Research On Miniaturized Microstrip Logarithmic Period Antenna

The Logarithmic Period Dipole Antenna(LPDA)is a kind of directional plate antenna that has wide bandwidth and is a high gain antenna.As an ultra-wideband antenna with simple structure,excellent performance and low cost,the antenna can obtain almost constant impedance,pattern and gain in a wide frequency band,and it has been widely used in short-wave,ultra-short wave and microwave bands.However,in the cases of size limitation,the application of LPDA is also limited.so the study on the miniaturization of LPDA is of great practical significance and application prospect.Since the advantages of light weight and high precision of the microstrip logarithmic period antenna(PLPDA),and the working principles of PLPDA and LPDA are similar.The paper analyzes the working principles and structures of LPDA and realizes the theoretical transition from LPDA to PLPDA.Firstly,a microstrip log-periodic antenna with a working range of 0.7-7GHz was designed according to the calculation and modification of LPDA parameters.Then,eight miniaturized logarithmic periodic antennas are designed by fractal of antenna oscillator,top-loading of oscillator and slotting of oscillator.These eight antennas have greatly improvements in the size of the structure compared to the logarithmic period antenna before miniaturization,the working bandwidth of the antennas has been increased in different degrees,and the lowest average gain of the antenna is about 5dBi.In this paper,we use HFSS15.0 to simulate and design nine logarithmic period antennas,and the arcuated logarithmic period antenna is processed and tested.The test results show that the bandwidth of the antenna is 0.7?8 GHz,and the average gain of the antenna is 5 dBi.Compared with the conventional microstrip logarithmic period antenna,the lateral size is reduced 50%and the vertical size is reduced 37.8%.