الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This thesis is devoted to introduce a new technique for high resolution phase shifter for mOdem radar phased array antennas. The implemented circuit is simple and suitable for radar systems. MEMS switches are used to achieve lower power dissipation, lower insertion loss, and lower return loss in comparison with electrical switches such as PIN diodes and FET. The designed high resolution phase shifter is developed to be wide band width and suitable for a wide bandwidth surveillance radar antennas. The basic concept in widening the phase shifter bandwidth is that the total insertion phase of cascaded stages is the algebraic sum of insertion phases of each individual stage. A circuit of microstrip RLC elements can be used as a widening circuit for RP signal.The proposed phase shifter is controlled using 8-bit decoder circuit to give two degrees resolution for scanning in azimuth and half degree scanning in elevation for hemi-sphere scanning antenna. The phase shifter is designed, simulated, and tested using simulation program (ADS). Advanced Design System (ADS) is an electronic design automation software system produced by Agilent EESOF EDA, a unit of Agilent Technologies. The proposed phase shifter is applied to conical conforma1 antenna. Conformal antenna with conical shape can steer the beam electronically in both azimuth and elevation to cover a hemisphere mesh surrounding the radar antenna. This overcomes limitations of mechanical steering and dead cone and improves the radar capability in tracking. Elements weight of conical array antenna is optimized using genetic algorithm. Optimization process improves the beam pattern peak side lobe level while maintaining a narrow beam width. A high resolution phase shifter and adaptive attenuator can be used for each element to get the desired phase and the optimum weight for conical array beam pattern. Thesis is divided mainly into three sections. First section illustrates how the proposed high resolution phase shifter operates using course and fine tuning to give 360 degrees phase shift with two degrees resolution. Second section presents the main idea of widening the phase shifter bandwidth using RLC microstrip elements. The later one gives an application for the proposed phase shifter as a part of digital feeding network to a conical array antenna.