Sharif Digital Repository

Breast cancer is one of the most common cancer types and is the leading cause of cancerrelated death among females according to American Cancer Society statistics. Breast screening and early detection is the most effective method of management and treatment of this disease. Currently, several imaging systems for breast cancer detection are being used among which microwave imaging has caught the attention of many as a promising tool for early breast cancer detection. Microwave imaging is considered as a non-invasive, relatively low-cost, Fast, convenient, and safe method for breast cancer screening. this research aims to implement a 3D imaging system that operates based on the microwave... 

Morphology and alignment of endothelial cells (ECs) have great influence on plaque formation. These alignments are based on the cyclic strains and wall shear stress (WSS) on the arterial wall. In the present study, cyclic strains and WSS are investigated to predict the secondary plaque locations downstream of the primary stenosis. Therefore, left coronary artery (LCA) with its branches to left anterior descending (LAD) and left circumflex (LCX) are 3D located on a virtual sphere to consider the cardiac motion. Stenoses are placed at the beginning of the bifurcation with varying degrees from 40% to 70% based on diameter reduction. Healthy coronary is also constructed to compare with those of... 

In this thesis, the design of a fully-integrated Millimeter-wave Broadband power amplifier in TSMC 0.18 µm CMOS technology is studied. The Darlington cell with cascode topology was adopted as the power cell to improve the maximum available gain of transistors in standard 0.18 µm CMOS technology to make it eligible of operating at Ka band. Furthermore, by proposing a new topology as an improved Darlington-cascode with intermediate inductor in the Darlington pair, the improvement in flat power gain at Ka band and more importantly, in available power gain of active element at high frequencies of the Ka band is achieved. The proposed power amplifier is a two stage structure with the driver stage... 

In this thesis, a low-power low-phase-noise 28 GHz voltage-controlled oscillator for 5G applications is presented. At first, to select the best structure in terms of FoM, various types of inductors and transformers have been designed and EM simulated. The class-C structure which leads to the highest FoM is chosen eventually. In order to increase oscillation amplitude and reduce phase noise while preserving FoM, a high-frequency noise filter is presented. This filter which is based on a λ/8 microstrip transmission line has solved the conventional filter problems e.g. narrow bandwidth, coupling with oscillator inductor and practical implementation issues.The oscillator is designed, EM... 

The blood pressure (BP) is one of the most vital signs to monitor human health. Hypertension is a major public health problem that is associated with morbidity and mortality. In the past decades, the number of people with hypertension disease has been increased. According to Ministry of Health, 54 percent of hypertensive patients are unaware of this health threat. Therefore, accurate and continuous measurement of BP is essential for its prevention and treatment. Traditional non-invasive methods of BP monitoring use an inflatable cuff, which causes discomfort due to occlusion of the artery and can not be used continuously. Numerous studies have attempted to present methods without using a... 

The thesis opens with a discussion of the distinction between some of the classical and the constructive notions in mathematical analysis. There then follows a description of the three main varieties of modern constructive mathematics: Bishop’s constructive mathematics, the recursive constructive mathematics of the Russian School, and Brouwer’s intuitionistic mathematics. The main purpose of the thesis is to prove the independence, relative to Bishop’s constructive mathematics, of each of the following statements:There exists a bounded, point-wise continuous map of [0, 1] into R that is not Lebesgue measurable.If µis a positive measure on a locally compact space, then every real-valued map... 

In this study، a novel frequency multiplier chain for wideband millimeter-wave applications at 28 GHz is presented. Millimeter-wave imaging systems require high frequency and wide bandwidth to accurately detect hidden objects. Various methods have been proposed to increase the frequency of generated signals, but in the meantime، frequency multiplier structures exhibit better performance in terms of bandwidth، power consumption and, harmonic rejection. These circuits are widely used in High-frequency telecommunication systems such as 5th generation mobile services. To design a frequency quadrupler، two multiplier stages based on the improved quadrature Gilbert structure were used. Generating... 

Automatic classification of different sleep stages is an important and challenging research topic in the field of biomedical signal processing. The methods proposed so far for this purpose have been based on multi-channel physiological signals such as electroencephalogram , electrooculogram, and electromyogram . These signals can provide valuable information about the individual's sleep pattern and stages, but their use in a home environment is limited due to the need for complex equipment and specialized skills. Therefore, the development of a sleep stage classification method based on a single-channel signal that can achieve this goal with high accuracy without the need for complex... 

Design of a 28GHz phased array receiver front-end for 5G applications in CMOS 0.18um technology in the frequency band from 27.5 to 28.3 GHz is presented in this thesis. We use an RF phase shifting structure which consists of a low-noise amplifier, a phase shifter and a power combiner. The low-noise amplifier is designed using common-source cascode topology with a transformer-based gm-boosting technique in order to enhance the power gain and reduce the noise figure. A vector sum phase shifter is then designed to further enhance the gain. A Wilkinson power combiner with lumped elements is designed as the power combiner. The results of simulating a single RX chain shows a maximum of 15 dB... 

