Ka-band Gtem Cell Research

With the electrical technology developments, the electromagnetic wave has been widely applied. So the living environment is full of electromagnetic wave now. It is very urgent to do quantitative research on the influence which the electromagnetic wave impact on organism. The Gigahertz Transverse Electro Magnetic cell(GTEM Cell) has the advantage:wide working frequency band and it is convenient to apply. The GTEM Cell is able to produce uniform electromagnetic field owing to the urgency. So the GTEM Cell is able to meet the bioelectromagnetic experiment application well.The development of the GTEM Cell is firstly introduced in this paper. After that, we focus on the calculation of the characteristic impedance of the GTEM Cell transition. A GTEM Cell transition is designed in this paper and it has the following advantages:simple structure, wide applicable frequency band, low insertion loss. The characteristic impedance of the main part of the GTEM Cell is calculated with a new simple and effective method, and then the size of the main part of the GTEM Cell is decided. The optimized design of the characteristic impedance of the main part of the GTEM Cell is simulated by the CST which is based on the finite integration. The transmission performance of the GTEM Cell is improved by the optimal design. The upper limit frequency of the Ka band GTEM Cell proposed in this paper is40GHz. The measured return loss S11of the GTEM Cell is about-10dB between30GHz-40GHz and the S11is20.228dB at35GHz. The test area of the GTEM Cell is about2.97*3.49cm2. Then the two kinds order modes which are "basic" mode and "non-basic" mode in the GTEM Cell is analyzed, and the current distribution of the septum inside the GTEM Cell is analyzed afterwards. When the volume of the GTEM Cell is double, the uniform fields will still wide enough to satisfy the application by suppressed high TE modes with narrow slot on the septum. It provides a method to solve the contradiction between the upper limit frequency and the volume of the GTEM Cell. Biological non-thermal effect and the mechanism interaction between the electromagnetic wave and the organism are presented in section four. Finally, we do an experiment with the millimeter wave radiation experiment platform which consists of the GTEM Cell designed in the thesis to research the biological non-thermal effect of the rice seeds. Through the experiment the biological non-thermal effect is exist. And the germination percentage of the rice seeds is suppressed because of the millimeter wave radiation.