有限平面上圆口径辐射场的数值分析

Numerical Analysis of Circular Aperture Antennas on Finite Planes

计算由TE1 1 模激励的圆波导末端开口所形成的圆口径天线的辐射场 .首先利用等效原理和矩量法计算嵌在无限大金属板上圆口径的等效磁流分布 ,允许圆波导中有任意多个高次模式存在 ,利用傅里叶变换法求得其辐射方向图 ,然后把该辐射场作为有限接地板边缘的入射场 ,利用几何绕射理论 (GTD)计算有限接地板对圆口径方向图的贡献 ,其中在焦散区及接近焦散区区域采用等效磁流法计算有限接地板的影响 ,给出计算公式及计算例子 。

The circular aperture antenna which is an open ended circular waveguide stimulated by TE 11 mode is analyzed. The method of moments is employed in conjunction with the equivalent source technique and the modal expansion theory to analyze the open ended circular waveguide. No restriction is imposed on the number of modes in the analysis. The problem of radiation from a circular aperture antenna embedded in an infinite ground plane is solved at first. Then expressions which represent the elevation plane patterns of the antenna embedded in a finite ground plane are derived using GTD(Geometrical Theory of Diffraction). The expressions for the field pattern are obtained by superposing the infinite ground plane solutions, the first order diffracted field solutions and the axial caustic solutions in their respective regions of validity.