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 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... 

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... 

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... 

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... 

One of the most important parameters of a smartphone is the ability to operate in a long time with a rechargeable battery. As a result, the design of radio frequency circuits which are used in these cell phones is a consistent challenge for designers. Bluetooth Low-Energy standard (BLE) which is the fourth edition of Bluetooth standard is recently introduced with the aim of transporting low volume data with minimum power consumption. The most important challenge of the design of an RF receiver in the BLE standard is the power consumption. In a typical receiver, the oscillator and the mixer are the most power hungry blocks. Therefore, decreasing the power consumption of these two blocks is... 

Thus far numerous components and devices have been designed and realized based on plasmonics. Hereon, we focus on PlasMOStor which is probably the first and most important CMOS compatible plasmonic modulator. It resembles to its electronic counterpart MOS transistor in geometry, unless, it has a plasmonic waveguide instead of the regular channel to modulate optical signals . By applying voltage to the gate and inset of charge carrier accumulation, optical properties of the channel changes and plasMOStor turns off. In this thesis, we carry out a through investigation of plasMOStor’s operation. We show that the proposed theoretical description of plasMOStor is fallacious. Subsequently,...