Source: http://chiataimakro.vicp.cc:8880/%E5%BE%85%E6%95%B4%E7%90%86/%E7%94%B5%E6%B3%A2%E3%80%81%E7%94%B5%E7%A3%81/Theory%20of%20Electromagnetic%20Wave%20Propagation%20-%20Charles%20Herach%20Papas.pdf