The Design Of Sensing Antennas For Multi-Radiator Electric Field Measurement

With the development of mobile communication system and the construction of civil radar launcher,the problem of EMR and EMI has become increasingly serious.Monitoring of EMR and EMI from mobile communication base stations,Wi Fi and radar is an important guarantee for the normal operation of mobile communication systems and radar,as well as a necessary means to ensure the safety of electromagnetic environment.Simple and accurate measurement methods and instruments are required for EMR measurement to determine whether the detected areas meet the relevant standards.In this paper,the core component of the monitoring equipment is studied.The electric field measurement antennas are designed,which meet the requirements of the special-purpose for measuring the EMR and EMI of mobile communication system and radar,multi-band and broadband,sensitivity,isotropy and portability.The work of the paper is as follow: 1.Two almost omnidirectional 2G,3G and 4G mobile communication system electric field sensing antennas are designed to three symmetrical dipoles array antennas by using the omnidirectional characteristics of symmetric dipole.It effectively reduces the size of electric field sensing antenna by multi-Layer PCB technology which are made of Die Lectric Buried antennas and loading folded branch technology.The sizes are 72.0 mm?48.0 mm?6.0 mm and 56.0 mm?50.0 mm?5.6 mm.The bands that return loss less than-6 d B are 0.85 GHz-0.95 GHz,1.67 GHz-2.74 GHz and 0.86 GHz-0.96 GHz,1.70 GHz-3.50 GHz.2.A multi-band almost omnidirectional Wi Fi electric field sensing antenna is designed to two symmetry dipoles array antennas.The oscillator changes to a triangular structure to reduce the bandwidth of the antenna.The size is 35.0 mm?35.0 mm?1.6 mm.The bands that return loss less than-10 d B are 2.39 GHz-2.50 GHz and 5.13 GHz-5.81 GHz.3.S band and C band radar electric field measurement sensing antennas are designed to two symmetry dipoles array antennas which are broadband and almost omnidirectional.After simulation and optimization,S band and C band radar electric field measurement antennas basically cover S band and C band respectivly.The sizes are 50.0 mm?36.0 mm?1.6 mm and 30.0 mm?24.0 mm?1.0 mm.The bands that return loss less than-10 d B are 2.21 GHz-4.05 GHz and 3.90 GHz-7.90 GHz.4.The above electric field measurement sensor antenna is fabricated and the return loss and radiation pattern are tested.The results show that these electric field measuring sensor antennas can meet the requirements of the special-purpose for measuring mobile communication and radar specificity,multiband or broadband,sensitivity and portability,basically satisfying isotropic requirements.The antenna coefficient and linearity of the 2G band of the electric field sensing antenna in the mobile communication band are measured by the standard antenna method(SAM).The antenna coefficient of other antennas has not been measured due to laboratory's conditions.The electric field measurement antenna designed in this paper can measure the EMR and EMI of mobile communication system and S band and C band radar with the use of portable spectrum analyzer.