Question

Question 27 1 pts Determine the total shielding effectiveness S, in dB, of an aluminum shield of thickness 0.01 cm at f= 100 kHz, for a source in the far field. Use a total conductivity of sigma = 3.8 x 107 (S/m) and a permeability of mu = 4pi x 10-7 (H/m) for aluminum. 116 dB 118 dB 120 dB 122 dB Question 28 1 pts A steel shield has total conductivity of sigma = 5.8 x 10 (S/m) and a permeability of mu = 4pi x 10-4 (H/m). What is the relative conductivity and relative permeability of this material? or 0.1, flip 1000 0, = 0.1, Mop = 10,000 O 0r = 0.01, Hip = 1000 OOT 0.001, flip = 10,000

Answer 1

Que (27 shielding Effectiveness in dB S.E. no tls 20log +20 ung loge SE 1) R(dB) + A (dB) S = JiTfuo 1 x 100X103 x 40 xro7X 3.8x107 6a 2.58 xlo-4 m A = 8.7 Hle) 8.7 X * 0.01x10-2 9-68 x 10-4 " ) A - 3.37 dB. souter poco n Il at fu 291 X 100x103 X400X1007 3.8x107 1.44 xlory So R = no 20 log 116.60 ung so SE = A +R = 3.37 +116.60 > 119.97 dB SE î 120 dB option(