Compact and Lightweight Additive Manufactured Parallel-Plate Waveguide Half-Luneburg Geodesic Lens Multiple-Beam Antenna in the K$_{\mathrm{a}}$-Band

In this letter, a parallel-plate waveguide half-Luneburg geodesic lens multiple-beam antenna optimized for additive manufacturing is designed and validated experimentally in the K
$_{\mathrm{a}}$
-band. Two prototypes were manufactured in AlSi
$_{10}$
Mg through laser powder-bed fusion and measured in an anechoic chamber. The compact and lightweight prototype optimized for additive manufacturing demonstrates excellent RF performance while significantly reducing mass and mechanical complexity. Specifically, misalignment errors present in previous studies are solved, improving sidelobe level by up to 10 dB. A maximum realized gain of 22.1 dBi is measured at 28 GHz. This single-piece, compact, and lightweight design is particularly attractive for applications having mass restrictions and limited space like millimeter-wave systems on board small satellites.