Ultra-Wideband Air-Filled SIW Cavity-Backed Slot Antenna with Multipolarization Reconfiguration

Air-filled substrate integrated waveguide (AFSIW) cavity-backed slot antenna topologies are promising candidates to address the specific design challenges posed by the Internet of Things (IoT). In this contribution, we demonstrate a new single-feed ultrawideband cavity-backed slot antenna with multipolarization reconfiguration by leveraging four quartets of PIN diodes in substrate-independent AFSIW technology for operation in the [5.15-5.85] GHz frequency band. To achieve ultra-wideband performance, two concentric annular slots are created on the top of the circular cavity. By electrically shorting these annular slots at well-defined positions by the aforementioned PIN diodes, dynamic polarization reconfiguration is achieved by switching their DC bias current. Moreover, a systematic investigation of the different loss contributions and power consumption is performed. A physical explanation of the different effects is also provided. Finally, a fabricated prototype exhibits a measured impedance bandwidth of 1.6 GHz (or 29%), a total efficiency higher than 74%, and a gain higher than 5.2 dBi for all four states in free-space conditions.