A 2x2 Integrated Filter Antenna Array

This paper deals with a 2x2 Integrated Filter Antenna (IFA) array designed at 5.2 GHz. By incorporating the filtering action in the conventional antenna array, the need for an additional filter for suppressing the out-of-band signals has been avoided. In order to achieve this the last resonator of the filter has been replaced by a slot antenna, operating at the same band as that of the filter, in each arm of the array. The overall dimension of the subsystem has been optimized to 1.56 lambda(0) x 1.56 lambda(0). It has got a fractional bandwidth of 3.0% at 5.2 GHz. The sub-system provides a maximum gain of 12.43 dBi and HPBW of 33 degrees in broadside direction. The proposed structure was designed, simulated and fabricated. The measured reflection co-efficient plot shows a shift of 0.09 GHz of the overall band which may be due to the fabrication tolerances.