Sharif Digital Repository

Nowadays, using of microwave integrated circuits in military and industry applications has been became popular, especially with the advent of monolithic microwave integrated circuits which provide possibility of fabrication of amplifiers in large volume with high precision and appropriate cost. Power amplifiers as the last block of transmitters, are such circuits that are too attractive in this area. Since high power amplifiers consume a lot of power in transistors, large amount of heat will be in the surface of chip. Loss of some of consumed power in amplifiers results increasing transistor’s channel and chip surface temperature. Increase in channel temperature results degradation in... 

Power amplifiers are used as the last block of transmitters. This block can be categorized as the one of most important part in communication systems. However, in transmitter systems which require high power to create stable link with the receivers, fabrication process like CMOS are unable to provide such level of power. Thus, designers employ another group of integrated circuits which names MMIC that offers this capability to designers. MMIC is the abbreviation of Microwave Integrated Circuit which is implemented in compound substrates like GaAs. Monolithic microwave integrated circuits enable the implementation of amplifiers in small size, large number, with high precision and appropriate... 

In this thesis, we try to design and implement a low noise, low power consumption CMOS direct conversion mixer with LO-2LO topology. Direct conversion mixers have two differential I,Q outputs. Because of zero intermediate frequency, flicker noise is critical. This mixer is designed for UHF band in TSMC CMOS 0.18µm technology. Total current consumption of I,Q mixer is less than 3mA .Voltage conversion gain is about 23 dB and DSB noise figure is less than 3.5 dB. Some conventional thermal and flicker noise cancellation has been used simultaneously to reduce noise figure. New noise cancellation techniques are proposed to get further improvement in noise figure with negligible extra current... 

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... 

Advancement in the field of electronics can often be observed from the improvement in performance of active circuits and systems. The amplifier, because it is a highly versatile functional circuit, has always been one of the first to benefit from new developments. Of the many characteristic of an amplifier, perhaps the most notable are the gain and the frequency response. In many applications, both the gain and the bandwidth need to be optimized. One of the most significant structures which have proper gain and bandwidth, are distributed amplifiers. But these structures are nonsymmetrical and have many active loops. As a result, the stability analysis of distributed amplifier is quite... 

Today using of microwave integrated circuits in commercial and military applications is paid attention too much, especially with emerging of monolithic microwave integrated circuits that prepares for us producing of amplifier with mass production, enough accuracy and proper cost. Power amplifiers that used in the end of transmitter path are paid attention in this field. However,in transmitter systems which require high power to create stable link with the receivers, fabrication process like CMOS are unable to provide such level of power. Thus, designers employ another group of integrated circuits which names MMIC that offers this capability to designers.MMIC is the abbreviation of Microwave... 

Nowadays, application of microwave integrated circuits in commerce and humanitarian military measures plays an important role. When integrated microwave circuits emerged, the dream of producing high quality and low cost amplifiers and mass productionhas been fulfilled. Power amplifiers which are the last block in a communication systemare one of the most important circuits in this field.
Since driver amplifiers are interstage between high and low power sections of a system, should have good specificationsfor both small and large signal analysis. Thus, designing such a circuit can be very challenging. In order to get the desired bandwidth, high-order filters are used as interstage... 

This project proposes a novel design technique for implementation of class-EM power amplifier (PA). Class-EM mode of operation has been proposed as the improved version of class-E; outclasses in terms of efficiency as well as power gain. Specifically, provided that the current fall time of switch is an appreciable portion of a period; frequency of operation is high enough that the switching time of transistor can no longer be considered instantaneous in other words. A novel technique for harmonic injection required for class-EM operation is proposed. Followed by the system of equations and the design methodology governing the proposed circuit. As a proof of concept and verification of 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... 

Today usage of microwave integrated circuits in commercial and military applications is very common, especially with emerging of monolithic microwave integrated circuits that make mass production with good quality and price possible. A lot of attention are paid to designing power amplifiers used in the end of transmitter line. Because of power dispersion in transistor channels, high power amplifier causes excessive heat on the chip. Channel temperature increasing, causes operation retrogradation in circuits that result in destruction of the chip. So it is necessary to transfer this heat to the outside from the chip. It is usual to use a heatsink for this problem, however for low thermal... 

In recenet years the use of microwave integrated circuits for military and commercial applications has gained much more attention. The advent of monolithic microwave integrated circuits, which provide the possibility of fabrication of amplifiers in large number, sufficient accuracy an affordable price has accelerated this process. Low noise amplifiers as the first blocks in the receiver modules are such circuits that are highly regarded in this field. This block is a key block in the receiver which its noise figure and gain directly affect the sensitivity and dynamic range of the receiver. As a result, a low noise amplifier with low noise figure, high gain, good return loss, low power... 

