Design And Test Of A New High Symmetry Pattern Loop Ante Nna

Ripple test is an important way to evaluate the performance of the anechoic chamber quiet zone.Multi-probe anechoic chamber calibration is the basic requirement for ensuring reliable wireless terminal over the air(OTA)test results.The traditional ripple test and multi-probe anechoic chamber calibration can be performed using only the standard dipole antenna,but the met hod of multiplexing this single polarized antenna is very complicated,and the accuracy and reliability of the test and calibration results are hard to be guaranteed.The use of a linear feed loop antenna can effectively reduce the ripple test and the comple xity of the multi-probe anechoic chamber calibration.However,this loop antenna has a large size and cannot be fully applied to small and medium size measurement systems.Ripple test and multi-probe anechoic chamber calibration are significantly influenced by the size of the calibration antenna.The key to improving the accuracy and reliability of the anechoic chamber ripple test and the multi-probe anechoic chamber calibration is to reduce the size of the calibration antenna,but the miniaturized of the calibration antenna is problem that has not yet been solving nowadays.Therefore,it is very important to study the novel loop antenna with a small profile and high symmetry to improve the anechoic chamber ripple test and the accuracy of the multi-probe anechoic chamber calibration.In order to solve the above problems,based on Alford loop antenna and balun design principle,this thesis proposes a standard loop antenna miniaturization design method.The main research contents include the following parts:1.Introduce the principle of antenna radiation and antenna parameters,derives the current element,magnetic element and circular loop with uniform current radiation equation,explain the application of standard loop antenna in ripple test and multi-probe anechoic chamber calibration,analyze the shortcomings of the standard loop antenna,point out the technical difficulties in the miniaturization of the standard loop antenna,and gives the significance of designing a new type of high symmetry circular antenna and the requirement of the antenna performance index.2.A high symmetry linear feed loop antenna is proposed.The antenna is designed by Alford antenna design principle,with simple structure and low cost,whose radiation characteristics is meet the Cellular Telecommunications and Internet Association(CTIA)calibration antenna requirements,can be used for large scale anechoic chamber ripple test and multi-probe anechoic chamber calibration,but there is a problem that the antenna size is too large,wh ich affects the accuracy and reliability of the ripple test and the chamber calibration result,and is not fully applicable to small and medium sized measurement systems.3.Proposed a new type of high symmetry loop antenna,innovatively combine the Archimedes spiral and the broadband tapered balun to ensure the antenna meets requirements of the CTIA calibration antenna,while reducing the size of the linear feed loop antenna,meanwhile,the farthest apparent phase center point is about 0.3 mm from the geometric center,which is almost coincident with the geometric center.The good agreement between the measured results and simulated results verifies the effectiveness of this design method.In summary,this thesis presents a design method of a high symmetry linear feed loop antenna,which effectively solves the problem that the single polarized antenna is too complicated to be used in the ripple test and multi-probe anechoic chamber calibration;and proposes a new type of high symmetry loop antenna,which effectively solves the problem of size of the linear feed loop antenna.