This article presents ultra-wideband (UWB) rectangular microstrip antennas centered at 6GHz. For obtaining UWB, enhancement gain, a double layer microstrip antenna is proposed. The lower layer was etched by rectangular microstrip patch and two slots cutting in the metal ground plane. The patch acts as exciter and the slots as a radiator, and second layer as a cavity back. Impedance matching bandwidth achieved by tuning the length, width of slot, patches length, thickness of foam layer and tapered transmission length. The simulated result indicates good performance antennas, since it's achieved up to 89% bandwidth (active VSWR < 2), high efficiency up to 0.9, and enhancement realized gain up to 9dB.
Index Term: UWB, Rectangular Patch, Slots, Cavity back, Reflection coefficient S11, and Gain