Research On The Technology Of Miniaturized Antennas

With the development of the electronic communications in recent years,the requirement of the miniaturized antenna is becoming higher and higher.The microstrip antennas have the advantages of light-weight,low profile,low cost and easy to conformal with other objects,which have been widely used in wireless communication.Therefore,miniaturization of microstrip antennas has become a research hotspot.This article focuses on the miniaturization technology of the microstrip antennas.First,we research on the miniaturization,multi-frequency,reconfigurable and other technologies of the microstrip antennas.After that,we have designed three miniaturized microstrip antennas with different structures.The main work of this paper are as follow.Firstly,a coplanar waveguide fed dual-frequency circular annular slot antenna is designed.The miniaturization and dual-band characteristic of the antenna is achieved by adding a semi-closed ring conductor strip structure in the annular slot antenna.The antenna is small size and low cost.The operating frequency of the antenna is 2.42GHz-2.48GHz and5.50GHz-5.91GHz.The overall size of the antenna is only0.176?₀?0.176?₀?0.012?₀,and the outer diameter of the annular is only 16mm,which shows the miniaturization characteristic.Then,we use simulation software to analyze the effect of ground plane size on antenna radiation performance.The slot antenna was processed,and the test results have good agreement with the simulations.Secondly,a miniaturized circularly polarized microstrip antenna is designed.The antenna use a stacked structure,the miniaturization of the antenna is achieved by using shorting pins and loading rectangular slot rings?Compared to the reference antenna,the lowest resonant frequency of this antenna is reduced by 39 percent?Circular polarization of the antenna is realized by adjusting the length of the rectangular slot rings.Under the size of0.32?₀?0.32?₀?0.03?₀,the operating frequency is 2.69GHz-2.78 GHz,and the maximum gain in the operating band of the antenna reaches 5.0 dB.Finally,a miniaturized frequency and polarization reconfigurable antenna is designed.The antenna operating frequency is reduced by loading ring slot and six rectangular slots on the ground plane.PIN diodes are added at the connections between the six rectangular slots and the ring slot.By controlling the state of each diode,it is possible to control whether or not the annular gap and the different rectangular gaps are connected,so as to realize the switching of the operation modes of the antenna.The proposed antenna has six different operation status including linear polarization at the center frequency of 1.9GHz,2.1GHz,2.4GHz and 2.6GHz,right-hand circular polarization and left-hand circular polarization at the center frequency of 2.4GHz.Besides,we have also extended the research on the mechanical reconfigurability of the antenna.We designed a medium tray structure printed with a metal circular arc,and the tray is cling to the ground plane of the antenna.By rotating the tray,we can mechanically control the opening and closing between the six rectangular slots and the ring slot.Thus,we can make the antenna realized not only the mechanical reconfigurability characteristic but also the electronically reconfigurability characteristic,and both of these antennas have been processed and measured.