A Broadband Variable-Gain Amplifier and a Broadband Self-Calibrated High-Sensitivity Power Detector for the Square Kilometre Array
Date
2014-12-03
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Abstract
The Square Kilometre Array (SKA) is an international project to design and construct the
next generation ultra-sensitive radio telescope. Depending on the final configuration, the
SKA will require millions of receivers ideally fabricated in a low cost semiconductor process.
This thesis presents a study of using CMOS technologies, which are themost common
and less expensive semiconductor option, to implement a variable gain amplifier (VGA)
with a linear-in-dB performance and an RMS power detector (PD) for a mid-frequency
SKA receiver.
Two linear-in-dB VGAs were designed and experimentally verified in this work. The
first VGA meets most of the SKA specifications except bandwidth and linear-in-dB range.
The second VGA uses a bandwidth extension technique and a low threshold voltage transistor
to achieve a maximum tunable gain range of 34 dB and the linear-in-dB range of 28.5
dB within ±1 dB error, an upper 3 dB cutoff frequency of 2.1 GHz and a power consumption
of 1.1mW. Both S11 and S22 are less than -10 dB from 100 MHz up to 4.2 GHz. This
VGA achieved the lowest power consumption among comparable VGAs published to date.
A differential broadband self-calibrated RMS PD using the MOSFET square-law characteristics
was proposed and experimentally verified in this work. After automatically compensating
mismatches between all circuit components by adjusting input transistor bulk
voltage, the proposed PD circuit showed the highest sensitivity and lowest power consumption
of all PDs published prior to this work. The PD operates over an input power range
from -48 dBm to -11 dBm with output voltage offset less than 0.95 dB for the SKA midfrequency
range with an input-referred P1dB of -11 dBm, 3 dB bandwidth of 1.8 GHz and
power consumption of only 1.2 mW. This PD meets all requirements of the mid-frequency
SKA receiver. This power detector was embedded within the receiver and fabricated in
a TSMC 65nm CMOS process. Measurement results showed an input power range from
-40 dBm to -20 dBm with power consumption of 1.5mW.
Description
Keywords
Engineering--Electronics and Electrical
Citation
Wu, G. (2014). A Broadband Variable-Gain Amplifier and a Broadband Self-Calibrated High-Sensitivity Power Detector for the Square Kilometre Array (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/24637