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Integrated RF CMOS Frequency Synthesizers and Oscillators for Wireless Applications
Degree Doctor of Philosophy, Ohio State University, Electrical Engineering, 2004.
Abstract PLL (Phase-Locked Loop) frequency synthesizers are used in wireless transceivers for frequency conversion. Recent directions in PLL frequency synthesizer research and development are to fully integrate PLL synthesizers in CMOS technology, to improve phase noise performance, and to operate wide range of frequency bands and channel bandwidths. Fully integration of synthesizers in CMOS technology is desired for low cost, low power consumption and small size in mobile wireless terminals. Low phase noise is required by digital modulation techniques which have been used in new mobile standards for the efficient use of the frequency spectrum. Operation over a wide range of frequency bands and channel bandwidths are required to support migration and backward compatibility in the wireless standard evolution. This work investigates the PLL frequency synthesizer design and implementation in CMOS technology with focus on integration of wideband VCOs (Voltage-Controlled Oscillators). Phase noise of a PLL synthesizer is a major design parameter. A PLL noise model is developed for noise optimization purposes. Wideband RF VCO design with sub-bands is investigated. Frequency planning, synthesizer architecture and technology considerations are also explored for wideband VCO design. Band switching techniques VCO tuning range presented. Active VCO circuit topologies and resonator design are also presented. The PLL frequency synthesizers are designed and implemented for a multi-band/standard(IEEE 802.11a/b/g) WLAN radio in 0.18um CMOS. Phase noise trade-offs for PLL design are explored in this application. Development and design of a wideband VCO for this application is also presented. An auto calibration circuit is developed for VCO tuning band selection. Another application of the wideband PLL frequency synthesizer is designed and implemented for a fully integrated dual-mode frequency synthesizer for GSM and WCDMA standards in 0.5um CMOS. A hybrid integer-N/fractional-N architecture is developed to meet the multi-standard requirements. Design and implementation of high performance RF VCO depends on the RF models of the devices. RF CMOS characterization and modeling techniques are explored. Microwave wafer measurement and calibration techniques are also investigated for CMOS technology.
Advisor Mohammed ElNaggar |
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