An Optimal Design of High-Gain Quasi-Cassegrain Antenna for Ultra-wideband Applications

In this manuscript, the design method for cassegrain antennas using geometrical optics is explained, and performance is analyzed. To reduce the axial dimension of the cassegrain antenna, it is suggested that the sub-reflector be replaced with a disk that is inexpensive and simple to make. The close proximity between the feed and sub-reflector has an impact on impedance matching, gain and bandwidth (BW). Computer simulation technology (CST) software is used to design and analyze the performance of the proposed antenna. The proposed antenna achieves a fractional bandwidth (FBW) of 57.14% from 7.5 - 13.5 GHz with an S
11
< - 16 dB over the band. The antenna has achieved the maximum gains of 43 dBi at 13.5 GHz, while the axial ratio (AR) is less than 1.3 dB over the frequency range. The simulated results demonstrated that the proposed antenna is a strong candidate for C and X-band circular polarization antennas with high aperture efficiency, low side-lobe level, and high gain performance.