Research On The Miniaturization Of UHF Band Antenna And Its Application On Board

The electromagnetic wave of UHF band has lower free-space loss and stronger diffraction performance,so it is widely used in long-distance communication systems.The traditional UHF band antennas usually have a large physical size and are difficult to meet the application requirements on a small carrier.With the development of material technology and integrated chip technology,miniaturization and integration techniques have become important development directions of UHF antennas.In this paper,a series of theoretical researches and engineering applications are carried out on the miniaturization of UHF antennas based on the needs of the subject.The main contents are as follows:In the first part,this article focuses on the miniaturization techniques of antennas.And on this basis,multi-band technology evolution is presented.In the second part,the crossed dipoles using artificial magnetic conductor is studied,and the influence of different reflecting plates on the performance of crossed dipoles is researched.On this basis,a novel cross-slotted patch type AMC structure is proposed and applied to the folded crossed dipoles.The influence of the cross slots on the antenna impedance matching and the circular polarization performance is analyzed with the equivalent circuit of the whole antenna.In the third part,the miniaturized quadrifilar helix antenna is studyed.First of all,combined with the basic principle of the quadrifilar helix antenna,a prototype small antenna antenna is designed by loading the dielectric rod and increasing the rotation angle.Then,an improved dual-band antenna used multi-resonance branch technology is proposed.The improved antenna is fabricated,and the measured results show good agreement with the simulated.The designed antenna exhibits great radiation performance in the B3 and L1 band.In the fourth part,miniaturized active antennas in missile are designed.In order to meet the requirements of high integration and electromagnetic compatibility in design of antennas and radio frequency circuits for the wireless communication system in missile,a small-size circularly polarized microstrip antenna and a low-noise amplifier circuit are designed as the receiving active antenna,and a small-sized barrel monopole antenna and a power amplifier circuit are designed as a transmitting active antenna.