Efficient mm-Wave Antenna-On-Chip through Effective Illumination of Integrated Artificial Magnetic Conductor

Artificial magnetic conductors (AMC) employed underneath the antenna-on-chip (AoC) can provide the in-phase reflection as well as the isolation from the lossy silicon substrate. The gain of an AMC-backed AoC is proportional to the AMC area. However, the relatively large AMC cannot be illuminated effectively due to the limited space in the stack-up. This means the AMC-backed AoC cannot achieve its optimum performance. In this paper, we propose to resolve this issue through custom-designed coupling enhancement structures (CESs), which enable the energy coupling from the well-illuminated unit cells (in the center) to the less or non-illuminated unit cells (at the peripheries). Compared to a conventional AMC, the proposed CES-based AMC enhanced the AoC gain by 3.5 dB and radiation efficiency by 23% at 94 GHz. The fabricated prototype of the proposed AMC-backed AoC demonstrated a gain of 9.8 dBi which was 25 times greater than an AoC without AMC.