A Miniaturized Dual-Band Base Station Array Antenna Using Band Notch Dipole Antenna Elements and AMC Reflectors

A novel miniaturized dual-band dipole array antenna consisting of two parallel $1 \times 4$ subarrays for use in base stations operating in the digital cellular system (DCS) and wideband code division multiple access (WCDMA) bands is presented. Size miniaturization is realized by utilizing band notch dipoles (BNDs) as array elements and artificial magnetic conductors as reflectors for reductions in width and profile height of the array antenna, respectively. Using the BNDs of high radiation suppression at desired notch frequencies, the radiation from DCS subarray is suppressed in the WCDMA band and vice versa. High isolation between the subarrays, therefore, is achieved while reducing the subarray separation. In addition, a dual four-way unequal power divider is designed for beam pattern synthesis. The measured results show that realized gains of 12.1-12.6 and 12.4-13.1 dBi, respectively, within the DCS and WCDMA bands, as well as the first null depth and sidelobe level, respectively, of lower than -20 and -16 dB, are achieved simultaneously, indicating that the proposed array antenna is suitable for potential base station applications.