Bandwidth and gain enhancement of optically transparent 60-GHz CPW-fed antenna by using BSIS-UC-EBG structure

Abstract A method in terms of bandwidth and gain enhancement is presented for optically transparent coplanar waveguide fed (CPW-Fed) antenna, which supports unlicensed 60 GHz band (57–66 GHz) applications. The original antenna and mesh antenna in [8] were designed on a transparent material that is made of a 0.2-mm-thick fused silica 7980 Corning substrate ( ɛ r : 3.8 and tan δ : 0.0001). However, the peak gains of −5.3 and −5.4 dBi at 60 GHz of those antennas can be further improved. Thus, in this paper, a novel bidirectional symmetric I-shaped slot uniplanar compact electromagnetic band-gap (BSIS-UC-EBG) structure with a reflection phase band of 58.0–62.1 GHz is proposed to improve antenna performance. Based on this BSIS-UC-EBG structure, both transparent BSIS-UC-EBG antenna and transparent mesh BSIS-UC-EBG antenna with enhanced properties are presented and discussed. The analysis results show that the impedance bandwidth (the peak gain) of transparent BSIS-UC-EBG antenna and transparent mesh BSIS-UC-EBG antenna are enhanced to 36.6% (4.7 dBi) and 44.7% (5.8 dBi), respectively. In addition, we also discuss the comparison of radiation patterns at 60 GHz, and the results illustrate that the radiation patterns are basically identical.