A $V$ -Band Switched Beam-Forming Antenna Module Using Absorptive Switch Integrated With 4$\,\times\,$ 4 Butler Matrix in 0.13- $\mu{\hbox {m}}$ CMOS

A beam-forming antenna module is demonstrated using an integrated CMOS beam-former chip and a simple two-metal layer printed circuit board at
$V$
-band. The beam-former circuit integrates an absorptive single-pole four-throw switch together with a 4
$\,\times\,$
4 Butler matrix using a 0.13-
$\mu{\hbox {m}}$
CMOS process. The entire insertion loss of the integrated beam former integrated circuit (IC) is around 7.5 dB at 60 GHz, among which 3 dB is attributed to the Butler matrix. The overall phase error is within
${\pm}$
12%. The antenna module employs backside radiation structure using series-fed patch antenna arrays to suppress parasitic radiation. The measured radiation pattern shows good agreement with the simulation. To the best of our knowledge, this is the first demonstration of the beam-forming antenna module using a single-chip CMOS switched beam-former IC at
$V$
-band