A Two Step Stair Shaped Dielectric Resonator Antenna with AMC for UWB Applications

This paper presents an ultra-wide band (UWB) antenna with two steps stair shaped dielectric resonator (SSDR) antenna. The two steps SSDR is placed precisely on the aperture to achieve an ultra-wide bandwidth of 136.2%. The first step of SSDR $(\text{DR}_{1}$ and $\text{DR}_{2})$ is fed directly by the microstrip line through aperture coupling technique whereas the second step $(\text{DR}_{3})$ is a parasitic DR placed adjacent to DR1. The SSDR is radiating with $\text{TE}{{}^{\mathrm{y}}}_{1\delta 1}$ -like mode at 5.32 GHz and $\text{TE}{{}^{\mathrm{x}}}_{\delta 11}$ -like mode at 6.3 GHz. The parasitic DR is improving the impedance matching and increasing the bandwidth by 11.3% due to the dielectric loading effect. Further a dual band artificial magnetic conductor (AMC) is placed below the UWB antenna to improve the antenna radiation characteristics. The improvement in average gain and gain variation is 36.7 % and 13.5% respectively. The antenna radiation efficiency is 81.6% with AMC reflectors.