Compact phased array antenna system based on dual-band operations

This article presents a novel approach to shrink the size of the conventional phased array antenna fed by Butler matrix. The proposed size reduction of the phased array antenna is obtained by designing the whole system to operate at dual frequency bands. Due to the dual-band operation, an N-element phased array antenna can be used to generate 2N radiation beams, leading to a great size reduction. To verify this design concept, a dual-band feed network is built based on a dual-band 4 x 4 Butler matrix. By integrating this dual-band feed network with a four-element antenna array, eight distinct radiation beams can be realized. An experimental prototype operating at 5 and 8 GHz is designed and fabricated. It can achieve the same function as the conventional phased array antenna system using single-band 8 x 8 Butler matrix, realizing a great size reduction. The simulated and measured results show good agreement with the design theory. (c) 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1391-1396, 2014