Microstrip Antennas for Indoor Wireless Dynamic Environments

Design of passive RF beam forming network for wireless LAN application

“…Schiff man line phase shifter is a wideband differential phase shifter, which changes the phase shift slope of one transmission line using the coupled line to match that of the other transmission line. To our knowledge, there are two literatures in which coupled line was used in the phase shifter of Butler matrix, i.e., the wideband Butler matrix in strip line [9,11], in which the Schiff man line phase shifter was also used to construct 180• hybrid; and the dual-band Butler matrix [10], in which a pair of coupled lines was used to fit the phase shift character of dual-band. In this paper, wideband components such as 3 dB hybrid coupler, cross-coupler, and line phase shifter are designed and used to construct a microstrip Butler matrix with a bandwidth of 20% and with a centre frequency at 2.440 GHz.…”