Power amplifiers are used as the last block of transmitters. This block can be categorized as the one of most important part in communication systems. However, in transmitter systems which require high power to create stable link with the receivers, fabrication process like CMOS are unable to provide such level of power. Thus, designers employ another group of integrated circuits which names MMIC that offers this capability to designers.
MMIC is the abbreviation of Microwave Integrated Circuit which is implemented in compound substrates like GaAs. Monolithic microwave integrated circuits enable the implementation of amplifiers in small size, large number, with high precision and... 

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... 

In this thesis, a power switch with a smart driver is designed. 4-ampere current can pass through the switch, and the driver is capable of switching the load with 50 kHz frequency. The smart driver consists of an internal oscillator, internal regulator, charge pump, current limit, a level shifter, overtemperature and over/under voltage circuit. All these circuits are designed and developed in high voltage BCD 0.18 um process and well discussed in the thesis. All four kinds of protections are designed and implemented; open load detection, short circuit detection, over temperature shut down, UV and OV detection. Charge pump idea is used instead of the bootstrap method, which makes it possible... 

Todays the use of microwave integrated circuits for military and commercial applications has gained much attention, especially riththe advent of monolithic microwave integrated circuits, which provide the possibility of fabrication of amplifiers in large number, sufficient accuracy and affordable price.GaAs pHEMT process, because of good characteristics for noise and power in high frequencies, is a good choice for microwave and millimeter wave integrated circuits. A low noise amplifier is a key block in the receiver and, its noise figure, gain and linearity directly affects the sensitivity and dynamic range of the receiver. Hence, a low noise amplifier with low NF, high gain, good return... 

RF Receivers are one of the main components of telecommunication systems, which can be composed of many parts and circuits according to their working frequency and application.In this thesis, the design and simulation of an X-band Receiver in 0.15um GaAs technology has been discussed. The receiver chain, in the order of receiving the signal, includes the main blocks of limiter, attenuator, low noise amplifier and mixer. It also includes a number of filters. The attenuator has two digital bits and the receiving chain filters are implemented in such a way to provide more than 20dB attenuation in the frequency band of the image signal. In this research, the limiter is implemented with a... 

Estimating the life-time of electronic devices has always been an important issue in their mass production. Nowadays, electronic chips are widely used due to technological advances and due to their smaller size. They may be more likely to break down because of their complexity. Therefore, estimating their life-time has received much attention. In the first chapters of this thesis, the concepts and standards that exist in the field of reliability and the life expectancy of electronic devices are discussed. There are many reasons for chip failure, which are beyond the scope of this thesis but what is known as the most important cause of failure which is named electromigration has been... 

In this project, an inverting Buck-Boost converter with two negative linear regulator is designed, implemented and measured in CMOS 0.18μm-HV BCD technology. Input voltage of Buck-Boost converter can vary from +15V to +28 and output voltage is digitally adjustable from -1V to -10V. Maximum output current of the converter is 300mA. A current mode controller and a lag compensator is used to control the converter. A high speed highside current sensor is designed and used in current mode controller. Sampled current of the current sensor is also used in a current limit circuitary to limit the maximum current of highside switch. Two negative linear regulators are placed at the output of the... 

In this thesis, a transceiver chip compliant to Controller Area Network (CAN) protocol has been designed and implemented in High Voltage BCD 0.18um Technology.This RX/TX chip contains a transmitter, normal and low power receivers.In the transmitter, CAN bus common-mode voltage is sampled with a voltage sampler circuit and compared with a reference voltage. Receiving a control signal, the transmitter slop control circuit varies the speed turning output transistors on and off in order to keep transmitter Electromagnetic Emission (EME) as low as possible. In the receiver, a new method for bus common mode voltage rejection is introduced. By using a V-I converter block and a current subtractor... 

Efficiency of a power amplifier (PA) as the most power consuming block of a cellular transmitter is crucial. In modern wireless communication systems, the use of spectrally efficient modulation scheme will result in signals with high peak to average power ratio. This means that a cellular PA operates at average output power most often. Thus, low PBO efficiency of a cellular PA could result in lower battery life and thermal problems. As a result, the PA power back-off (PBO) efficiency is as important as its peak efficiency in these applications. In conventional classes of PA like class AB and B, efficiency rapidly degrades with output power reduction. Thus, PBO efficiency improvement...