Gain enhancement of Four Edges Gap-coupled Microstrip Antenna using I-shaped resonators as superstrate

In this paper, an array of 7 × 7 I - shaped resonators is used as Near-zero Index Metamaterial (NZIM) superstrate over Four Edges Gap-coupled Microstrip Antenna (FEGCOMA) for the purpose of gain enhancement. Prototypes of FEGCOMA and NZIM superstrate are fabricated to validate the results obtained in simulation. Measured results confirm that the FEGCOMA with the NZIM superstrate operates in S-band with a bandwidth is 16.06% centered at 2.49 GHz and exhibits a gain of 4.55 dBi to 6.75 dBi in the operating range, which is around 2 dBi more than the average gain of reference FEGCOMA.