A Millimeter-Wave Power Amplifier and A Phase-Locked Loop for the W-Band Application
Date Issued
2011
Date
2011
Author(s)
Chang, Tao-Yao
Abstract
The W-band lies in the frequency bands from 75 to 110 GHz. This band is used for millimeter-wave radar research, satellite communications, military radar targeting and tracking applications. Especially, the frequency band from 76 to 77 GHz has been allocated for long range automotive radars in recent years. Owing to the severe specifications and requirements, many critical circuits in the automotive radar system are mainly fabricated by GaAs technologies. However, with the continuous advance of the CMOS process, the automotive radar can be realized by the CMOS technology to demonstrate the possibility of the low cost transceiver implementation. Nonetheless, the CMOS technology possesses some inherent drawbacks, which are the low supply voltage, the low breakdown voltage, the low gain and the large loss of on-chip passive components, so it is difficult to realize the high performance CMOS circuits for the automotive radar application. This thesis presents the circuit techniques to alleviate those bottlenecks and also provide the experimental results to verify the functionality.
In Chapter 2, the short stub topology and the transformer-based power combiner are employed by the 77 GHz power amplifier to reduce the signal loss and improve the output saturation power respectively. The measured results reveal that this power amplifier achieves a small signal gain of 9.9 dB, a 1 dB compressed output power of 11.2 dBm, a peak power-added efficiency of 10.4% and a saturated output power of 13.2 dBm at 77 GHz under a 1.2 V supply. This work has demonstrated that CMOS technology is suitable for the power amplifier at high output power application such as 77 GHz automotive radar system.
Chapter 3 deals with the proposed wide-locking range divide-by-three injection locked frequency divider. This divider is realized in general purpose 65nm CMOS technology. The proposed divider employs the direct multiple-injection technique to enhance the locking range, which solves the narrow locking range problem among conventional divide-by-three injection locked frequency divider. The circuit has a measured locking range from 75.9 to 85.3 GHz without tuning mechanism, while only drawing 2.8 mA from a 1 V supply.
In Chapter 4, the low power W-band PLL is presented. This PLL is composed of the proposed divide-by-three frequency divider, which is mentioned in Chapter 3, and the VCO which adopts the distributed-LC tank to mitigate the effect of the low Q factor of varactors and to drive the heavy loading without buffers under the same oscillation frequency. This PLL only dissipates 17 mW excluding testing buffers. Thus this PLL reveals the low power CMOS millimeter-wave clock generator can be achieved by virtue of the high division frequency divider and the proper divider selection.
Subjects
Millimeter-Wave
Power Amplifier
Phase-Locked Loop
W-Band
Type
thesis
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