Planar Array Antenna with Radiation Pattern Reconfigurability Using PIN Diode

Modern data communication, such as wireless technology with IEEE 802.11 b/g/n standard, demands its antenna to have ability to conform to the changing environment. In this paper, such antenna with the ability of radiation pattern reconfiguration is proposed. The antenna which is configured in a planar array is designed on 2 layers of FR4 epoxy dielectric substrate. On top side of the first layer, 8 square patch antennas workable at the frequency of 2.4 GHz are circularly configured and fed using a microstrip feeding line based on proximity coupling technique. The microstrip feeding line is printed on top side of the second layer, while the groundplane which takes a circular shape is placed on bottom side of the second layer. PIN diodes with the type of SMP1345-079LF are connected at the end of microstrip feeding lines to modify the radiation pattern of array antenna. When 2 antennas positioned across each other are set to be active, the measured reflection coefficient is –14.39 dB at frequency of 2.4 GHz. In addition, the antenna has and the measured gain of 0.25 dBi and –10 dB working bandwidth of 240 MHz ranges from the frequency of 2.32 GHz to 2.56 GHz.