Power harvesters are used to generate energy for electronic devices. These electrical energy generators consist of three main parts: energy source, power electronic converter and energy storage. In order to minimize some of the weaknesses of these devices, including low power density and low reliability, the hybrid power harvesting method can be utilized. In this thesis, we design and build a hybrid energy harvester considering the advantages of simultaneous usage of solar and thermal energies for a wearable sensor, focusing on "efficiency enhancement" and "availability improvement". In the designed device, both solar and thermal energy harvesting units operate independently. In the solar... 

On the demand of higher directivity, higher throughput and less interference, phased array systems and MIMO have become attractive to reach these goals. The advantages of phased array systems include the ability to perform electronic beam steering and arbitrary pattern synthesis. Phase shifters and variable gain amplifiers are used to reach these advantages. In this thesis, a ‘’ C‘’ band (4.8 GHz-6.2 GHz) vector-sum phase shifter using HMIC technology for realizing a phased array receiver is designed. This phase shifter can change the signal phase and amplitude. The main blocks of this phase shifter are low-insertion phase and low-noise variable gain amplifier, which consists of current... 

Reliability in today's world plays a pivotal role. As technology makes progress in various industries such as aviation and defense, the need for high reliability of systems is felt more and more. In this regard, reliability is directly related to the lives of people, and its high level can play a significant role in the profitability of organizations. Selective Maintenance, as one of the research areas in the field of reliability optimization, strives to enhance the reliability of the system and minimize the costs of the system by finding optimal maintenance policy. In the models that have been presented to optimize the selective maintenance policy, the assumption that the repair cost of... 

Today's millimeter imaging has been widely used in the field of security and medicine. With increasing security threats, there is a need for improved security equipment. Millimetric waves not only have the ability to penetrate dielectric materials, but also the ability to separate them to detect hazardous materials. Also, the millimeter-field imagery is capable of detecting different materials from each other, which is an advantage in detecting hidden cases. Unlike X-ray imaging, millimeter waves do not have the ability to ionize the cells of the body, which reduces the risk of creating radios for imaging. In this project, an array antenna with two orthogonal poles is designed. Macrostrip... 

This thesis contributes to development of a microscopic simulation of arterial traffic flow to estimate the impact of behaviour and culture of Iranian drivers on fuel consumption. To accomplish this task it is necessary to use a simulation software. But as existing simulation softwares include assumptions which are not applicable to traffic culture and architecture in Iran, a new software was developed. This software is based on non-lane disciplined driving parameters. The output is an estimation of average consumed fuel by a vehicle in general or a specified service condition. This estimation is an important parameter in decision making and planning for the future traffic and environmental... 

This thesis presents a four-antenna phased-array transceiver front-end for 5G applications. The designed front-end uses RF architecture and time division duplexing mode and operates in the 26~30 (GHz) band. In our design procedure, we have used a four-stage inductively degenerated common source LNA, a differential three-stage PA, and a vector-sum phase shifter. Circuit blocks are connected using traditional architecture, and an SPDT switch is used to determine the Tx/Rx mode of the system. A switching current reference is designed, which enables us to control the circuit gain over different process corners and temperatures.Each transmitter chain produces 13.42 (dBm) power at its operating... 

With the expansion of wireless communication technology and the advent of the fifth generation of mobile communication, there is a growing need for broadband systems. Consequently, RF engineers are currently focusing their attention on broadband transceiver systems. The low noise amplifier (LNA) is a critical component in the receiver of a telecommunication system. In this research, the design of a broadband LNA in the K and Ka frequency band (18 ~ 40 GHz) is presented. The main challenge in designing a broadband LNA lies in achieving simultaneous power matching and noise matching through the input impedance matching network. Various types of broadband impedance matching networks have been... 

Supersonic impinging jets, similar to the jet flows exhausted from a nozzle, generate high unsteady pressure and acoustic loads on the rocket payload or the VTOL aircraft structure with possible mission failure during the launch/starting phase. In the past, experimental studies were concentrated on characterizing the steady impingement flow and not the initial transient process. It was shown that one of the main characteristics of supersonic impinging jets is the dominance of the feedback loop mechanism. The present investigation is an attempt to examine the flow characteristics of a high temperature supersonic impinging jet through a convergent-divergent nozzle during the transient starting... 

In this project Ni-SiC nanocomposite coatings were electrodeposited using Watts nickel bath with addition of SiC particles to the bath. Optimization of Ni-SiC electrodeposition parameters was done using Response Surface Methodology (RSM). At specific conditions, 67 Vol% of 10nm SiC is incorporated in nickel electrodeposits which is unique and not yet reported. Study nanomechanical properties of these coatings using Nanoindentation method, it was realized that the dislocation density is increased as force increasing which is in agreement with increasing intensity of (220) and (200) reflections and intensity attenuation of (111) reflection. Nanoscratch tests show that these... 

Today, by emerging wearable technologies and digital health, it is possible to constantly monitor vital signals of people without time-consuming and costly referrals to medical centers. Applications of wearable sensors for health monitoring include electrocardiograms (ECG), blood pressure measurement, and blood sugar measurement, etc. One of the important fields of health monitoring is cardiac arrhythmia detection. Cardiac arrhythmia is any kind of anomalies in heart beat rhythm that can lead to serious damage to vital organs of the body. It is estimated that between 750 thousand to 1.5 million people are facing cardiac arrhythmia in Iran. Therefore, early detection of cardiac arrhythmia is...