A novel printed slot array antenna with omnidirectional pattern

A novel printed slot array antenna with omnidirectional radiation pattern in the horizontal plane is proposed. It uses rectangular shaped loop slots as the radiators, which are etched on two parallel ground planes of a 50Ω stripline. A proposed antenna with 8 back-to-back radiators is optimized making used of the parallel Genetic Algorithm (GA) on a cluster system. A prototype antenna was fabricated and measured. The measurement results compare well with the simulation data, and show this antenna obtains encouraging features, e.g. well-formed omni-directional pattern with gain variations less than 0.3 dB, a high gain level of over 9.5dBi, side lobes of 12.dB below the main lobe, no beam squint and a return loss of -16.4dB at its working frequency of 5.8GHz, as well as an impedance bandwidth of 6.2% for S11<;-10dB.