The Electromagnetic Field Very near to a Monopole

The near-zone field components 27πρ | Hϕ (ρ;z) |, 27πρ | E(ρz) | and 2(π/ß) | Ez(ρ;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 = π/2, Ω = 2 ln (2h/a) = 8.531, a/λ0 = 7.022 × 10-3, 1.01 ≤ ρρ;/a = 100, 0 ≤ z ρ h; (b) ßh = π,Ω = 9.917, 1.01 ≤ /a = 100, 0 ≤ z ≤h. Here ß = 2π/λ0 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.