X-band reflectarray antenna with arbitrarily (elliptical) polarization for high-power microwave applications

Abstract

An X-band high-power microwave antenna with arbitrarily (elliptical) polarization is proposed and investigated in this paper. The proposed antenna is founded on a reflectarray composed of printed elements and excited by the microwave energy in the azimuthally symmetric mode. The design procedure starts by calculating the phase difference between rays arriving at arbitrary points on the reflectarray aperture. This phase difference is then compensated by the reflectarray elements to realize the directional radiation of the azimuthally symmetric mode. Square metallic loops inside of a wire grid are used as phase shift elements, and phase variation over the reflectarray aperture is achieved through varying the inside dimension of square loops. An antenna prototype is fabricated to validate the proposed approach. The radiation characteristics of the antenna are measured, and there is a good agreement between simulation and measurement. Measured results show that the boresight gain and axial ratio at 10 GHz are 21.66 dB and 1.4 dB, respectively. The full-wave simulations prove the power-handling capacity of more than 1 MW for this antenna. The proposed antenna is significantly capable for high-power microwave applications, which is due to its compactness, the simple structure, its high-gain and high-power capabilities.