| dc.description.abstract | The low phase noise VCO is necessary in the modern communications systems, especially for the high-level digital modulation schemes, such as n-QAM and n-PSK modulation. Therefore, a low phase noise VCO is essential for the applications.
The goal of the thesis is to design and implement low phase noise VCOs using GaAs HBT and CMOS technologies. The thesis was organized into three parts. An introduction was first summary to present the design and implement of the oscillators, and a Ku-band VCO is demonstrated in this part. The principle and advantages of the π-feedback oscillator is described, and the balanced π-feedback VCO is implemented by using 2-μm HBT process. Finally, the basics and application of the quadrature
VCO with a reflection-type IQ modulator is presented and then the quadrature VCO
with a reflection-type IQ modulator is implemented using a 0.18-μmCMOS process.
The Ku-band VCO is designed and implemented using WIN Semiconductors
2-μmGaAs HBT technology. The frequency is from 14.6 to 16.6 GHz with a phase
noise of -112.5 dBc/Hz. Besides, the VCO can provide a maximum output power of
6.9 dBm under core current of 12.5 mA from a 2 V supply. This VCO has the
advantages of a low phase noise and wide tuning range.
In addition, the Q-band VCO using balanced π-feedback is demonstrated in this
thesis. With a core power consumption of 20 mW, the tuning range is from 41.2 to
42.1 GHz. The measured phase noise is -105.5 dBc/Hz at 1-MHz offset. This circuithas the advantages of low phase noise and low power consumption.
Finally, the QVCO with a reflection-type IQ modulator using standard 0.18-mm
bulk CMOS technology is presented. A serial-coupled QVCO and a reflection-type IQ
modulator are combined in a single chip. The advantage of this configuration is easy
evaluation of the amplitude and phase errors of the QVCO. The circuit achieves the
tuning range of 1 GHz and the phase noise of -115 dBc/Hz at 1-MHz. The total power
consumption is 5.1 mW with a dc supply voltage of 1.7 V. Moreover, the amplitude
and phase errors of the QVCO are with in 0.5 dB and 3°, respectively. The QVCO
with a reflection-type IQ modulator has the advantages of low phase noise, low power
consumption and the lowest FOM. | en_US |