Field and Wave Electromagnetics 2nd Edition by David Cheng

Exercise 13

A small filamentary rectangular loop of dimensions L x and L y lies in the xy -plane with its center at the origin and sides parallel to the x - and y -axes. The loop carries a current i(t) = I 0 cos t. Assuming L x and L y to be much less than the wavelength, find the instan­taneous expressions for the following quantities at a point in the far zone:
a) vector magnetic potential A ,
b) electric field intensity E ,
c) magnetic field intensity H.
Compare the results in parts (b) and (c) with Eqs. (11-30a) and (11 -30b), respectively.