Application of the FDTD method to the analysis of biconical antennas

An accurate prediction of the radiation pattern from a biconical antenna is obtained using the finite difference time domain (FDTD) numerical method. It is shown that a major advantage of the FDTD method is the ability to analyze antenna patterns over a wide frequency bandwidth from a single time domain simulation. Such information regarding biconical antennas is not otherwise easily obtained. Although many antenna textbooks discuss antenna patterns for extreme cases such as the infinite biconical antenna or biconical antennas with small cone angles, antenna patterns for biconic antennas with half-angles in the range 0/spl deg//spl Lt//spl psi/<90/spl deg/ cone angles, are hard to find. In this paper, the antenna patterns, calculated using the FDTD method, are validated by a comparison to measurements. The effect of a broad bandwidth RF choke to reduce the sidelobes is also analyzed using the FDTD method and compared to measurements.