Gain enhancement of slot antenna using zero-index metamaterial superstrate

Abstract

This article presents a technique to enhance the broadside gain of a CPW fed slot antenna using a single layer metamaterial (MTM) superstrate. A finite array of 3× 3 ring unit cell has been designed on both sides of a dielectric substrate to form the MTM superstrate. The gain enhancement is obtained using the zero‐index property of the metamaterial. The broadside gain enhancement for the proposed antenna is 7.4 dB more in comparison to that of the reference slot antenna. The proposed MTM superstrate loaded antenna provides a minimum overall thickness in the context of using ZIM superstrate for gain enhancement of antennas reported in earlier literatures. The overall thickness of the MTM loaded antenna is 0.13λ0, where λ0 is the free‐space wavelength at the resonance frequency of the antenna. Also, a high efficiency of about 93.2% is obtained in this case. The loading of the MTM superstrate produces a minimal effect on the cross polarization performance of the proposed slot antenna.

Application of metamaterials for performance enhancement of planar antennas: A review

“…This problem even becomes more severe for a multiband antenna especially in lower frequency bands . In this regard, however, metamaterial antennas become the alternative candidates for different communication bands to improve antenna performance characteristics by using metamaterial units as a load on/near the patch, loading/etching from the ground plane, integrating inside the substrate, or making them as superstrate …”

“…A patch antenna with a single and double near‐zero refractive index modified Jerusalem cross‐unit cell metamaterial superstrate has been presented in Reference to achieve 5.1 and 7 dB gain improvement. A slot antenna with a 3 × 3 array of zero refractive index closed ring metamaterial unit cells loaded on both sides of a single layer superstrate has been presented by Reference and realized a 7.4 dB gain increment. Larger size arrays of unit cells were tested but a gradual degradation of gain was noted owing to the less effectiveness of the slot antenna to illuminate the superstrate structure.…”

Performance improvement of slotted elliptical patch antenna using FSS superstrate

“…Also the lateral antenna and unit dimensions in Refs. [21][22][23][24][25] are quite larger at their resonance frequency. In Ref.…”

“…Among those, single layer ZIMs proposed in Refs. have the ability to control the direction of radiation. However, the unit cell dimensions of these materials in Refs.…”

“…There are various structures have been reported by many authors as a superstrate in the context of gain enhancement. [17][18][19][20][21][22][23][24][25][26] Among those, single layer ZIMs proposed in Refs. 17-21 have the ability to control the direction of radiation.…”