Sharif Digital Repository

tIncreasing the bandwidth of a receiver is limited to the bandwidth of the system's internal components such as amplifiers, power dividers / combiners, and directional couplers, which are widely used in array antenna systems. Wilkinson splitters are often used for balanced power dividers and hybrid branch line couplers are used for directional couplers because their macrostrip structure makes them lighter and cheaper, and ultimately increases their use. Unfortunately, these elements provide up to 20% fractional bandwidth, which is not enough in our intended use. Also, the design of the power divider at millimeter wave frequencies has challenges such as matching impedance across all bands and... 

The main objective of this project is to analysis and design of ultra ultra wideband dual polarization vivaldi antenna array for electronic support measure system. In modern satellite communication and radar systems, antenna are required to have the characteristics of both ultra wide band and dual-polarization so as to satisfy various needs such as expanding the information volume, improving the quality of receiving information and increasing the ratio of bandwidth utilization. For this reason we first design a single element of vivaldi antenna for 6-18GHz range and then with design of SMA connector shown that result with and without SMA is same. In the next step we design(under... 

The millimeter wave (mmWave) band, a prime candidate for 5G cellular networks, seems attractive for wireless energy harvesting since it will feature large antenna arrays and extremely dense base station (BS) deployments. The viability of mmWave for energy harvesting though is unclear, due to the differences in propagation characteristics, such as extreme sensitivity to building blockages. But in this research, a scenario is considered in which low-power devices extract energy and/or information from the mmWave signals. Using stochastic geometry, analytical expressions are derived for the energy coverage probability, the average harvested power, and the overall (energy-and-information)... 

The frequency divider is one of the components of a frequency synthesizer. Regenerative frequency divider is one of the frequency division methods and is used in narrow band applications. In this thesis, the process of designing & fabricating Ka band and Ku band regenerative frequency dividers is reported. A bandwidth of 550MHz for the Ka band divider and 400MHz for the Ku band divider have been achieved. Multiple passive structures such as microstrip filters, Wilkinson power dividers and a waveguide-to-microstrip transition have been designed during the fabrication of the mentioned frequency dividers. According to the results of the simulations, the bandwidth of the waveguide-to-microstrip... 

In this thesis, study the design of a compact low-cost integrated time modulated array(TMA). In TMAs, a switch is used instead of a phase shifter, which reduces the area, complexity, power consumption and the final price of the array. The TMAs uses the switch as a control element for array weighting that causes beamforming and beam steering. For the lower cost, designed IC compacted as small as possible and use inexpensive CMOS 180nm technology of TSMC fabrication. Initially, maximum layout size forced 0.7 by 1.5 mm2. The proposed switch type is SPDT that one of its output paths terminated by a matched load and another end to a pad and then by a bond wire connected to an external board that...