Abstract-This article presents the coplanar capacitive coupled probe fed microstrip antennas for dual frequency band operation. The proposed antenna is excited by a single probe feed connected to a capacitive strip. Of the two dual band antennas presented here, the first one uses small air gap and the other is designed without air gap. In the first case an effort has been made to reduce the height of suspended antenna. A vertical slot is placed to obtain antenna resonance at low frequency side, and also for proper impedance matching. After presenting the basic geometry the second configuration (which uses no air gap) which also offers dual band operation at the expense of reduced bandwidth is presented. Measured values fairly agree with the simulated results.

In this paper we present a suspended rectangular and circular patch circularly polarized (CP) microstrip antenna with coplanar capacitive feed. Of the two circularly polarized (CP) antennas presented here, the first antenna uses fractal geometry with center slot within the rectangular patch and other having two perpendicular slots etched on circular patch in order to get circular polarization. The first antenna has an axial ratio bandwidth « 3dB) of 7.1% and a much higher impedance bandwidth of about 49% (SlI<-10 dB) and also yields return loss better than -15dB in the useful range of circular polarization.After presenting the first geometry we proposed the second geometry (circular patch) which has simple geometry as compared to first geometry (fractal rectangular patch), which also offers circular polarization, with axial ratio bandwidth (AR < 3dB) of 7.85% and also the geometry having high impedance bandwidth similar to first geometry of 53% (SlI<-lO dB) and SlI is well below -20 dB in range of CP operation. Measured values fairly agree with the simulated results.