Increasing bandwidth dual frequency triangular microstrip antenna feed by coplanar waveguide

The narrow bandwidth of microstrip antenna is one of the important features that restrict its wide usage. This paper presents a bandwidth enhancement technique using coplanar waveguide. A new design of coplanar waveguide feed line for dual frequency triangular microstrip antenna to increasing the bandwidth is proposed and experimentally studied. The two resonant frequencies can be generated by controlling the distance between the two slits. Return loss of -25.31 dB for the first resonant frequency 3.01 GHz and return loss of -23.51 dB for the second resonant frequency 3.96 GHz can be achieved at the slit height 12 mm when the distance between the two slits at 5 mm. The measured result show that the proposed antenna have the impedance bandwidth of 27.26% (VSWR < 2) and the two frequencies having the similar broadside radiation characteristics.