Research On X/Ka/W-Band Exposure System For Microwave Biological Effect Experiments

With the development of wireless systems in military and civilian fields such as radar and communication,human beings live in a more complex electromagnetic(EM)wave environment.The effects of EM waves on humans and other living things are becoming more and more important.Based on microwave biological effect,this thesis studies and designs the exposure systems in X,Ka and W Bands.The exposure systems include hardware systems such as frequency generation,multiplier,amplifier and radiators.This thesis provides suitable electromagnetic exposure sources and complete radiation dosimetry datas for biological experiments.The following is completed in this thesis:Firstly,the basic parameters and research methods of experimental subjects under the background of biological effects of EM radiation are determined.In the frequency bands and experimental environment of the study,the basic parameters of biological samples are analyzed.The EM simulation method suitable for this study is determined with reference to the dosimetry evaluation standards.Then,the system architectures of the three bands are proposed.Secondly,the circuits of the exposure systems in three bands are designed,including the design of microwave passive circuit,application of RF MMIC,DC power supply and design of cavity.The signal generated by the frequency source is multiplied and amplified in the subsequent stage to reach the target output frequency and power.In addition,microwave passive structures such as filters and microstrip-waveguide transition structures are designed.The above designs realize a clean frequency spectrum output in each band without interference such as clutters and harmonics.Finally,the RF circuits of the three bands are tested.The required frequency and power can be achieved.Through EM numerical simulation,the radiation dosimetry distributions of the three band radiator systems are given,including and power density(PD)and the specific absorption rate(SAR).In the X,Ka and W bands,the mean values of SAR in the cell layer are 41.6 W/kg,36.6 W/kg and 59.6 W/kg respectively,with relative standard deviations of 36.3%,15.6%and 18.0%.And the power density ranges are 30 mW/cm~2-50 mW/cm~2,6 mW/cm~2-12 mW/cm~2 and 7 mW/cm~2-14 mW/cm~2respectively.In the Ka and W-bands,24-well culture dishes can be used for the controlled experiments of different gradient radiation dosimetry or different biological cells.The exposure systems of the three bands in this thesis can meet the basic requirements of biological experiments,which is the foundation for subsequent biological experiments.