Sharif Digital Repository

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... 

In line with developments in the technology of integrated circuits, transistors are implemented in silicon. Although the price is reduced; design is more complicated, which causes the efficiency and power consumption to face some difficulties in such design. The reason why modern GDI-based circuit is the focus of attention is that in designing a digital circuit, less power is required while more efficiency is obtained. Lowering the complexity of the logic circuit can bring about reduction of power consumption and propagation delay and decrease the circuit space. GDI-based integrated circuits resemble MOSFET transistors but have fewer transistors and higher performance capability. This study... 

Phased array systems which are used for sending and receiving electromagnetic signals in mandatory directions are widely used in today’s wireless communication, satellite communication, and radar systems. Phased array systems are composed of units called transmitter/ receiver (TR) modules. These units are connected to antennas in one end and to the combiner/divider at the other end and are playing a major role in determining the quality of phased arrays. Transmitter/Receiver units include a phase shifting circuit for controlling the phase and an attenuator circuit for amplitude control of the signal being sent or received, solid state switches and a number of amplifiers. The aim of this... 

Today, phased array antennas have important role in wireless communication systems. Utilizing optimum channel capacity, having better signal to noise ratio and, high data rate are the most important features of these systems. These systems are composed of several thousands of separated transceivers which provide possibility of directional electromagnetic radiation by changing the phase and the amplitude of the signal in each transceiver independently. So, the main components of such a system are amplifiers, phase shifters and, amplitude controllers. Also a high resolution phased array military radar system is another vital applications of these systems at frequency band of 9-10 GHz. The... 

In this thesis, a Ku-band (16.3-17.3) Variable Gain Amplifier (VGA) for realizing a phase array T/R module is designed, implemented and measured in CMOS 0.18μm technology. In order to achieve a maximum gain of 15dB and NF of 4.3dB and with the idea of improving the 1-dB compression point, two gain-stages and a novel inter-stage is proposed according to pre-distortion method. Applying this linearizing technique, makes it possible to get output P-1dB higher than 18dBm. Current steering technique is used for gain control mechanism. Gain tunabality range of 31.5dB is needed and this forces 6-bit operation with 0.5dB gain-step for the VGA. Because of loading effect of higher bits on the lower... 

In this thesis, an X band vector modulator chip in CMOS .18 um technology is designed, implemented and measured. The receiver with two RF signal path includes differential amplifier, hybrid, attenuaters, variable gain amplifiers (VGA) and power combiner blocks respectively. Capability of gain and phase control is provided by 14 digital bit. 6 bits are used to control gain of each RF path, so that changing the phase and gain of the output signal in a trigonometric quarter shall be possible. The trigonometric quarter is selected by two single pole double throw switch. Cascode structure is utilized in amplifiers stages for its stability and isolation feature. Furthermore, in order to to enhance... 

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 thesis, a new wide band variable gain distributed amplifier (VGDA) is presented. A novel approach to implement uniform gain control in the wide band frequency range of 8 – 18 GHz is demonstrated. A different technique has been employed to provide necessary DC bias current, avoiding large DC-Feed inductors. A five-section wideband VGDA has been designed and fabricated in 0.18 μm CMOS technology. The VGDA have a flat gain of 11 dB, noise figure better than 5 dB, P1dB of 14 dBm at the output, input and output matching better than -12 dB and -14 dB, respectively, for maximum gain state over the 10 GHz UWB band. The gain control range is between 3 – 11 dB with gain steps of 0.5 dB and rms... 

Few years ago, when people were talking about image sensors, the minds were automatically focusing on the pictures and photos that were/are taken for recording the memories. Nowadays, however, image sensors have prominent and unbelievable role in different aspects of our life, which "image" is only representing part of this role. A wide variety of applications image sensors can be enumerated such as, Scientific, security, medical, machine vision, ITs, biometrics, automotive, etc. To evaluate the quality of an image sensor, there are different parameters, from the dynamic range, high resolution and suitable speed to low noise, low power consumption and other parameters. The art of companies... 

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... 

Removing SAW filter from the input of a receiver makes the receiver extremely vulnerable to all sorts of blockers and interferers. It is shown in this thesis that due to existing large out-of-band blockers the linearity of the saw-less receiver has to be considerably higher than that of the conventional receivers with input SAW filter. These ever-present and unwanted signals that show up in the absence of the input SAW filter are divided into two groups of far and near out-of-band blockers and interferers. It is shown that removing these groups of unwanted signals require two distinct approaches, one for near and the other for the far out-of-band blockers. An inclusive solution to protect... 

The purpose of this thesis is designing and implementation of a Carry Skip Adder using CMOS traditional technology and Gate Diffusion Input technique (GDI). I present a carry skip adder (CSKA) structure that has a higher speed, lower energy consumption compared with the conventional one. The Gate Diffusion Input is a novel technique for low power digital circuit design. This technique reduces the power dissipation, propagation delay, area of digital circuits and it maintains low complexity of logic design  

In this project, a “Ku” band (16.3GHz-17.3GHz) 6-bit phase shifter for realizing a phase array T/R module is designed, implemented and measured in CMOS 0.18μm technology. Design specifications for this block were: RMS phase error should be less than 2.5 degree in bandwidth, better than 12dB loss and better than 16dBm input 1dB compression point. High-pass/low-pass filter structure is used to implement this phase shifter. In order to decrease phase shift error in process and temperature corners, a new structure for one of bits was introduced. This structure is less sensitive to process and temperature corners and furthermore it conSumes less area in layout, but it has more loss variation... 

A Radio Frequency Power Amplifier was designed for IS-95 standard in 0.18μm / 1.8V CMOS technology. In order to increase output voltage swing and protect gate oxide of devices, pseudo-differential cascode topology was exploited. Bondwire inductors with exact modeling were used to tune out parasitic capacitances. A low-pass, L match impedance transformation network, realized using bondwire inductors, was used at output of power amplifier. An impedance transformation network design process was developed which considers the quality factor of inductors, from the first step. Also having examined the nonlinearity phenomena in power amplifiers, a fast simulation or measurement method was proposed... 

Some applications need fast locking clock and data recovery circuits for example the circuits that operate in burst mode must lock to the data packets which are transmitting from different transmitters very quickly and in just a few bit times. In such applications open-loop clock and data recovery circuits are used because lock time in closed-loop clock and data recovery circuits is usually much longer.
In this thesis a new open loop clock and data recovery circuit based on injection locking method has been proposed. This circuit can be used in applications such as passive optical networks that need fast locking. In this architecture a super harmonic injection-locked frequency divider... 

There is a strong drive toward handheld communication devices with building blocks that are fully integrated in standard CMOS technologies. Although there are obvious cost, size, and repeatability advantages, it is particularly challenging to implement fully integrated power amplifiers with no external matching in standard CMOS under the large supply variations and harsh load mismatches present in handheld devices. This Project deals with the front-end of an Integrated RFID Reader for the UHF band. The bottleneck of the design is the design of a fully on-chip Power Amplifier. In this thesis, a new method is introduced to increase transistors breakdown voltage in a class E power amplifier.... 

Electro Static discharge (ESD) in ICs can damage them. To prevent ICs from being damaged by ESD, protection circuits must be used. These protection circuits can be either designed on chip or on PCBs, to be more protective, both can be used. In this thesis, 8 kV ESD protection circuits according to human body model (HBM) in high voltage 0.18 um CMOS technology has been designed. In this thesis, in addition to study of electro static discharge phenomenon and its protection circuits, we have designed high voltage pads which are protected against 8 kV electro static discharge according to human body model. Finally these pads have been used in automotive ICs. In this thesis, firs we have...