Ultra-Compact SIRC-Based Self-Triplexing Antenna with High Isolation

Rusan Kumar Barik; Sławomir Kozieł

doi:10.3390/electronics12092112

Ultra-Compact SIRC-Based Self-Triplexing Antenna with High Isolation

Abstract

An ultra-compact self-triplexing antenna realized on a substrate-integrated rectangular cavity (SIRC) is discussed in this study. The proposed structure employs two L-shaped slots and an in-verted U-shaped slot to radiate at three independent operating frequency bands. Three 50-ohm microstrip feed lines are used to excite the radiation in these slots. The operating frequency is individually tuned using the slot size. The slot placement and size are designed having in mind obtaining one or more frequency bands below the SIRC cutoff frequency, which has the ad-vantage of enabling ultra-compact size. High port isolations are achieved by applying one of the ports orthogonally to the two remaining ones, which creates a weak cross-coupling channel. A lumped-circuit model is created to examine the antenna operation. The presented design has been prototyped and experimentally validated with the measured operating frequencies of 1.92 GHz, 4.43 GHz, and 5.25 GHz for GSM, 5G, and WLAN applications, respectively. The port isola-tions are better than 32.4 dB according to both EM simulations and measurements. Meanwhile, the measured realized gain of the antenna is better than 4.3 dBi at all bands.