The allocation of frequency spectrum by the FCC for Ultra Wideband (UWB)
communications in the 3.1-10.6 GHz has paved the path for very high data rate Gb/s
wireless communications. Frequency synthesis in these communication systems involves
great challenges such as high frequency and wideband operation in addition to stringent
requirements on frequency hopping time and coexistence with other wireless standards.
This research proposes frequency generation schemes for such radio systems and their
integrated implementations in silicon based technologies. Special emphasis is placed on
efficient frequency planning and other system level considerations for building compact
and practical systems for carrier frequency generation in an integrated UWB radio.
This work proposes a frequency band plan for multiband OFDM based UWB
radios in the 3.1-10.6 GHz range. Based on this frequency plan, two 11-band frequency
synthesizers are designed, implemented and tested making them one of the first
frequency synthesizers for UWB covering 78% of the licensed spectrum. The circuits are
implemented in 0.25µm SiGe BiCMOS and the architectures are based on a single VCO at a fixed frequency followed by an array of dividers, multiplexers and single sideband
(SSB) mixers to generate the 11 required bands in quadrature with fast hopping in much
less than 9.5 ns. One of the synthesizers is integrated and tested as part of a 3-10 GHz
packaged receiver. It draws 80 mA current from a 2.5 V supply and occupies an area of
2.25 mm2.
Finally, an architecture for a UWB synthesizer is proposed that is based on a
single multiband quadrature VCO, a programmable integer divider with 50% duty cycle
and a single sideband mixer. A frequency band plan is proposed that greatly relaxes the
tuning range requirement of the multiband VCO and leads to a very digitally intensive
architecture for wideband frequency synthesis suitable for implementation in deep
submicron CMOS processes. A design in 130nm CMOS occupies less than 1 mm2 while
consuming 90 mW. This architecture provides an efficient solution in terms of area and
power consumption with very low complexity.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2500 |
| Date | 15 May 2009 |
| Creators | Mishra, Chinmaya |
| Contributors | S?hez-Sinencio, Edgar |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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