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

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.