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In this work, the effect of the fabrication uncertainties on the substrate thickness on the radiation performance of the reflectarray antenna is addressed. An interval analysis (7A)-based method is used to compute the upper and lower bounds of the power pattern as a function of the deviations in the substrate thickness. The Minkowski Sum (MS) is exploited to combine interval phasors in order to mitigate...
An extensive study is conducted to evaluate breakdown mechanisms in gallium nitride (GaN) high electron mobility transistors (HEMT). A comprehensive physics-based model of a common HEMT provides the base comparison to conduct different material and geometric investigations. The variations are evaluated in a progression toward the optimal configuration: 1) varying the passivation material, 2) replacing...
This paper presents a multi-mode, planar array made up of co-located elements. The array operates in dual-bands, S- and X-band, with dual-polarizations. The dual-band operation necessitates different electrical spacing between the S-band and X-band array elements. We optimize the electrical spacing by co-locating dual-band radiating elements with X-band only elements. The enabling technology for the...
In this paper, we designed, simulated, built and test ‘E-shaped patch antenna with five resonances’ that gives 9 dB radiation pattern gain. Our simulation and experimental investigation aimed to understand the behavior of the two slits. The first frequency is 4.64GHz with 8.5dB gain the second frequency is 5.3GHz with 7.10dB gain, the third frequency is 10.1GHz with 9dB, the fourth is 12.9GHz with...
In this paper, a speeding up technique is proposed to reduce the computation time of the lossy anisotropic (Lossy-ANI) algorithm integrated into the FDTD method. This algorithm is applied to a line-fed microstrip patch antenna (MPA) with anisotropic substrate and a Lossy-ANI scattering object. Numerical results show that the anisotropy effects the resonant frequencies of the MPA and the RCS of the...
A suspended plate antenna (SPA) with L-probe feed is of interest as an efficient non-contacting feed method. It maintains high efficiency even when the plate is constructed of poorly conducting materials such as conductive inks. An SPA is designed at 10 GHz where fabrication tolerances can have an impact on performance. The SPA as designed has 36 percent impedance bandwidth and 8 to 9 dBi of gain...
The variational analysis to solve the propagation constant of substrate-integrated waveguides with a longitudinal slot is presented in this paper. A closed-form expression for the stationary equation is given, which is solved using a well-known root-searching Newton's process. Compared to the transverse resonance method, the present analysis does not require the values of the edge impedances and thus...
A reconfigurable electrically small microstrip-fed antenna composed of a broadside coupled split ring resonator with stubs connected through pin-diodes and an exciting arc-shaped monopole is presented. Numerical and experimental results are presented for an antenna configuration of 1/24.3 wavelength λ in diameter (antenna is inscribed in a sphere with radius a, k — wave number), ka = 0.13. The antenna...
The ability of graphene and other nm-thin carbon films including pyrolytic carbon (PyC) and pyrolyzed photoresist (PPF) to absorb microwave radiation is discussed. We show that being deposited on a properly chosen optically transparent dielectric substrate these films can provide more than 20 dB electromagnetic interference (EMI) shielding efficiency (SE).
In this paper, we propose a metamaterial absorber for dual-band applications. The unit cell of the proposed absorber consists of a cross H-like structure within a metal square ring and a ground plane, which are printed on both sides of the substrate. The results show that our designed absorber gives two absorption bands at 5.6 GHz and 13 GHz, and the absorption peaks are both higher than 99%. The...
Models, based on variational principles, provide for multiple features which of key importance for computational implementation. Based on this vision, we combine the Gibbsian thermodynamic (variational) method for heterogeneous systems with electrostatics. The substances under study are those which are able to accumulate free (i.e., not dipolar) electric charges. We announce several key formulas related...
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