This paper presents the design of a wideband X-band microstrip 4×4Butler matrix. The wideband performance of the Butler matrix means that it possesses equal coupling and difference of phases throughout the operating band. Design of the wideband components such as 3-branch branch line hybrid, crossover and Schiffman line phase shifter are presented in this paper. A final design of the Butler matrix is proposed. The Butler matrix exhibits couplings and phase errors within −6.7 ± 0.7 dB and 10◦ over a 20% bandwidth with a center frequency at 10 GHz.
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