CPW-fed circular disc monopole antenna with defected waveguide structure

This paper presented a parametric study on coplanar waveguide-fed (cpw-fed) circular disc monopole antenna with defected waveguide structure (dws). the cpw-fed circular disc monopole antenna was designed to cover wideband frequencies. afterward,the monopole antenna was attached to a waveguide with a uniplanar compact defected waveguide structure (uc dws). the simulation design and parametric studies were done by using the cst microwave studio software. initially,the cpw-fed circular disc monopole antenna was designed to achieve return loss of -10db from 2.36ghz to 10ghz. the directivity has improved significantly when the monopole antenna was attached to a waveguide where the highest directivity was 9.83dbi at 8.5ghz. however,narrower bandwidth and lower efficiency were achieved. it achieved a bandwidth of 0.49ghz and highest efficiency of - 1.76db at 8.5ghz. the uc dws was then designed on the inner surface of the waveguide with smaller dimension with 6.25 x 6.25mm2 and a small gap of 0.3mm. the directivity and gain have been improved. the highest directivity and gain were 7.10dbi at 8.5ghz and 5.42db at 6.5ghz respectively. the bandwidth was 3.66ghz where it covered from 6.34ghz to 10ghz.