圆波导硅探测结构对X波段电磁波模式的响应

采用数值模拟和理论分析方法,研究了圆波导内置n-Si探测结构对X波段几种常用电磁波模式的电场响应。首先基于强电场下的热载流子效应,设计了一种利用n-Si进行高功率脉冲实时测量的圆波导探测结构。接着采用三维并行电磁场时域有限差分方法,模拟研究并分析了TE11(两种极化方向)、TM01和TE01模式作用下圆波导探测结构内的横向电场分布特点。结果表明:不同模式下探测芯片内的横向电场均以径向电场为主,径向和角向电场幅度比约为10,而芯片在圆波导内引入的横向电场驻波比均不大于1.3。最后推导了圆波导探测结构在不同模式电场作用下的灵敏度表达式,理论分析指出了探测结构的最大承受功率与圆波导模式有关,最高可达422MW,响应时间则均为ps量级,初步证实了该探测结构可用于X波段百MW级脉冲波源在线探测的可行性。

Response of silicon detecting chip to X-band electromagnetic wave modes in circular waveguide

Electric field response of silicon detecting chip within circular waveguide to several usual electromagnetic wave modes in X-band is studied numerically and theoretically. Based on the hot carrier effect under high electric field, a silicon detecting structure is proposed to measure the high power microwave (HPM) pulse within circular waveguide in real time. Then cross-sectional electric field distributions are simulated and analyzed when HPMs with TE11 mode (with two orthogonal polarization directions), TM01 mode and TE01 mode are applied respectively by using the three dimensional parallel finite-difference time-domain (FDTD) method. Results of different modes show that the transverse electric fields are all dominated by radial components, and the amplitude ratios between radial and angular components are probably 10. The standing wave ratio of transverse electric field is no more than 1.3. At last, the sensitivities of the detecting structure for different modes in circular waveguide are derived. Theoretical analysis indicates that the maximum enduring power of the detecting structure, which can reach as high as 422 MW, is dependent upon modes, and its response time is in the picosecond-level. It attests the feasibility of on-line measurements of X-band HPM pulses employing the designed detecting structure