Future generation of wireless systems will feature high data rates and be implemented in low voltage CMOS technologies. Direct conversion receivers (DCRs) will be used in such systems which will require low voltage RF front-ends with adequate linearity. The down-converter in a DCR is a critical block in determining linearity. In addition to detailed DCR modeling in MATLAB, this thesis, completed in 2005, deals with the design and characterization of a 1V, 8GHz quadrature down-converter. It consists of two mixers and a quadrature generator implemented in a 0.18m CMOS technology. The mixer architecture proposed in this work uses a new trans-conductor. It simultaneously satisfies the low voltage and high linearity requirements. It also relaxes the inherent trade-off between gain and linearity governing CMOS active mixers. The implemented mixer occupies an area of 320 x 400 m2 and exhibits a power conversion gain of +6.5dB, a P-1dB of -5.5dBm, an IIP3 of +3.5dBm, an IIP2 of better than +48dBm, a noise figure of 11.5dB, an LO to RF isolation of 60dB at 8GHz and consumes 6.9mW of power from a 1V supply. The proposed quadrature generator circuit features a new architecture which embeds the quadrature generation scheme into the LO-buffer using active inductors. The circuit offers easy tune-ability for process, supply and temperature variations by relaxing the coupling between amplitude and phase tuning of the outputs. The implemented circuit occupies an area of 150 x 90m2 and exhibits an amplitude and quadrature phase accuracy of 1 dB and 1.5° respectively over a bandwidth of 100 MHz with a power consumption of 12mW from a 1V supply including the LO-buffer. The quadrature down-converter features an image rejection ratio of better than 40 dB and satisfies the potential target specifications of future mobile phones, extracted in this work.

Future generation of wireless systems will feature high data rates and be implemented in low voltage CMOS technologies. Direct conversion receivers (DCRs) will be used in such systems which will require low voltage RF front-ends with adequate linearity. The down-converter in a DCR is a critical block in determining linearity. In addition to detailed DCR modeling in MATLAB, this thesis, completed in 2005, deals with the design and characterization of a 1V, 8GHz quadrature down-converter. It consists of two mixers and a quadrature generator implemented in a 0.18m CMOS technology. The mixer architecture proposed in this work uses a new trans-conductor. It simultaneously satisfies the low voltage and high linearity requirements. It also relaxes the inherent trade-off between gain and linearity governing CMOS active mixers. The implemented mixer occupies an area of 320 x 400 m2 and exhibits a power conversion gain of +6.5dB, a P-1dB of -5.5dBm, an IIP3 of +3.5dBm, an IIP2 of better than +48dBm, a noise figure of 11.5dB, an LO to RF isolation of 60dB at 8GHz and consumes 6.9mW of power from a 1V supply. The proposed quadrature generator circuit features a new architecture which embeds the quadrature generation scheme into the LO-buffer using active inductors. The circuit offers easy tune-ability for process, supply and temperature variations by relaxing the coupling between amplitude and phase tuning of the outputs. The implemented circuit occupies an area of 150 x 90m2 and exhibits an amplitude and quadrature phase accuracy of 1 dB and 1.5° respectively over a bandwidth of 100 MHz with a power consumption of 12mW from a 1V supply including the LO-buffer. The quadrature down-converter features an image rejection ratio of better than 40 dB and satisfies the potential target specifications of future mobile phones, extracted in this work.

No description available.

No description available.

