A V-Band 8 $,\times,$ 8 CMOS Butler Matrix MMIC

This paper presents a fully integrated V-band 8 x 8 Butler matrix in 0.13-μm CMOS technology. Since the number of building blocks exponentially increases with the order of the Butler matrix, the constituted components, including quadrature hybrids, phase shifters, and crossovers, must be redesigned for single-chip implementation in silicon. Design equations and novel layout arrangements are described. A demonstrated 8 x 8 Butler matrix was implemented, which has the compact chip size of 1.45 x 0.93 mm², no dc power consumption, and low average loss of 3.1 dB. Eight spatial beams with the averaged 5.9 dBi gain and 0.6^° main-beam direction tolerance were obtained in 56 to 66 GHz.