The gains are 47.3 dB and 49.5 dB for the two ports at 94 GHz, respectively, and the efficiency of the antenna is better than 87%.

This paper presents the design and analysis of guided wave notch filters using the Lagrangian formulation for metamaterials. It is shown that the application of the Lagrangian is a convenient and effective way to select an appropriate filtering structure and determine the necessary configuration for desired filter performance. A WR-187 waveguide horn antenna is investigated with notch filters composed of broadside coupled and gap coupled split ring resonators. It is shown that broadside coupling offers significant tunability in a compact size. The filter exhibits an operational bandwidth from approximately 3.9-5.7 GHz with 40-150 MHz of instantaneous bandwidth. The fabrication of the horn antenna and split ring resonators is presented along with simulated and measured data that confirms the approach.

A 2×2 circularly polarized (CP) MIMO antenna is proposed to resonate at 5.8 GHz IEEE 802.11 WLAN band for non-line of sight (NLOS) communication. The proposed design achieves circular polarization with two optimized 90˚ apart rectangular slots etched at the center of a truncated rectangular patch. The proposed MIMO covers 5.49-6.024 GHz frequency band. The achieved isolation between two ports is more than 33 dB. The gain at the 5.8 GHz resonant frequency is 5.34 dBi. The diversity performance in terms of gain, ECC, and MEG has been reported.

This paper presents a double-stator permanent magnet generator (DSPMG) integrated with a novel magnetic gear structure which is proposed to be used as a direct drive generator for low speed applications. Torque transmission is based on three rotors consisting of prime permanent magnet poles on the middle rotor and field permanent magnet poles on the inner and outer rotors, respectively. The proposed machine combines the function of a triple rotor magnetic gear and electrical power generator. The operating principle of the generator is discussed, and its performance characteristics are analyzed using 2-dimensional finite-element method (2D-FEM). Analysis results about its magnetic gear ratio, transmission torque, cogging torque and electrical power performance are reported. The 2-D finite element analysis results verify the proposed generator design.

In the general framework of intelligent transportation, the increasing use of information communication technology in full or hybrid electric vehicles requires careful assessment of electromagnetic compatibility, with specific reference to the conducted emissions (CE) generated by the inverter in a broad frequency range (10 kHz-100 MHz). To this aim, this work reports a modelling approach for the prediction of CE in electric powertrains, which is based on circuit representation of each single subsystem, that is, the battery, the inverter, the three-phase synchronous motor, and the power buses composed of shielded cables. The proposed models are able to represent both low-frequency functional aspects and high-frequency parasitic effects of paramount importance for CE analysis, and can be implemented into a Simulation-Programme-with-Integrated-Circuit-Emphasis (SPICE) solver. The proposed modelling approach is exploited to simulate virtual CE measurements according to international standard CISPR 25, and to investigate the impact of setup features, including grounding connections of shields, the propagation of CE in electrically long power buses, the operating point (power, torque, speed) of the motor-drive system.

A compact coupled-fed monopole handset antenna with multi-frequency band operation is proposed in this paper. It occupies a no-ground space of only 26×14mm², and two wideband operations can be achieved by the coupled-fed two opposite-direction spiral branches. The low frequency bands of LTE700 operation are achieved by two spiral branches' 0.25-wavelength monopole modes, which generate a dual-resonance mode at 740 and 780 MHz. At around high frequency ranges, a 0.25-wavelength monopole mode of a T-shaped monopole is generated at 1.75 GHz, and combined with two 0.75-wavelength high-order monopole modes of the left and right side spiral branches to cover the DCS1800/PCS1900/UMTS2100/LTE2300/2500 bands. In addition, the proposed antenna is easily printed on the dielectric surface of a low cost FR4 substrate, which makes it suitable for practical mobile applications. The proposed antenna is successfully simulated, fabricated, and measured to validate the design.

A method for extracting a desired network from the composite measurement of a desired and undesired networks combination is proposed. The desired network is required to be a reciprocal and passive network. Time-domain responses are chosen by time-domain gates according to the signal flow diagram of the measured networks. This method can be used to characterize fixtures and de-embed of fixtures effects from the composite measurement of a device under test (DUT) and fixtures combination. This method can also compensate for masking errors. Extraction for the S-parameters of the desired network are described in detail, and the extraction result is validated with two simulations.

We report the modelling and characterization of microwave absorbing materials specially designed for 26-37 GHz frequency range (Ka-band). Composite materials based on carbon nanotubes/BaTiO₃/Fe₃O₄ in a phosphate ceramic matrix were produced, and their electromagnetic response was investigated. Both theoretical and experimental results demonstrate that this material can absorb up to 100% of the power of an incident plane wave at a normal incidence angle. The physics underlying such absorption level is discussed in terms of refractive index of the material.