Fully integrated Ultra-Wideband (UWB) RFIC transmitters are designed in Si-based technologies for applications such as wireless communications or sensor networks. UWB technology offers many unique features such as broad bandwidth, low power, accurate position location capabilities, etc. This research focuses on the RFIC front-end hardware design issues for proposed UWB transmitters. Two different methods of multiband frequency generation ----- using switched capacitor VCO tanks and frequency mixing with single sideband mixers ----- are explored in great detail. To generate the required UWB signals, pulse generators are designed and integrated into the transmitter chips. The first prototype UWB transmitter is designed in Freescale Semiconductor 0.18μm SiGe BiCMOS technology for operation over three 500 MHz bands at center frequencies of 4.6/6.4/8.0 GHz, and generates pulses supporting differential BPSK modulation. The transmitter output frequency is controlled by a two-bit code which sets the state of a switched capacitor tank array for coarse tuning of the VCO. While selecting between the different bands, the transmitter is capable of settling and re-transmitting in less than 0.7μs using an integrated, wide band phase-locked loop (PLL). Various issues such as mismatch/inaccuracy of the pulses and high power consumption of the prescaler were identified during the first design and were addressed in subsequent design revisions. The pulse generator is a critical part of the proposed UWB transmitter. The initial pulse generator design used CMOS delay lines and logic gates to synthesize the required pulse bandwidth; however this approach suffered from inaccurate pulse timing control due to delay time sensitivity to device modelling and process variations. Subsequently, a novel pulse generator design capable of achieving accurate timing control was implemented using digital logic and a fixed oscillator frequency to provide timing information, integrated into a modified transmitter circuit, and subsequently fabricated in Jazz Semiconductor's 0.18μm CA18 RFCMOS process. Experimental results confirm the generation of accurate one-nanosecond pulses. Finally, a new multiband UWB transmitter based on a new single sideband (SSB) resistive mixer with superior linearity and zero static power consumption was also designed and fabricated using Jazz CA13 0.13μm RF CMOS process. This design is based on a fixed frequency phase-locked VCO and generates different bands through frequency mixing. In the prototype design, two additional carrier frequencies are generated from the VCO center frequency (5 GHz) by mixing it with its output divided-by-4 (1.25 GHz). By switching the relative I/Q phases of the LO/IF inputs to this single side band mixer, either the upper side band (6.25 GHz) or lower side band (3.75 GHz) frequency is selected at the mixer output, while the other sideband is rejected. Simulation results show that the transmitter is capable of generating the desired carrier frequencies while suppressing the image component by more than 40 dB. Overall, this work has explored various aspects of UWB transmitter design and implementations in fully integrated silicon chips. The major contributions of this work include: proposed hardware architectures for pulse-based multiband UWB transmitters; implemented a fully integrated multiband UWB transmitter with embedded phase-locked switched-tank VCO capable of wide frequency tuning; demonstrated an all digital pulse generator capable of generating accurate one-nanosecond pulse trains in the presence of various mismatches; and investigated resistive SSB mixer topologies and their implementation in a multiband UWB generation architecture. / Ph. D.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / RF and IF signals must be down-converted to lower frequencies to allow storage on tape. Pre-Detection converters avoid signal distortion created in later receiver stages, however should not add noise and distortion with their conversion process.

Coriolis meter, despite being very accurate in single phase conditions, fails to accurately measure two-phase flows. It poses a complex fluid-structure interaction problem in case of two-phase operation; there is a scarcity of theoretical models available to predict the errors reported by Coriolis meter in aforementioned conditions, hence the need for experimental research. Experiments are conducted in both single and two-phase flow conditions. Meter accuracy is excellent in single phase conditions and no significant effect is observed on use of flow conditioners, namely inlet swirl and inline mixer. Operational two-phase envelope is determined through experiments at different flowrates. Flow conditioners are used to study the effect of phase segregation and homogenization on accuracy of the meter. Testing is done to cover two-phase flows from both extreme ends, namely aerated liquids and wet gas. Use of flow conditioners show slight improvement in meter accuracy on use of inline mixer, and reduction in accuracy in case of inlet swirl, when both former and latter are compared to results obtained from experiments with no flow conditioners. The difference in accuracies between results with flow conditioner and without flow conditioners is attributed to relative motion between the phases, which is more in case of inlet swirl, due to larger bubble sizes. Flow conditioners show an insignificant effect on meter accuracy during wet gas tests. The reason proposed is annular flow regime, which is not highly affected by flow conditioners. Single phase tests demonstrate that Coriolis meter gives accurate measurement even in presence of severe flow disturbances. There is no need for flow conditioning before the meter to obtain accurate readings from it, which would be the case in other metering technologies like orifice and turbine. In two phase flows, the meter reports negative errors, which is consistent with previous experimental works available in literature. Use of flow conditioners clearly affects the reading of the meter in aerated liquids. This phenomenon can be used to get fairly accurate estimate of flow rate in low gas volume fraction liquid flows.

