Unidirectional Frequency Reconfigurable Bow-Tie Antenna Array with AMC Reflector

A unidirectional frequency reconfigurable bowtie antenna array (FRBAA) is presented. The array employs four doubled-sided bow-tie antennas as the radiating elements. By controlling the states of the PIN diodes mounted on the radiators, three switchable operating bands can be achieved. In order to produce unidirectional radiation patterns with low profile and good impedance matching in all the bands, a triband artificial magnetic conductor (AMC) is designed and incorporated with the array. The distance between the array layer to the AMC reflector is only 0.032 lambda(0) at the lowest operating frequency (2.4 GHz). The integration of the AMC not only yields good front-to-back ratios, but also improves the forward gains in all the operating bands.