The Electromagnetic Field Very near to a Monopole

The near-zone field components 27¿¿ | H¿ (¿;z) |, 27¿¿ | E¿(¿;z) | and 2(¿/ß) | Ez(¿;z) | are determined numerically for a monopole of length h and radius a erected vertically over a perfectly conducting half-space of infinite extent. Curves are supplied for the field under the following conditions: (a) ßh = ¿/2, ¿ = 2 ln (2h/a) = 8.531, a/¿0 = 7.022 × 10-3, 1.01 ¿ ¿/a ¿ 100, 0 ¿ z ¿ h; (b) ßh = ¿,¿ = 9.917, 1.01 ¿ ¿/a = 100, 0 ¿ z ¿ h. Here ß = 2¿/¿0 is the free-space propagation constant. Unit voltage is applied to the base of the monopole by means of a coaxial cable having a characteristic impedance of Zc = 50 ohms.