การออกแบบสายอากาศแถวลำดับแบบคงรูปย่านความถี่ S-band สำหรับ ระบบเรดาร์ตรวจจับวัตถุแปลกปลอม

Abstract

The antenna design for the Synthetic aperture radar system to detect foreign object debris in the S-band frequency (2.45 GHz) was the purpose of this research. The proposed antenna was based on a conformal antenna array consisting of conformal antenna elements, which provides wide beamwidth characteristics. Consequently, the array gives a constant gain property, with a maximum gain difference of less than 3 dB and it had high directional accuracy when switching the antenna beam. The proposed antenna was designed as a suspended structure utilizing the Minkowski fractal loop to reduce the size of the elements. These elements could be arranged in an array with a spacing of 0.50λ. Each element in the array is referred to as a Minkowski Fractal Suspended Conformal Patch Antenna, or MKF-SCPA. The measured results of a single element showed a gain of 7.10 dBi with a beamwidth in the H-plane and E-plane were 90 and 62 deg, respectively. The single element was arranged in a conformal phased array with a curved array radius of 2.00λ and a size of 4X4 elements, called the MKF-SCPA Conformal phased array. The measured results were in good agreement with the simulation. The antenna prototype provides a maximum gain of 15.12 dBi. The difference in the maximum gain when switching the beam to the desired direction was 0.92 dB, indicating a constant gain property. Furthermore, it provides high directional accuracy with a beam-pointing error of 2.22%. Therefore, the antenna prototype is appropriate for use in the synthetic aperture radar system to detect foreign object debris.