Design And Study Of Broadband Miniaturized Antennas

As the rapid development of science and technology, the expanding market of wireless communication makes harsher and harsher demands for electronic equipment. As the key part of a wireless system to transmit and receive signals, the broadband and miniaturization design of the antenna is obviously an important trend. In this paper, two classical antennas-helical antenna and conical monopole antenna are discussed and well-designed for miniaturization and broadband performance.The main work can be summarized as follows:1. A broadband circularly-polarized conical helical antenna with a tapered strip shaped arm is proposed. After optimizing the height and width of the tapered strip, this helical antenna can finally provide a circularly-polarized operation bandwidth of nearly60%, an axial gain of more than8dBi, and a small electrical size of0.45λ×0.45λ×0.45λ. Then a specific helix model is fabricated by using the3D printing technology and is also preliminarily tested.2. For the proposed conical helical antenna with a tapered strip, we use the dielectric loading technique to realize its miniaturization and broadband circularly-polarized design. After discussing the impacts of different loading ways on the antenna dimensions and circular polarization performance, we finally confirm that the mixed dielectric loading technique can make the helical antenna realize miniaturization with an electrical size of0.255λ×0.255λ×0.325λ and maintain broadband axial mode circularly-polarized characteristics with an effective bandwidth of about40%.3. On the basis of the conical monopole antenna, an omnidirectional single-polarized ceiling-mounted antenna for the2G/3G/4G mobile indoor communication system is designed by introducing transition structures and parasitic elements, which has the dimensions of130mm×130mm×59mm.