Effective method to design large‐size horn arrays with high gain and suppressed sidelobes using meta‐screens

Abstract

This study presents a novel design of a high gain and suppressed sidelobes horn array covered with meta-screens. The meta-screens are composed of two layers of periodic slot structure that divide the large-size horn into an equivalent leaky-wave array. A synthesis procedure is therefore proposed to analyse the leaky-wave array, resulting in high gain and low sidelobes. The element pattern of the leaky-wave array is derived from the equivalent network of the corresponding leaky-wave antenna, and the element excitations are determined by the scattering results from the horn aperture field distribution. The synthesised pattern of a horn with the meta-screens is calculated by using the element pattern and excitations. Based on the synthesis procedure, the optimised horn and meta-screens with a uniform aperture field are achieved efficiently. Adopting the horn and meta-screens in an arbitrary N × N array, the array demonstrates a high gain and suppressed sidelobes. To verify the proposed method, a 2 × 2 array prototype is designed and fabricated. The prototype features the gain of 27.4 dB and the sidelobe level less than -10 dB. A good agreement between the predicted and measured results proves the effectiveness of the method.