Design Of Broadband Electromagnetic Radiation Cavity And Built-in Electromagnetic Field Probe Antenna

As a significant part of ever increasing environmental pollution, electromagnetic radiation has caused lots of experts and scholars’ attention. The impact of the electromagnetic radiation with different frequency and intensity of the human body remains a problem with keen interests. However, the current research mainly focuses on industry frequency and mobile communication frequencies, with little attention to the wideband frequency electromagnetic radiation’s influence on human vivo cells.In this thesis, two important parts of the experimental electromagnetic system which are the electromagnetic radiation cavity and the electromagnetic field probe antenna are studied and designed. As the radiation device of the electromagnetic field,it is required that the electromagnetic radiation cavity has good transmission performance in a wide frequency band.For the electromagnetic field probe antenna,it is required that it has the smaller size,and it is also has the characteristics of good isotropic, good frequency response and good linearity.Coaxial discontinuity theory is adopted as the theoretical support for the wide frequency band electromagnetic radiation cavity,and it is also used Ansoft HFSS software as the auxiliary tool for the optimization design,then the parts which may exist coaxial discontinuity are compensated,finally the electromagnetic radiation cavity with tapered transition section is designed,and it has the good transmission performance in wide frequency band. The simulated results and measured results have good consistency,Return loss can be less than10dB within0to3GHz. Electric field probe antenna is designed based on dipole antenna which is fed by coplanar waveguide with ground(GCPW).In order to increase its usable frequency and suppress spurious mode,some short pins are placed between the upper ground and the lower ground of the GCPW.Magnetic field probe is also designed based on loop antenna which is fed by GCPW.In order to increase its usable frequency and suppress spurious mode,some short pins also are placed between the upper ground and the lower ground of the GCPW and the quasi slot structure are reloaded on the feedline.Three electric field antenna and three magnetic field are combined together to constitute the three-dimensional electric field antenna and the magnetic field antenna to ensure its isotropic features, which is rarely decribed in the related papers.The simulated results and measured results show that the available frequency of three dimensional electric field probe antenna and magnetic field probe antenna can be up to8.5GHz, and it is also of good frequency response characteristics.Finally, electromagnetic radiation cavity and electromagnetic field probe antenna has been carried out the joint simulation and measurement.Simulated results and measured results demonstrate that it has good performance when they are implemented together and the transmission factor ranges from-20dB to-60dB.