Question

Please be neat and show all work, thank you.

Small antennas have low efficiencies (as will be seen in Chapter 14 and the efficiency increases with size up to the point at which a critia dimension of the antenna is an appreciable fraction of a wavelength s N8. (a) An antenna that is 12 cm long is operated in air at 1 MHz. Wh fraction of a wavelength long is it? (b) The same antenna is embedded 11.4 2000. What fraction of a 20 and u,= in a ferrite material for which e,= wavelength is it now?

Answer 1

il L in air 300m 2 0.12 m First it is operated in air freq= IMH2 = so a c=&f 3x108. 1x 10$x xz 300 m antenna is 12 cm long so antenna length a deo portalu =) doo in ferrite material c is changed and will be u and u 3x10% = 3x108 20x2000 ooxa V21.5X106 so Kalf z) x v do 1.5X1039 Az 1.5 m no e basse 0.18 or otte 2 3 x 10 Ar Er 5x10 06 ho 2 0.18 2 612 0-16 .