Slits and Slots Loaded Dual Band Circularly Polarized Patch Antenna for WLAN/WiMAX Communications

In this paper, a pentagon shaped microstrip patch antenna with dual band circular polarized (CP) is proposed. The pentagon patch antenna is loaded with narrow rectangular slits to achieve dual band resonance with good impedance matching at 2.5GHz and 3.5GHz. The antenna is further modified by introducing of the slot structure on its patch radiator which gives CP at the two resonating frequencies. The antenna is compact with a layout area of 0.375λ × 0.375λ, for λ is the free space wavelength corresponding to the lower resonant frequency. The CP radiation patterns are investigated and found to be stable with satisfactory right hand circular polarization (RHCP) to left hand circular polarization (LHCP) isolation. The antenna has satisfactory gain of 3.4dB and 4.7dB at the lower and upper CP bands respectively which is suitable for practical wireless applications.