A Waveguide Slot Array antenna design for X-band radar

In this paper, it is aimed to design and optimize a Waveguide Slotted Array (WSA) antennas for X-band radar applications. The slot offsets, slot lengths and widths, port position of the antenna are optimized by using Trust Region Framework and Classic Powel algorithms in simulation environment without requiring analytical calculations. The side lobes of radiation pattern are suppressed by using these optimizations. The antennas are simulated with different slot's numbers (11 and 21 slotted antennas). Although using more slots provides narrower beam, back lobe of the radiation pattern rises crucial levels. A parabolic structure is designed to avoid from back lobes and a small gain increment can be obtained with this modification. The modified 21-slotted WSA antenna presents 20.8 dB maximum realized gain, 4.50 degree 3 dB angular width, 90 degree main lobe direction, and 24.9 dB side lobe level in simulation results at 9.5 GHz. The antenna is also fabricated and measured. A good agreement is obtained between simulation and measurement.