New Pattern Reconfigurable Circular Disk Antenna Using Two PIN Diodes for WiMax/WiFi (IEEE 802.11a) Applications

Reconfigurable radiation pattern shaping by means of circular disc planer antenna with a slot ring is presented. The proposed microstrip antenna has an overall dimension of 70x70mm(2) designed on a substrate of a dielectric constant 4.3. The designed antenna operates at 5.35 GHz with a central coaxial probe feed. By altering the configuration of two PIN diodes switches, the designed antenna has three different beam patterns in the yz plane. Biasing each diode separately result in about 60 degrees change in the main radiation pattern steering angle, while the frequency response are largely maintained. At resonance, the peak gains are approximately 3.5 dB, 4 dB and 4.3 dB, in the three configurations of the diodes. Return losses, peak gains and reconfigurable radiation patterns are reported, which are in very good agreement for WiMax/WiFi (IEEE 802.11a) applications.