互易定理计算分层半空间上方任意取向偶极子的远区场

利用互易定理推导了考虑直达波和界面反射波时半空间分层界面上任意取向偶极子在上半空间远区辐射场的解析表达式. 进一步考虑电偶极子距离分界面为某一高度情形, 在考虑直达波和反射波程差基础上导出相应辐射场公式. 辐射场解析表达式中分层半空间TM和TE波反射系数可以通过连分数方法或传播矩阵法计算获得. 本文推导过程物理概念清晰, 所得解析结果适于计算观察点远离界面情形下偶极子的远区辐射场. 数值计算结果表明, 利用本文结果可以快速分析半空间上方任意取向偶极子的远区辐射场.

Calculating far field of an arbitrarily oriented electric dipole located above layered half space using reciprocity theorem

Based on the reciprocity theorem, the far field formulation of an arbitrarily oriented electric dipole located at the interface of the layered half space is deduced. Then, considering the optical path difference between directed wave and reflected wave, the formula of the electric dipole located above the interface of the layered half space is discussed. The TE and the TM reflection coefficients of the layered half space can be calculated by the propagation matrix method or the continued fraction method. The presente method, in which the deduction process possesses concise physics concept, is suitable for calculating the radiated field of an electric dipole when the observation point is away from the interface. The numerical results show that using our method the far radiation field of an arbitrarily oriented electric dipole located above the interface of layered half space can be guickly analyzed.