The paper is focused on reliable modeling and analysis of the effects connected with the resonant transformation of the field of a plane and density-modulated electron beam flying over the periodic rough boundary of a natural or artificial medium. In the paper such a medium occupies a part of the half-space, limited in thickness. Therefore, the numerous effects appeared due to transverse (in the thickness of the periodic structure) resonances, and the coupling of eigen regimes of two different periodic interfaces also contributes to the anomalies appearing due to excitation of the surface eigen waves of the periodic boundary interface that had been discussed in previous papers of this series.....

This research paper presents a wideband hook shaped aperture coupled circularly polarized antenna for 5G application. It consists of three layers; a radiating copper plate (0.5 mm) as a top layer, a foam material of 2 mm thickness as a middle layer, an FR4 substrate with hook-shaped apertures in the ground plane, and a bent feed line as the bottom layer. The performance characteristics of the proposed design are improved by feeding mechanism, which entails the use of a bent shape microstrip line coupling through four hook shaped slots to generate four sequentially phased sources to excite the single layer patch antenna. The proposed antenna exhibits return loss bandwidth of 29.10% (2.8-3.81 GHz), axial ratio bandwidth of 13.47% (3.61-4.11 GHz), and cross polarization level is 20 dB which is attained at boresight and Gain of 4.08 dBic at the resonant frequency of 3.47 GHz. The proposed antenna design is fairly applicable to 5G radio band and discussed about the azimuth, elevation patterns and surface current distribution in frequency band of interest. The proposed design is simulated using High frequency structure simulator (v.13), and measured results are in good agreement with simulated ones.....

In order to improve the performance of decoupling control for an interior permanent magnet synchronous motor (IPMSM), a recursive least square algorithm with fuzzy forgetting factor is proposed to identify IPMSM parameters. Firstly, the problems of coupling and parameter identification of IPMSM are analyzed. Secondly, the identification process of resistance and flux linkage is analyzed, and the static parameters are identified as the initial value or constant value. Thirdly, fuzzy control is used to dynamically adjust the forgetting factor in the recursive least square algorithm to make the identification of direct axis and quadrature axis inductance parameters more accurate. Finally, the effectiveness and accuracy of the proposed parameter identification algorithm are verified on the platform, and the good performance of the proposed algorithm in decoupling control is verified. The experimental results show that the identification method can accurately identify the motor parameters in static state and dynamic state. At the same time, the forgetting factor is dynamically adjusted to improve the parameter identification effect and decoupling control performance of the motor.....

This paper presents a planar filtering magic-T with a simple structure. It consists of four half-wavelength microstrip resonators with one loaded with a shorted microstrip stub at its central location. The resonator loaded with a shorted microstrip stub has the even-symmetry resonant mode. Other three resonators have the odd-symmetry resonant mode. The planar filtering magic-T has four ports, which all adopt a tapped line structure. Its novelty lies in the simple structure. Compared with previous works in the literature, its inter-resonator coupling zones are apart away and have no influence on each other, which means a simple design. Furthermore, a different-properties coupling is not needed, and its filtering response can be easily extended to the high-order case. The operational mechanism and design method are introduced in details. A planar filtering magic-T with center frequency of 920 MHz was designed and fabricated. The measured results show that, at the center frequency, the return losses (S₁₁/S₄₄) is less than 20/12 dB; an isolation degree of 25 dB (S₄₁) can be observed; the insertion loss of the difference port (S₂₁/S₃₁) and sum port (S₂₄/S₃₄) are 4.5/4.7 dB and 4.3/4.6 dB; the phase unbalance is 8˚/7˚(Σ/Δ). Totally, these results can verify the effectiveness of the proposed novel planar fiiltering magic-T.....