Sharif Digital Repository

A new class of design has been introduced in the RF circuits and Frequency Synthesizers, which is based on the digital circuits. Implementation of the digital synthesizers suppresses the need to use loop filter and thus reduces the loop lock time. In this thesis different topologies of digitally controlled oscillators using inductor and capacitor tank and all digital architectures used in high frequency all digital synthesizers in 0.18um CMOS technology has been inspected and simulated. Novel techniques introduced to improve the ring oscillator-based design’s specifications which doesn’t need inductor. Using the introduced techniques, the phase noise has been lessened acceptably with respect... 

Integration of radio transceivers results in developing low power low cost wireless systems and allows delivery of multimedia contents to battery-powered mobile terminals. Portable reception of digital video for hand-held devices is one of the applications, for which, some telecommunications standards have been developed in the recent years. This research deals with the integrated implementation of the radio frequency parts of the digital video receiver, especially the frequency synthesizer. The key aspects of the digital video reception system are the required signal to noise ratio, which is relatively high, wide band input signals and strong interferers in the receiving band.
In... 

Nowadays, general electronic devices such as computers, notebooks, cellular phones and etc. are supporting Bluetooth, RFID and Zigbee standards. By integrating all of RF sections of mentioned standards, total power consumption, occupied area and total cost and price will be decreased. RF devices communications with maximum bandwidth and data rate with minimum power consumption are the main purposes in designing RF and digital building blocks. Bluetooth and Zigbee standards are applied for networking the desired RF devices. RFID standard is providing automatic identifications, item tracking and tracing, item management and inventory. RFID standard makes the communication between Tags and... 

In recent years, lots of efforts has been done to implement Ultra-Wideband (UWB) Low Noise Amplifiers (LNAs), and Reconfigurable Low Noise Amplifiers, to achieve low Noise Figure (NF) and power dissipation, and high gain and linearity. In this thesis an Ultra-Wideband CMOS Low Noise Amplifier is presented. Due to really low power consumption and extremely high data rates, the UWB standard is popular in the consumer market. The LNA is the outer most part of an UWB transceiver, which provides enough gain to the signal with the least possible noise and distortion. 0.18u CMOS technology has been chosen for the design of the LNA at the transistor level. Two different bandwidths in a single LNA... 

A lot of efforts to make CMOS integrated wireless systems have been made in the past few years. One of the most challengeable parts of wireless systems is power amplifier designing with high output power (Watt Level). Power amplifier linearization and efficiency are the most important parameters. Today, high linear and efficiency power amplifier designing is one of the most important designer challenge of integrated circuits in wireless networks. Generally, there is one inverse relation between linearization and power efficiency. So, circuit and system solutions have been suggested that high efficiency nonlinear switching power amplifier with linearization techniques and linear power... 

This project introduces a topology enabling a Low-Noise Amplifier (LNA) not only to attenuate the unwanted signals at the input stage but also to satisfy the input matching requirement in an ultra wide frequency band. Moreover, a single ended to differential signal conversion method is proposed. This method employs a noise reduction idea, so it has a lower noise figure compared to the other introduced methods with the same purpose. The introduced methods have been utilized in designing two 0.18μm reconfigurable CMOS LNAs. One of the designed LNAs covers 2.3-3.6 GHz band width and the other one covers the UHF (470-860MHz) band. Stringent sensitivity requirement, presence of strong in-band... 

High speed data converters are very often used in telecommunication systems. Since these systems are increasingly used in mobile form reducing the power consumption in these circuits is of great importance. The goal of this project was to design a pipeline 10 bit converter for a sample rate of 40 M sample/s with a power consumption of 20mW for the input level of 1Vp-p and a 1V power supply in 0.13μm CMOS technology. To reach these goals a number of low-power techniques are proposed in various levels of abstraction. In system level, the sampling and feedback capacitors, as well as the stage resolution of the ADC is optimized analytically which leads to simple back-envelope formulas to... 

Considering the drastical increasing of greenhouse gases in the atmosphere, especially carbon dioxide, reduction of these gases seems necessary to combat global warming. Fossil fuel power plants are one of the main sources of CO2 emission. In this thesis, CO2 capture from a natural gas fired combined cycle power plant using different oxygen percent in air feed is studied. Aspen Plus was used to evaluate the effect of this capture technology on the plant efficiency and energetic parameters of the system. Aspen Hysys is used to simulate Amine absorption tower and Air Separation cryogenic tower. Since the oxygen production plant, CO2 capture and transport are cost and energy intensive, the cost... 

ADC is one of the key functional blocks of any mixed signal system and therefore must be optimally designed concerning power, performance, resolution and silicon area. Among different architectures have been employed up to now, successive approximation register ADCs are known as the ones with lower power, more simplicity and lower sampling rate. Benefiting from scaling down the CMOS technology results in higher sampling rate and lower power SAR ADCs replacing other types of ADCs. To achieve the desired ADC performance, efforts are usually focused on the improvement of circuit techniques as well as on the introduction of new or combinational architectures based on SAR ADCs. This thesis aims... 

This research examines the issues of design and fabrication of Phase Shifter circuits on Silicon substrates. The Phase Shifter circuits are designed to have wide operation band width. They also should have very low sensitivity to process and temperature variation. A six bit phase shifter is designed at this research. We use a new topology for implementing the small phase shift steps and some circuits have been designed which their phase shifts can be adjusted after fabrication. All circuits are implemented with the 0.18µm CMOS technology. The research also explains all the necessary steps for measurement of fabricated circuits. The result of measurements shows good agreement with the... 

