ALPSS: A millimetre-wave aperture-coupled patchantenna on a substrate lens

Abstract

The feasibility of millimetre-wave (mm-wave) aperture-coupled patch antennas, printed at the back surface of substrate-lenses is demonstrated and the corresponding radiation characteristics are investigated. A specific realisation of such an air-lens-patch-slot-strip (ALPSS) antenna on a low-permittivity ɛr = 4.0 extended hemispherical lens substrate is theoretically and experimentally characterised at 70 GHz. It is demonstrated that the ALPSS antenna exhibits clean, axially symmetric patterns of low cross-polarisation (–26 dB), a directivity of 30.4 dB and the 3 dB pattern full-beamwidth remains within 6°–5° between 60–80 GHz. In addition, a very-high front-to-back (F/B) ratio, of the order of 50 dB is measured at 70 GHz, despite the absence of a backing ground-plane. The ALPSS antenna is well suited for low-cost broadband point-to-point communications and collision avoidance applications.