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Design and realization a quasi yagi antenna array and its feed system printed on a ceramic substrate for x-band radar applications

Atabay, Berkay
This thesis includes design, simulation, realization and measurement of a four-element quasi- Yagi antenna array printed on a ceramic substrate for X-band radar applications. The microstrip array antenna is designed using four quasi-Yagi antennas in a linear configuration and is printed on Alumina 99.6% substrate made by Coorstek Corporation. The antenna can fit into small areas because of compact structure due to the use of high dielectric constant substrates. In addition, the use of alumina ceramic substrates provide resistance in heating stroke which may be critical in many applications. These properties make this design an appealing choice as a radiating element. Especially in radar applications antenna parameters such as gain, return loss, impedance bandwidth (BW) are investigated in the single element as well as the array environment. Mutual coupling between the array elements is also predicted. The quasi-Yagi radiator employed as radiating element in the array measured an exceptional impedance bandwidth of 52% for a S11< -10 dB from 7.5 GHz to 12 GHz, with 3 dB to 5 dB of absolute gain in the same frequency range. The antenna consisting of a microstrip line feed and microstrip to coplanar stripline transition (Balun). The microstrip array antenna is designed and simulated using Ansys HFSS, a high frequency electromagnetic field simulation program. Then to investigate the effects of all parameters a parametric study is performed using HFSS. The four coplanar strip dipole antennas and feeding mechanisms are designed and simulated with appropriate power divider structure. This equal power divider can operate at X-Band and designed with AWR program. Finally, the antenna element and four-element uniform linear array antenna are manufactured with thin film technology, measured, and their performances are compared with simulation results.