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The aim of this paper is proposing a new fast designing method for planar graphene leaky‐wave antennas without periodical changes. Thus, Floquet theory cannot be used for designing, an optimization in numerical EM solver is needed. Since leaky‐wave antennas are electrically long, their simulation using commercial EM simulators needs a large number of meshes, also the optimization of the large number of parameters (slot lengths and their distances) needs huge amount of memory and computation time. To resolve this problem, the method of Moments, implemented in MATLAB, which has been accelerated by applying some techniques, has been used in the design procedure. The antenna comprises a slotted graphene micro ribbon with a specific pattern, which is placed on two dielectric substrates and a PEC reflector. Graphene is used in the proposed LWA, instead of the electric conductor, because of its wonderful properties. The suitable pattern of slots on the graphene microstrip, is obtained using optimization by MATLAB Genetic algorithm tool. The usefulness and performance of the proposed designing approach, is verified in one example. It has been shown that the presented antenna, compared with one of the new successful similar antennas, has a better gain, radiation efficiency, and a wider range of beam scanning.

Abstract:In this paper a new method has been presented to design spatial band-pass filters consisting of dielectric backed conducting strips. This approach uses an equivalent circuit model in which determined inductive elements are spaced at intervals about half wavelength. To realize the proposed method, the inductive elements have been replaced by dielectric backed conducting strips located at intervals about half wavelength. Half wavelength transmission line sections act as resonators. In this manner the wideness and spacing of strips in each dielectric backed conducting strip, as well as the distance between them, is determined by fitting the characteristic (transfer function) of the proposed filter to that of a desired one obtained from an equivalent circuit model. To take the effect of higher order modes (evanescent mode), a coupled set of magnetic field integral equations is derived and formulated. Finally a set of linear matrix equations are solved using method of moments (MoM) and entire basis functions have been used resulting in rapid convergence.The usefulness of the proposed structure and its performance are verified by designing and simulating an equal ripple Chebyshev-type and a Butterworth-type spatial band-pass filter.