A dual-band beam-switched slot array for GSM 900/1800MHz

A dual- and wide-band beam-switched slot antenna array for GSM 900/1800 is presented in this paper. The cavity-backed slot element is employed to achieve the wide bandwidth with good isolation and high gain. A prototype of the phased slot array is fabricated and tested in an anechoic chamber. The beam can be steered in the plusmn45deg azimuth range by a beam-forming network operating at two bands. The Butler matrix employing four hybrids is used to form four beams to be selected by a single-pole 4-throw (SP4T) switch under different states. The measured 10 dB return loss bandwidth is larger than 20% for 900 MHz band and 23% for 1800 MHz band. The measured peak gain is 16.5 dBi at 920 MHz, 15.2i dB at 1800 MHz, respectively.