A Tri-Functional Multiplexed Linear Array with Simultaneous Transmitting, Receiving, and Backscattering Control for IoT Applications

The massive number of wirelessly connected devices interacting in the increasingly crowded Internet of Things (IoT) environment places high demands on electromagnetic (EM) wave manipulation in a compact size. Since the limits of the reciprocity theorem, it remains challenging to independently achieve the transmitting, receiving, and scattering field control on the same array in the in-band co-polarization scenarios. To address this challenge, this paper presents a novel tri-functional multiplexed linear array (TMLA), which can multiplex the transmitting, receiving, and backscattering control functions within a single array. Firstly, a co-linearly polarized dual-port linear antenna array (CDLA) with joint in-unit and inter-unit decoupling is proposed, where isolation between all ports enables the independent implementation and design of radiation and scattering; secondly, a feeding network based on the self-interference cancellation (SIC) technique is designed to realize transmit-receive (Tx-Rx) isolation; thirdly, an active scattering control circuit is designed to achieve enhanced scattering control capabilities, including flexible enhancement or reduction of backscattering. A prototype is fabricated and measured. Measured results show that the proposed array achieves multifunction multiplexing with well-isolated transmitting, receiving, and scattering ports. The proposed array can be applied to IoT scenarios, especially in intelligent transportation systems.