Near field analysis of RDRA loaded with split ring resonators superstrate

In this article, split ring resonator (SRR)-based electromagnetic band gap (EBG) structure is utilized in the near field region of rectangular dielectric resonator antenna (RDRA) to enhance its gain. The investigation is carried out by designing RDRA and SRR EBG, followed by integration of RDRA with SRR as superstrate. RDRA is coaxially fed at offset along Y-axis to provide fractional bandwidth (BW) of 35.5%. EBG is designed by adopting SRR as unit cell to provide band gap from 3 to 5.85 GHz covering the entire BW of RDRA which is also confirmed by the lumped model extraction of SRR. An array of 5 x 5 unit cells is used as a superstrate above the RDRA. Coupling of SRRs with RDRA in the near field region effectively cancels the transverse fields because of oppositely induced currents in the 2 rings. This helps in improving the radiation characteristics of the RDRA which results in improving the gain of the antenna.