Design and Fabrication of a Novel Ultrawideband Combined Antenna

In this letter, design and fabrication of an ultrawideband combined antenna are presented. Actually, this element is a combination of a TEM horn antenna and some magnetic dipoles. The combination of radiation fields due to these elements causes reduction in reactive energy around the antenna, and with this method, the antenna matching in a wide frequency band becomes possible. The bandwidth is further improved by tapering the radiation part of the antenna exponentially. Also, proposing a novel transition structure from coaxial cable to the antenna, the discontinuity the wave faces is reduced and, finally, a bandwidth of 180 MHz-30 GHz is obtained for this structure. The fabrication results for this antenna verify simulation results. The plots of return loss and radiation pattern at several frequencies will be presented. Finite integral-based CST software is utilized for simulation.