Diabetes is one of the most catastrophic diseases in the world. There will be an end to patients’ problems if scientists can invent the artificial pancreas, but there is no implantable sensing core available. All of the sensors used for measuring blood glucose level were based on an electrochemical sensor which will generate a glucose level dependent electric current. The chemical structure of that sensor will deny its usability for in vivo applications. By exploring several biological and electrical literatures we introduced a fully electrical method for sensing the blood glucose level by impedance measurement. In this thesis we introduced a new method for sensing the blood glucose... 

Impedance spectroscopy is known as one of the important integrated sensing methods in micro scale Biosensors and electrochemical sensors. Recently, Impedance spectroscopy has been noticed in many micro scale applications. These micro scale applications is being developed specially in bioelectronics and biomedical. The goal of this thesis is designing an on-chip impedance spectroscope system for high frequency with 10 bits resolution via fully electrical blood glucose concentration measurement. This system extracts the blood glucose concentration data through measuring the permittivity coefficient of blood at 1 GHz frequency. In this thesis, new method for high frequency high resolution... 

In this project, issues related to designing and fabricating active phase shifter blocks on the silicon substrate have been examined. Phase shifter circuits are designed in a way that have the most bandwidth and the less sensitivity to process characteristics changes and environmental conditions. The purpose of this research, is designing an active 6 bits phase shifter. The active phase shifter synthesizes the required phase using a phase interpolation process by adding quadrature phased input signals. It uses a new quadrature all-pass filter for quadrature signaling with a wide bandwidth. Also substitute structure has been suggested to this filter which is the main block in determining... 

Phase shifters are commonly used in the implementation of phased-array antenna systems.The function of these systems is highly dependent on the performance of phase shifters. In addition, phase shifter circuits are used in some applications such as antenna test and regulation, power amplifier linearization, and QAM modulator implementation, to name but a handful. In this project, design of phase shifter blocks, as well as limitations of fabrication on silicon substrate, is studied and these blocks are designed for maximum bandwidth and minimum sensitivity based on fabrication characteristics and environmental conditions. Design of a 6-bit phase shifter based on vector-sum method is the... 

Phase shifters are commonly used in the implementation of phased-array antenna systems.The function of these systems is highly dependent on the performance of phase shifters. In addition, phase shifter circuits are used in some applications such as antenna test and regulation, power amplifier linearization, and QAM modulator implementation, to name but a handful. In this project, design of phase shifter blocks, as well as limitations of fabrication on silicon substrate, is studied and these blocks are designed for maximum bandwidth and minimum sensitivity based on fabrication characteristics and environmental conditions. Design of a 6-bit phase shifter based on vector-sum method is the... 

In this dissertation a special category of RF filters known as multi-path filters are introduced, chracterized and implemented. The center frequency of the multi-path filters can be tuned by changing the frequency of the clocks applied to the filter, which makes them attractive for use in multi-standard receivers. In this thesis, different types of multi-path filters are studied and by proposing different circuits, their various applications are covered. First, the concept of multi-path filters and their chracteristics are studied. Then a novel technique to analyze these filters based on Fourier analysis is proposed and then, based on this analysis, a new circuit architecture with reduced... 

Frequency synthesizers are one of the most critical building blocks of RF systems. Their task is to produce high-frequency precise and stable clock signals from a low-frequency source. The signal used in mixers to up-convert and down-convert desired signals in transceivers and the precise clock of analog to digital converters are made by frequency synthesizers. Designing frequency synthesizer, because of its lots of parameter and dependency of these parameters to each other, is a hard task which forces designers to propose new structures. In this thesis, an integer-N frequency synthesizer for Bluetooth application, with the goals of decreasing spurious tones power and settling time, is... 

Bluetooth low energy, originally developed by Nokia as wibree, was formally introduced by SIG group in 2010. It is a promising technology for internet of things (IoT) which needs ultra low power consumption. Unlike digital circuits that the power consumption decreases with technology scaling and consequently decreasing the supply voltage, the scaling has not such effect in analog circuits for two reasons. First, the power consumption of an analog circuit is mainly determined by its noise and linearity specification which in almost all cases is determined by the standard. Second, due to noise consideration, analog designers prefer to not to use the latest technology for example because of... 

In this thesis designing of analog integrated circuits of contactless smart card in 0.18 um CMOS technology has been done according to the defined specifications in the related standard. This design includes two main parts which consist of power supplying blocks and data extracting blocks. Also for designing and simulating analog section circuits a suitable model of wireless interface between card and reader is needed which is obtained by some measurements on a specific card and reader. Power supplying blocks consist ofrectifier, regulator and the reference voltage and current generator circuits. Decreasing power consumption and increasing the power efficiency factor is considered in... 

Fully integrated frequency synthesizer is one of the important system-on-chips building blocks. Among this circuit’s remarkable applications, Bioelectronics field is very common. In these applications, advanced microelectronic circuits are used in order to diagnosis and treatment of diseases. The aim of this thesis is design and implementation a wideband frequency synthesizer in a 0.18um CMOS technology. The main usage of this circuit is in a fully integrated implantable biomedical sensory chip. This circuit generates two necessary local signals in sensory chip to stimulus cells and process the information.
Frequency synthesizer is based on phased locked loop (PLL) circuit and produce...