Question

If the frequency of operation of a rectangular waveguide above cutoff frequency is increased, then the wave impedance for TE and TM modes are respectively.

Answer 1

${\eta }_{TE}=\frac{{\eta }_0}{\sqrt{1-{\left(\frac{f_c}{f}\right)}^2}}$

${\eta }_{TM}={\eta }_0\sqrt{1-{\left(\frac{f_c}{f}\right)}^2}$

$\therefore Asf\uparrow {\eta }_{TE}\downarrow and{\eta }_{TM}\uparrow$