A pattern-diversity antenna module for dual-band WLAN systems

The main idea of the antenna diversity is using multiple switched antennas to provide the separate propagation channels. The technique mitigating the effect of the short-term fades is the switchable radiation pattern in which the signals received over channels are combined properly to increase the probability, and power intensity of the received signal. In this paper, a microstrip antenna module with switchable radiation patterns has been fabricated and measured. The antenna module includes a power divider, a switch module and a two-element Z-like slot antenna array. The wideband Wilkinson power divider is integrated with the dual-band single-port-double-throw(SPDT) switch module to provide two individual signal paths for the inputs of the two-element antenna array. By changing the bias voltages of the FET devices, the radiation patterns of the antenna array are changed and switched. Hence, switching radiation patterns are demonstrated such that the fading effect due to the multipath propagation can be avoided.