부산대학교 도서관

This paper presents an ultra-wideband multibeam antenna with eight radiating elements that are connected to the central cylindrical part. Each radiating element consists of a TEM horn fed by a coaxial to ridged planar waveguide transition. The connection between the radiating elements and the central cylindrical part equivalently acts as a biconical antenna. The ultra-wideband behavior of the antenna is guaranteed by the wideband properties TEM horn and coaxial to ridged planar waveguide adapter. Comprehensive optimization is performed to minimize the return losses and cross-coupling between ports to reach appropriate performance. A prototype of the antenna is fabricated to use in the experimental verification. An adequate level of agreement observes between the measurement and simulation results. Comparing results confirms that the proposed antenna has proper performance at the frequency band of 2–18 GHz. The proposed antenna has a diameter and height of $9.5 \lambda _{0} \times 1.33 \lambda _{0}$ , and its dimensions, especially the structure’s height, are smaller than the previous investigations. Also, the measurement gain of the proposed antenna changes from 7 to 15.7 dBi in the antenna’s frequency range and has an isolation range between −20 to −70 dB. Another advantage of this antenna is its low losses and high-power handling due to its all-metallic structure. These features make this antenna a suitable choice for high-power applications.