Sharif Digital Repository

Nowadays, optical networks is one of the best options for ultra high speed data transmission. An optical network is either implemented using optical fibers or via free space optical links. Fiber optics has gained special popularity among all mediums of data transmission, however, builing a fiber infrastructure is not a cost or time effective solution and this is the main limitation of these networks. Free space optics has been an attractive answer to overcome the drawbacks of the fiber optic networks. On the other hand, atmospheric turbulence and scattering are the main factors affecting FSO’s availability and Reliability. As a result, Design of next generation FSO networks need high speed... 

Today, phased array antennas play 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 application of these systems at frequency band of 33-36 GHz.The... 

Nowadays, in many of industrial processes, it’s necessary to measure acceleration of a moving object. Among the different type of accelerometers, the piezoelectric type are most useful and the most widely used. These sensors come in various configurations.
In the past, analytical and semi-empirical models have been used to design piezoelectric accelerometers. In these methods, based on some assumptions, the accelerometer nonlinear model is replaced with a linear model and the equivalent circuit model has been used to model accelerometer behavior. In these methods, the behavior of accelerometer become different from the expected one.
Recently, with the invention of efficient computing... 

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...