Design of 60-GHz Circular-Polarization Antenna Array in Glass-IPD for Monostatic Radar MMICs

In this work, a 60-GHz $2\times 2$ circular-polarization (CP) antenna array is newly proposed for the applications of monostatic radar systems. Due to the nature of a reverse sense of rotation when the radar signal is backscattered from metal surfaces or biological objects, the proposed antenna array is designed to retain its reciprocity but with reverse polarization. The good isolation between TX/RX can be thus achieved without using the circulator in the system. This proposed antenna consists of a $2\times 2$ path antenna array and a feeding network. The circuit was implemented using glass-based integrated passive device (IPD) technology with chip size as $4.065\times 4.065\ \mathbf{mm}^{2}$. The results demonstrate that the high isolation of 42 dB can be achieved at 62.4 GHz. This work provides a feasible solution for radar MMICs.