Design Of Low Profile And Ultra-wideband Electrically Small Antenna

With the development of science and technology, the radio spectrum continues to expand, and the bandwidth of the radio system also continues to be broadened, which promotes the birth of a new subject-UWB electromagnetics in the end of twentieth Century. As an indispensable part of the radio system, the ultra wideband antenna has become a research spot in recent years. The VHF/UHF bands are two important bands of the wireless communication, and the miniaturization and broadband of the antenna operating in these bands are essential for the loading of vehicles, aircrafts, warships. Under the background of communications on vehicles, we discussed the broadband and miniaturization of the antenna in the VHF/UHF bands, and some works have been done as follows:1. The performance characteristics and main applications of VHF and UHF band antennas have been introduced.2. By the study of various types of three-dimensional antennas, such as disk cone antenna, conical antenna, and horn antenna, some techniques of frequency broadening for antennas have been introduced, including the gradual structure, parasitic ring resonator, short pins and resistive loading. Consequently, an ultra-wide band operating in 30-600MHz has been designed finally, also based on some techniques of antenna miniaturization.3. The investigation of planer ultra-wide band antenna has been discussed in the 3 section. By planarizing the cone antenna designed in the 2 section, a planer ultra-wide band antenna working in a frequency band of 30-600MHz has been designed, which has a much lower profile and lead to more application scenarios.The symmetrical design of the planar antenna is carried out, which further improves the performance of the antenna.4. We have introduced the fabrication and testing of the designed antennas in VHF/UHF bans. Ultimately, we have summarized the advantages and limitations of the designed antenna, as well as the prospects of applications.