Grating Lobe Suppression of Large Element Spacing Array by Angle Selective Surface
Haotong Wang, Shi‐Wei Qu, Shiwen Yang
Abstract
In this paper, a large element spacing array antenna with a regular square lattice and simple structures is proposed, which adopts a simple grating lobe suppression approach by loading rectangular cavities and an angle selective surface. The proposed array antenna can achieve ±15° scanning in the H-plane with active VSWRs below 2.5 within 9.2∼10 GHz, and has an element spacing of 0.96 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ<sub>c</sub></i> (where <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ<sub>c</sub></i> is the free-space wavelength at the center operating frequency, i.e., 9.6 GHz). Additionally, the utilization of rectangular cavities and the angle selective surface effectively reduces the gains of the grating lobes by more than 13 dB compared to those of the main lobes. As a result, the gains of the grating lobes are at the same level as those of the first sidelobes, indicating a good grating lobe suppression effect. Finally, a 7 × 5 array prototype is fabricated to validate the proposed design, and a good agreement is achieved between the measured and calculated results.