CMOS Microwave Vector Signal Processing Components and Applications
Date Issued
2011
Date
2011
Author(s)
Wang, Chao-Wei
Abstract
This dissertation focuses on the analysis and design of the CMOS microwave vector signal processing components, including the phase shifter, the phase-invertible variable attenuator (PIVA), and the variable delay line. The proposed CMOS vector-sum based phase shifter consists of one 3-dB directional coupler, two identical PIVAs, and one Wilkinson power combiner. All building blocks are realized by using the synthetic transmission lines for circuit miniaturization. The theoretical analyses confirm the effects of the non-ideal PIVA on the increasing of the root-mean-square (RMS) phase error and magnitude variation of the phase shifter. The design procedures, which can eliminate the effects from the voltage-dependent parasitics of the reflection load and the non-ideal directional coupler, are reported to make an ideal phase reversal and reduce the attenuation-dependent phase shifting of the PIVA. The comparisons between simulated and experimental results show that the proposed design can cover full 360 degree phase shifting with less than 2.5degree of RMS phase error and 0.45 dB of magnitude variation from 20 to 28 GHz. Meanwhile, the proposed CMOS vector-sum based phase shifter has a flat group-delay deviation of 6.7 ps at K-band. The experimental results show the proposed phase shifter has precise phase control and good phase linearity.
On the other hand, a refection-type variable delay line (VDL) is realized in standard CMOS technology. It consists of one directional coupler and two identical reflection loads. The theoretical derivations show that the reflection load in the parallel form can make the reflection-type VDL achieve wider tuning range of the group delay than that of the reflection load in the series form. The proposed variable delay line has a tuning range of the group delay higher than 87 ps in K-band. Furthermore, to compensate the loss of the reflection load, the cross-coupled pair is adopted to eliminate the resistive parasitics of the reflection load. It has a group-delay tuning range of 196.2 ps and insertion loss of 1.25 dB at 24 GHz.
Meanwhile, two CMOS amplifier designs are presented in this dissertation. The experimental result shows that the deviation of the group delay of the proposed amplifier is less than 5 ps from 22 to 26 GHz. Another amplifier with high reverse isolation design has forward transmission gain and reverse isolation of 12.5 and 37.2 dB at 24 GHz, respectively. Furthermore, the proposed synthetic transmission lines with dummy fills are adopted in the amplifier design. The experimental results show a few effects on the electrical characteristics of the amplifier, revealing the feasibility for system integration.
Finally, the monolithic integrated microwave systems incorporating the proposed phase shifter, PIVA, amplifier with flat group delay response are implemented in the standard CMOS technologies, including the four-element beamformer, the active quasi-circulators with narrow- and wide-band leakage suppression. The proposed beamformer is realized in standard 0.13-um CMOS technology with a chip size of 1980 um × 2000 um. The forward transmission gain and input P1dB of the proposed beamformer are 6.7 dB and -19.8 dBm, respectively. It has a phase shifting range of 360degree, a magnitude controlled range of 20 dB, and a group-delay deviation of 22.8 ps. The experimental results show the proposed beamformer has good pattern synthesizing capability and high linearity.
The proposed CMOS active quasi-circulator incorporating feedforward technique has dual transmission gains in the transmitting and receiving paths with the leakage suppression of 44.7 dB at 23.63 GHz. Furthermore, to extend the bandwidth of the leakage suppression, the strategies of the proposed design are following. The first is equalized the group delays of leakage and feed-forward path. The second is reduced the group delay deviation of magnitude/phase controlled unit during magnitude and phase adjustment. The proposed K-band active quasi-circulator with wideband leakage suppression is realized in the standard CMOS 0.13-um 1P8M technology. From 22 to 26 GHz, the leakage suppression from transmitter to receiver is larger than 30 dB.
Subjects
Microwave vector signal processing component
Phase shifter
Variable attenuator
Variable delay line
Beamformer
Active quasi-circulator
Type
thesis
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