Asymmetric Coplanar Strip‑Fed multiband loop antenna with FSS cover for gain improvement

Abstract

Asymmetric Coplanar Strip (ACS)-Fed with loop resonators is fashioned in the form of nested configuration, which imparts multiband radiation. By forming nested loops, it increases the number resonance substantially. An invented antenna possesses five rectangular loops, which induces the antenna to radiate 1.17 GHz, 1.74 GHz, 2.31 GHz, 2.93 GHz, 3.63 GHz and 5 GHz frequencies. The developed antenna is amalgamated by ACS-fed with loop resonators, it has been fabricated on a FR-4 substrate having the size of 18$\times$18$\times$1.6 mm³, ${\epsilon }_r$= 4^.4 and $\tan \delta$ = 0.02. To ascertain the optimal peak gain of the antenna, Frequency Selective Surface (FSS) amelioration approach has been carried out. It is fashioned on 44.5$\times$44.5$\times$0.8 mm³ FR-4 substrate by 4$\times$4 FSS array configurations. At 5 GHz resonance, the antenna imparts the peak gain of 0.52 dBi without FSS. To meliorate the peak gain, the antenna is covered by 4$\times$4 FSS array, which executes as the reflector for rendering the peak gain of 6.62 dBi. The transmission line model of FSS unit cell has been explored with the help of LC values to identity the band reject mechanisms, which is examined by Agilent ADS software. The calibrated radiation factors of the fabricated antenna with FSS cover endorse simulated counterparts, which is suitable for GSM, WiMAX and WLAN applications.