Study Of VHF/UHF Broadband Omnidirectional Antennas And Its Array

Along with the rapid development of aerospace technology, long-distance rocket boost system has been updated very fast, which makes it possible to hit the communication satellite of the enemy accurately in future battlefield. Thus, it is possible to destroy the whole communication system in a short time. As a result, militaries of many countries have focused on the VHF/UHF band for long distance communication, and governments have put a lot of scientific research and funds into the VHF/UHF broadband omnidirectional antennas and its array, which makes the subject to be a much meaningful strategy research.Ultrashort broadband omnidirectional antenna and array can be applied not only to several types of sea and air military high-speed mobile platform, but also in various types of civilian communication platform. Therefore, it has the common research value in general.Firstly, the research background and significance of the VHF/UHF broadband omnidirectional antenna and array are described in this paper, including the development history, characteristics, significance and research status both home and abroad. Then the basic theory evolution of it was derived to explain the radiation theory of omnidirectional microstrip antenna and the theory of uniform circular antenna array.Secondly, three kinds of antennas, including the VHF/UHF wideband coupling monopole antenna, FM dipole antenna patch knife and ultrashort broadband dipole antenna are studied in this paper, which are widely used as the representative ultrashort(VHF / UHF) wideband omnidirectional antenna elements. These three VHF/UHF broadband omnidirectional antenna are actually done in the graduate project. They have good omnidirectional radiation, broadband and miniaturization characteristics in respect of electrical properties. Detailed theoretical analysis, research and overall optimization of parameters are discussed for each antenna unit. And upon the previous research, innovative improvements are achieved for the ultrashort broadband coupled monopole antenna, FM dipole antenna patch knife and ultrashort broadband dipole.Finally, the array of broadband VHF/UHF omnidirectional antenna is studied in this paper. Parameters of the ultrashort broadband symmetric uniform circle array are analyzed, and by feeding different phases and amplitudes to each element of the ultrashort broadband symmetrical ring antenna array, the beam pointing can be controlled flexibly and an omnidirectional scanning of 360° airspace can be achieved. And the beam scanning characteristics in the azimuth plane of the symmetrical broadband VHF/UHF time around even ring antenna array are studied and discussed in detail.