A 24 GHz circularly polarized on-chip antenna for short-range communication application

This article presents a design method for a miniaturized, Circularly Polarized (CP), concentric ring-shaped monopole on-chip antenna for 24 GHz short-range application. The proposed antenna covers a 22-29 GHz automotive radar spectrum with a resonance at 24 GHz. Taking a simple circular ring-shaped patch as the reference antenna, this study introduces a small gap in the closed-loop structure that helps provide the required travelling wave current distribution to realize the CP property. Then, a smaller circular ring is incorporated inside the reference antenna to improve the antenna performance in terms of the CP characteristics. Finally, the proposed antenna is tuned to obtain the CP characteristics in the desired band ranging from 23.2 GHz to 27 GHz with 3-dB with Axial Ratio (AR) bandwidth of 3.8 GHz. It offers a maximum gain of -4.5 dBi and wide angular range coverage (HPBW > 75 degrees in both E and H-plane). The standard CMOS process with only one level of mask (metal patterning) is used to better understand the functions of the designed antenna. Compact size (3.8 mm x 4 mm x 0.678 mm), simple design layout, and high performance make the antenna a suitable candidate for System-on-Chip (SoC) application. (c) 2023 Sharif University of Technology. All rights reserved.