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A novel frequency reconfigurable microstrip antenna based on (BST) substrate is presented. Compared to the complicated structures in traditional reconfigurable antennas, our work is featured by a quite concise design. A theoretical model is proposed to calculate the initial antenna parameters. Both the simulation and the experiment indicate that the coupled aperture structure can efficiently overcome impedance mismatch of BST substrate and obtain a frequency tunability of 10% in Ku band by a DC electric field changing from 0 to 10 m. Besides, similar radiation patterns are obtained in the operating band for both the E plane and H plane. Our study shows that the using of BST material on the frequency reconfigurable antenna is promising, and can be easily extended to reconfigurable antenna arrays.Index Terms-BST substrate, DC electric field, frequency reconfigurable antenna, ku band.

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In this study, the synthesis of scanning beam pattern with antenna selection for practical half‐circular conformal array is achieved based on hybrid particle swarm optimisation‐gravitational search algorithm (PSOGSA). A half‐circular conformal dipole antenna system has been designed, fabricated and tested. The antenna element is dipole, and the digital beam forming net can control both the amplitude and phase in each channel through attenuator and phase shifter. The array confirms to a surface of half‐circular metal carrier. To achieve the synthesis of scanning beam pattern with activated antenna selection, hybrid PSOGSA is introduced to optimise the excitation amplitude. To consider the mutual coupling effect, embedded element pattern is measured and utilised. Numerical comparisons and practical experimental results illustrate the advantage and accuracy of the proposed method and manufactured system in the synthesis of scanning beam and activated element selection.

A slab lens antenna has been designed to enhance the directivity of a horn antenna efficiently in a wide range of frequencies. A gradient refractive index metamaterial is utilized to compensate phases of electromagnetic waves radiated from a horn, which can transform the cylindrical wave into a plane wave. To obtain broadband property, the gradient refractive index metamaterial composed of cross-shaped conductor, which works in a nonresonant status is designed, and the metamaterial is proved to be broadband, polarization insensitive, and lossless. The slab lens is designed by a collection of metamaterial unit cells with different geometric parameters, where the effective refractive index of the unit cells are determined by the size of cross-shaped conductors to form the required inhomogeneous refractive index distribution. The simulation and experiment results show that the lens located in front of a horn can considerably compress the antenna's radiation patterns over a wide band range from 12 to 18 GHz.ABSTRACT: This article presents an optical single sideband (SSB) signal generation in radio over fiber system using a polymeric microring resonator as an optical notch filter, alleviating the fiber chromatic