Highly-isolated compact self-diplexing antenna

Abstract

This article introduces a novel low-profile self-duplexing antenna with high isolation for out-band operation applications. The antenna design features two patches, one rectangular and one triangular, both utilizing the quarter-mode substrate integrated waveguide (QMSIW) cavity for enhanced performance. Furthermore, miniaturization is achieved through the incorporation of capacitive slots. The resulting self-duplexing antenna is engineered for operation at both 5.8 and 9.8 GHz frequencies, with an impressive alignment between measured and simulated results. Notably, the antenna’s dimensions are remarkably compact, occupying only 0.08 λg2, while still delivering a remarkable 40 dB isolation between its two ports. Furthermore, the antenna maintains consistent radiation patterns at both frequencies. Simulated gains at 5.8 and 9.8 GHz are 4.1 and 4.6 dBi, respectively, enhancing its suitability for dual-band wireless communications. An additional advantage of this design is its independent tuning of frequency bands, facilitated by adjusting the size of the capacitive slots. The article also delves into the investigation of the tuning circuit model for the self-diplexing antenna, which is crucial in the design process. This model elaborates on how the antenna operates and how the frequency bands can be regulated, providing valuable insights into its functionality and versatility. Moreover, the proposed antenna stands out as the most compact self-duplexing antenna with the highest level of isolation when compared to existing literature, making it a valuable asset for dual-band wireless communication applications.