Suppression of Sidelobes Level for Parabolic Reflector Antennas

In recent years, different researches have been done in the context of the sidelobe level suppression for the military and civilian porposes. In these studies, various methods have been considered to reduce the sidelobe level, such as: edging the antenna in different cases, surface impedance tuning, placing metal pills on the reflector surface, placing resonant and non-resonant elements on the edges around the antenna. In this article, the effect of focal length and diameter of parabolic reflector antenna on the suppression of the sidelobe level has been investigated and obtained by optimization without the use of complex and costly structures. Depending on the need for the maximum gain, the small size or the minimum sidelobe level, the antenna can be designed. According to the purpose of the minimum sidelobe level, the proposed antenna has a working frequency of 12.5GHz, gain of 39.07dBi, 4.967λ (11.9 Cm) depth, 39.24λ (94.11 Cm) diameter, 19.375λ (46.47 Cm) focal length, -44.91dB and -43.5dB Sidelobe level in E and H-Plane respectively. This antenna has sidelobe levels of -30.76 and -47.15 at frequencies of 6.5 and 18.5GHz.