Miniaturization and Bandwidth Enhancement of a CPW-Fed Annular Slot Antenna Using Ris

Abstract

Abstract-In this paper a CPW-fed annular slot antenna is miniaturized with enhanced impedance bandwidth using a reactive impedance surface (RIS) substrate. The RIS is realized by patterning 3 × 3 array of circular elements over an inexpensive FR-4 substrate which is backed by a circular metallic plane. Due to the compensation of electric and magnetic energy stored by antenna and RIS substrate respectively, the antenna resonance frequency is shifted by 53.6% compared with a simple annular slot antenna. By the inclusion of such reactive surface, input impedance of the antenna is reduced, and a remarkable improvement in impedance bandwidth from 11.66% to 64.26% is also noticed. Therefore, both miniaturization and bandwidth enhancement are achieved simultaneously with the present loading technique. The directivity of the RIS loaded antenna is increased further by loading a concentric metallic ring over the RIS loaded structure at a height above the RIS plane. The Ring & RIS loaded structure is fabricated for measurement purpose. A good agreement is obtained between the simulated and measured results for both RIS loaded and Ring & RIS loaded configurations. The ring loading over the RIS antenna provides improvement in directivity about 5 dB. The peak gain and bandwidth are measured at −1.03 dBi and 58.62%, respectively.

Design of Miniaturized Dual and Tri-Band Slot Antennas with Bandwidth Enhancement for Various Applications

“…Next, miniaturization and bandwidth enhancement of slot antennas have been reported in [4][5][6][7]. In [4], it has been investigated that proper combination of loop, slit, and strip can provide 48.01% miniaturization with 62.09% bandwidth enhancement.…”

“…In [4], it has been investigated that proper combination of loop, slit, and strip can provide 48.01% miniaturization with 62.09% bandwidth enhancement. In [5], it is investigated that 53.6% miniaturization with increased bandwidth and radiation efficiency of a CPW-fed annular slot antenna using RIS is described. Then, the inductive loading and parasitic coupling to achieve 44.0% miniaturization and 94.0% enhancement bandwidth slot antennas are presented in [6].…”

Miniaturized dual‐band slot antenna design for GPS, amateur radio and WLAN applications

“…Not only miniaturization but also enhancement of bandwidth are discussed in References . Bandwidth enhancement and miniaturization of slot antenna using folded structure, complementary and self‐complementary realizations are addressed in Reference .…”

“…In Reference , bandwidth improvement and miniaturization are implemented by loading slits, loops and metallic strips. Miniaturized ZOR antenna with increased bandwidth, miniaturized with increased bandwidth and radiation efficiency of a CPW‐fed annular slot antenna using RIS and miniaturized patch antenna with increased bandwidth which is based on signal‐interference feed have discussed in References respectively.…”

Circular slot antenna for triband application

“…The rings are made of a nonmagnetic metal like copper, and there is a little gap between them. It creates the proper magnetic susceptibility up to 200 terahertz [21]- [25].…”