r✉ Bok Biz 其中B=2Re[H(k)]B=-2rRe[H(k)W] k=2时 H(2)=0 B2=月2=0 ∴H2(a)=0 2024/10/21 13( ) 1 0 1 1 2 2 2 1 2 cos k k k z H z z r k r z N   − − − +   − +     = 其中 ( ) 0 2Re  k =   H k   1 2 Re ( ) k k N  = − r H k W     k = 2 时 02 12   = = 0 ( ) 2  = 0 H z H (2 0 ) = 2024/10/21 13