Analyze And Design Loop Antenna For Small Anechoic Chamber Calibration

With the rapid development of wireless communication technologies,wireless devices becoming increasingly popular,the test of radiation performance for wireless device gets more and more attention in manufacturers and operators as well.In the past,the wireless performance test of wireless devices only focused on independently tested antenna performance and the RF performance of wireless devices in cable connection mode,It ignored the whole machine performance of wireless devices and did not accurately reflect the real situation of wireless devices.Therefore,OTA test of radiation performance of equipment,Therefore,an OTA test focused on the whole machine performance of the test equipment was proposed.The CTIA standard requires that the OTA test should be performed in an anechoic chamber,in order to ensure the accuracy of the measurement,the performance of the measurement site must be strictly checked,Usually,it is necessary to calibrate the error and loss of anechoic chamber,test antenna,cable before OTA test,in order to greatly reduce the error in the antenna measurement,it is necessary to use a calibration antenna with good roundness.The probe antenna of anechoic chamber are dual polarized antenna,so the calibration requires a vertical polarization calibration antenna,also requires a horizontal polarization calibration antenna,based on this background,this paper designs a ternary "beveled" dipole element combined loop antenna with good roundness,the main work of this paper is as follows:(1)Combined with the relevant literature,analyze the fundamental structure.radiation mechanism and design method of multi-dipole-element combined loop antenna in detail and design a six-dipole element combined loop antenna,the influence of the parameters of the antenna on the Electrical performance and radiation performance of the antenna is analyzed by the HFSS software,including the resonant frequency,S11 and the roundness of the pattern on the azimuth plane.(2)The roundness perforrmance of the simple ternary combined loop antenna is studied,the influence of the coupling structure and the "beveled" dipole structure on the roundness of the ternary combined loop antenna is analyzed,the impedance matching design of the radiating element is carried out,various methods to enhance the bandwidth of the antenna are discussed,and a ternary "beveled" dipole element loop antenna is designed.(3)On the basis of simulation analysis,the electrical performance and radiation performance of the antenna are tested.The practical measurement results show that the resonant frequency of the antenna is 2.35GHz,the bandwidth of S11<-10dB is 9.3%,and the roundness of the highest frequency in the frequency band is 0.21dB,basically in line with the design indicators.