说明：  无线通信经典教材（杨鸿文译）（美）（Goldsmith,A.）著 课后答案英文版，我就看不上某些网站要积分的德行，专门去找了份答案分享在这。需要的自己下载哦
(Wireless communication classic textbook (translated by Yang Hongwen) (US) (Goldsmith, A.) After the English version of the class answer, I don't look at the virtues of some websites to score points, specifically went to find an answer to share here. Need to download it yourself)