Radio frequency direction sensing enabled by broadside coupled split ring resonantors

Directional radio frequency (RF) sensing plays an essential role in various applications that concern localizing RF sources. However, current directional RF sensing technologies are hampered by their large antenna sizes and complex RF signal processing circuits, hindering the development of miniaturized subwavelength direction sensors. This paper presented a non-Hermitian broadside coupled split ring resonators (BC-SRRs), which can identify the direction of an incident RF signal with angles ranging from 0° to 180°. The non-Hermitian Hamiltonian of the system can be interpreted by the temporal coupled mode theory (TCMT). We further employed a one-stage Dickson voltage multiplier to rectify the RF signals and demonstrated directional RF sensing ability. Our results showcase the potential of the proposed technique using non-Hermitian BC?SRRs as a pathway towards subwavelength antenna-based RF direction finding.