Low-Loss Analog and Digital Reflection-Type

JasonYoo

Low-Loss Analog and Digital Reflection-Type [复制链接]

Abstract—Broad-band analog and digital reflection-type phase
shifters (RTPSs), showing constant phase shift over 1 : 3 bandwidth,
have been developed using microelectromechanical systems
(MEMS) technology. Two-unit RTPSs centered at two different
frequencies have been cascaded to achieve flat phase responses
over a wide frequency band. Each phase shifter uses air-gap
overlay coplanar-waveguide couplers for low-loss 3-dB coupling
and bridge-type MEMS capacitors for reflective terminations.
The fabricated analog phase shifter shows the average insertion
loss of 3.5 dB, and maximum phase error of 4.9 from 15 to
45 GHz. The 2-bit digital RTPS shows reduced maximum phase
error of 2.8 together with a comparable insertion loss of 3.1 dB
from 5 to 15 GHz. The details of the circuit design, analysis, and
fabrication procedures are presented together with the measurement
results. Compared with the similar constant phase shifters
using semiconductor diodes and transistors, the micromachined
RTPS of this study shows superior performance in terms of phase
errors, insertion losses, and bandwidth.