矩形波导开口与缝隙辐射的FDTD分析

时域有限差分方法在分析波导辐射问题时具有非常大的灵活性,从Gauss脉冲在波导中的加入和传输出发,给出了计算模型,讨论了激励信号参数的选取以及信号在波导中的高保真传输;计算了脉冲激励条件下开口波导的辐射场,与测量结果一致,表明该方法的有效性。计算结果还表明Kirchhoff近似对口径面场分布的估计沿短边方向有较大偏差。最后给出了采用文中方法对一个四元波导缝隙阵列和喇叭天线辐射的计算实例。

Analysis of Open Waveguide and Slotted Antenna Radiation Using FDTD Method

Using the finite-difference time-domain(FDTD)method to analyze the radiation of an open waveguide demonstrates high flexibility.The fidelity of excited signal can be guaranteed under the condition that some parameters of modulated Gaussian pulse be properly selected,and the corresponding computation model is given.The calculated radiating field of an open waveguide excited by modulated Gaussian pulse agrees with the measured result,which shows the validity of proposed method.The result also illustrates the discrepancies of the field distribution in the aperture along shorter side when the Kirchhoff's approximation is used.Finally,two more examples of the radiation by slotted array and horn antenna are given.