RADAR UYGULAMALARINDA BİRDEN FAZLA HÜZMEYLE TARAMA YAPAN DİZİ ANTEN VE ROTMAN LENS TASARIMI

Abstract

In this thesis, Rotman lens, which is an analog beamforming technique capable of directing and forming the array antenna beam at different times or simultaneously, has been designed. The lens, sequentially excited by the seven beam ports, can direct the beam in the elevation axis to -41°, -26°, -13°, 0°, 13°, 26°, and 41°. When the beam ports of the lens are fed simultaneously, the lens has the ability to simultaneously form beams at -41°, -26°, -13°, 0°, 13°, 26°, and 41° for the array antenna connected to it. Since the Rotman lens operates based on the true time delay principle, the operating frequency band of the lens is considered infinite under ideal conditions. However, the existence of an operating frequency band for the array antenna connected to the lens limits the frequency band in which the lens and antenna system can be efficiently utilized. The distance between array antenna elements is a parameter used in both the array antenna and lens design, and it is the main factor limiting the frequency band in which the system can be efficiently used. Within the scope of the study, two different Rotman lens designs have been developed. The lens data obtained from simulation and measurement results for both lenses have been utilized in plotting antenna array factors. The obtained antenna array factor graphs have been compared. Three different array antenna designs operating in the X-band were developed for use with a Rotman lens. To evaluate the lens performance with different types of antennas, array, series-fed Chebyshev array, and lotus array antenna designs were created. The designed antennas were connected to the lens, and the performance of the antenna and lens system was evaluated. It was observed that the measured and simulated data were consistent.