Design Of The Printed Plane LPDA Antenna In The UHF Band

With the further research on broadband communication and radio technology,The developmentof the communication system has been paid much concern and more attention by theresearchers,Especially for the antennas which have characteristic of a miniaturized, wide-band,high-gain as a communication terminal. And yet the planted planar antennas have widely used in thewireless communication industry because of its production of high precision, consistency and easeof loading.The antenna is designed in this paper which is based on the analysis of the theory of PrintedPlanar antenna and Log-Periodic Dipole Antenna(LPDA).this paper design a T type of printedplanar (LPDA) about a relatively small,wide bandwidth and high gain with the help of IE3Delectromagnetic simulation software, then process the antenna. And the actual test results have goodaccordance with the data of simulated. It demonstrate that the antenna is useful, then this paperdesign a Knuckle-type of printed planar LPDA which have a characteristics wideband and high gain.and because of each oscillator of the antenna are bent into Knuckle-type, the overall size of theantenna is relatively smaller, further reducing the transverse dimensions of the antenna. Thisantenna is more suitable for as a terminal device for the field of television and radiocommunication.This paper mainly divided into the following steps:Firstly, start with the analysis on various component of the printed planar LPDA，it is describedabout the structure and working principle of the LPDA in detail, and analyze the LPDA with themethod of moment(MOM).meanwhile，it is analyzed and introduced on miniaturization andbroadband technology for the broadband antenna which can lay good theoretical basis for aminiaturized printed planar LPDA.Secondly, based on the discussion on the miniaturization and broadband technologies of theantenna. The characteristic of broadband can be obtained with making use of the model of LPDA, itcan be introduced top loading to achieve miniaturization of the antenna, and design a T-type ofprinted planar LPDA in the470MHz-862MHz.compare with the traditional printed planar LPDA,the antenna is reduced about only lateral dimension with top loading to longest oscillator. Thenprocess the antenna.Finally, it is designed that Knuckle type printed planar LPDA, which have the characteristics of a relatively, miniaturization, wideband and high gain. The operating frequency is470MHz-862MHz,belong to the Ultra High Frequency（UHF),each oscillator of the antenna h ave been folded into knuckle.Then it can be analyzed and discussed on voltage standing wave ration(VSWR), Return Loss(S11),radiation pattern. And compare to the antenna that not be loaded.At last, process the antenna and test. By experiments, test data and simulationdata are in good agreement. The electrical characteristics of the antenna is well positionedto meet the requirement. Thus the antenna has great practical value in the UHF wide-bandsystem.