Coriolis meter, despite being very accurate in single phase conditions, fails to accurately measure two-phase flows. It poses a complex fluid-structure interaction problem in case of two-phase operation; there is a scarcity of theoretical models available to predict the errors reported by Coriolis meter in aforementioned conditions, hence the need for experimental research. Experiments are conducted in both single and two-phase flow conditions. Meter accuracy is excellent in single phase conditions and no significant effect is observed on use of flow conditioners, namely inlet swirl and inline mixer. Operational two-phase envelope is determined through experiments at different flowrates. Flow conditioners are used to study the effect of phase segregation and homogenization on accuracy of the meter. Testing is done to cover two-phase flows from both extreme ends, namely aerated liquids and wet gas. Use of flow conditioners show slight improvement in meter accuracy on use of inline mixer, and reduction in accuracy in case of inlet swirl, when both former and latter are compared to results obtained from experiments with no flow conditioners. The difference in accuracies between results with flow conditioner and without flow conditioners is attributed to relative motion between the phases, which is more in case of inlet swirl, due to larger bubble sizes. Flow conditioners show an insignificant effect on meter accuracy during wet gas tests. The reason proposed is annular flow regime, which is not highly affected by flow conditioners. Single phase tests demonstrate that Coriolis meter gives accurate measurement even in presence of severe flow disturbances. There is no need for flow conditioning before the meter to obtain accurate readings from it, which would be the case in other metering technologies like orifice and turbine. In two phase flows, the meter reports negative errors, which is consistent with previous experimental works available in literature. Use of flow conditioners clearly affects the reading of the meter in aerated liquids. This phenomenon can be used to get fairly accurate estimate of flow rate in low gas volume fraction liquid flows.

IEEE 802.15 High Rate Alternative PHY task group (TG3a) is working to define a protocol for Wireless Personal Area Networks (WPANs) which makes it possible to attain data rates of greater than 110Mbps. Ultra Wideband (UWB) technology utilizing frequency band of 3.168 GHz – 10.6 GHz is an emerging solution to this with data rates of 110, 200 and 480 Mbps. Initially, UWB mode I devices using only 3.168 GHz – 4.752 GHz have been proposed. Low Noise Amplifier (LNA) and I-Q mixers are key components constituting the RF front-end. Performance of these blocks is very critical to the overall performance of the receiver. In general, main considerations for the LNA are low noise, 50 broadband input matching, high gain with maximum flatness and good linearity. For the mixers, it is essential to attain low flicker noise performance coupled with good conversion gain. Proposed LNA architecture is a derivative of inductive source degenerated topology. Broadband matching at the LNA output is achieved using LC band-pass filter. To obtain high gain with maximum flatness, an LC band-pass filter is used at its output. Proposed LNA achieved a gain of 15dB, noise figure of less than 2.6dB and IIP3 of more than -7dBm. Mixer is a modified version of double balanced Gilbert cell topology where both I and Q channel mixers are merged together. Frequency response of each sub-band is matched by using an additional inductor, which further improves the noise figure and conversion gain. Current bleeding scheme is used to further reduce the low frequency noise. Mixer achieves average conversion gain of 14.5dB, IIP3 more than 6dBm and Double Side Band (DSB) noise figure less than 9dB. Maximum variation in conversion gain is desired to be less than 1dB. Both LNA and mixers are designed to be fabricated in TSMC 0.18µm CMOS technology.

This thesis focuses on the design of radio-frequency (RF) mixers, including a broadband downconverter mixer, an upconverter mixer and a downconverter mixer with high linearity. The basic mixer topology used in this thesis was the Gilbert cell mixer, which is the most popular mixer topology in modern communication systems. In order to accommodate different applications, the broadband mixer and the upconverter mixer were designed to be reconfigurable. First, a broadband downconverter mixer with variable conversion gain was designed using 0.13-$\mu m$ CMOS technology. The mixer worked from 2 to 10 GHz. By changing the effective transistor size of the transconductor and the load, the mixer was able to work in three different modes with different conversion gain and power consumption. Second, an upconverter mixer with sideband selection was demonstrated in CMOS 0.13-$\mu$m technology. The transmitted sideband could be chosen to be the upper sideband or the lower sideband. The mixer worked at 5 GHz with a 100 MHz IF. The measured voltage conversion gains were 11.2 dB at 4.9 GHz and 12.4 dB at 5.1 GHz. The best sideband rejection was around 30 dB. Third, a modified derivative superposition (DS) technique was used to linearize a Gilbert cell mixer. Simulation results predicted an IIP3 improvement of 12.5 dB at 1 GHz. After linearization, the noise figure of the mixer increased by only 0.7 dB and the conversion gain decreased by 0.3 dB. The power consumption of the mixer increased by 0.96 mW. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-06-18 14:40:35.062