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This paper proposes computing the mutual impedance of a multi-layer patch fed by a slotted waveguide using the combined equivalent electric and magnetic dipole-moment method and conventional moment method (EDM-MOM) as an efficient technique. The slot, PEC, and dielectric regions are substituted with equivalent currents. The unknown currents are expanded using the Rao-Wilton-Glisson and Schaubert-Wilton-Glisson basis functions. The matrix equations are then extracted from the boundary conditions. Using the EDM, each RWG or SWG of the PEC and dielectric is equivalent to an infinitesimal electric dipole, and that of the slot is equivalent to a magnetic dipole. The element matrix related to the waveguide excitation is calculated using the conventional moment method due to simple integration and accuracy. Further, the superposition of the mutual coupling between each equivalent electric or magnetic dipole in the first element and each dipole in the second element is used to obtain the mutual impedance of the two elements of the waveguide slot-fed patch array. The proposed method shows good agreement with CST software simulation results. [ABSTRACT FROM AUTHOR]

This paper presents an efficient method of computing resonant length and admittance characteristics of an isolated broad-wall shunt slot, radiating between baffles of finite height. The outer three-dimensional (3-D) field problem associated with this geometry is reduced to a two-dimensional (2-D) one via a Fourier transformation with respect to the longitudinal z direction. For each value of the longitudinal wave number k(sub z) an integral equation is solved for the E field in the mouth of the plates using the method of moments. This procedure is repeated for several discrete values of k(sub z), to obtain a spectrum of 2-D solutions which are then inverse-transformed to construct the 3-D solution in the spatial domain for the exterior baffle region and the half space. The slot aperture field is determined by the conventional moment method solution to the integral equation that enforces the continuity of the H field across the slot. Scattering properties of the slot are then deduced. Numerical results for the resonant length and resonant conductance are presented. Computed results are found to be in good agreement with experimentally measured data.

In this study, the authors propose a new idea to employ mantle cloaking in order to reduce the mutual coupling between electrically small antennas (ESAs) placed on man-pack radio systems. They determined and numerically optimised the parameters of the mantle cloak on loop and monopole antennas; these antennas are to provide near vertical incidence skywave (NVIS) and ground wave high frequency (HF) communication in man-pack radio systems. The authors' designed cloak can effectively minimise the mutual coupling between the ESAs - in the man-pack radios - for only a very small impact on the antenna's radiation characteristics. The authors believe that these improvements pave the way toward effectively applying these compact radio structures in emergency HF communication in areas with limited access to conventional communication links. [ABSTRACT FROM AUTHOR]

This paper presents a very fast and highly efficient full-wave hybrid method for analyzing an integrated dielectric lens antenna (ILA) fed by multilayered substrate-integrated waveguide (SIW) slot antenna/array. The feeding antenna structure is modeled as a stacked parallel-plate waveguide with metallic posts, coupling, and radiating slots. Physical optics method in conjunction with three-dimensional ray tracing technique is employed to analyze the effect of the dielectric lens on the SIW feeding slots. Fields in the SIW structure are computed by considering the Dyadic Green's function expressed as an expansion of vectorial cylindrical eigenfunctions and taking into account scattering at the conducting posts. Slots are modeled with equivalent magnetic currents expressed as a sum of domain basis functions. By imposing continuity of the tangential components of the fields an integral equation is obtained that is solved with the application of method-of-moments. In order to validate the proposed technique, a hemispherical ILA fed by a double-layered SIW cavity which is backed with slot antenna is analyzed. Excellent agreement is obtained with HFSS software together with significant improvement in computational time and memory requirements. [ABSTRACT FROM PUBLISHER]