Phase change on transmission of microwaves through metal disc delay dielectrics
Expressions for the phase changeΦ suffered by microwaves when transmitted through an artificial dielectric composed of metallic discs arranged in a three-dimensional array have been derived with different approaches as follows (i) molecular theory, (ii) electromagnetic theory and (iii) transmission line theory. The phase change depends on the distancet that the wave traverses inside the dielectric and also the spacingd between centre to centre of any two adjacent discs in the three principal directions. Molecular theory indicatesΦ as an increasing function oft, whereas, the other two theories indicateΦ as an oscillatory function oft. The transmission line theory also exhibitsΦ to be real or imaginary depending ont. Experimental values ofΦ as a function oft have been obtained with the help of a microwave (3·2 cms wavelength) interferometer for two dielectrics havingd as 1·91 cms and 2·22 cms respectively.