Question

The dominant mode for rectangular waveguide is:

• A. \( TE_{11} \)
• B. \( TM_{11} \)
• C. \( TE_{01} \)
• D. \( TE_{10} \)

Hint:

In a rectangular waveguide, the dominant mode is \( TE_{10} \).

Answer 1

The Correct Option is D

The dominant mode for a rectangular waveguide is the mode with the lowest cutoff frequency. For a rectangular waveguide, the cutoff frequency for TE modes is given by:
\[ f_c = \frac{c}{2} \sqrt{\left( \frac{m}{a} \right)^2 + \left( \frac{n}{b} \right)^2} \] where \( a \) and \( b \) are the dimensions of the waveguide, and \( m, n \) are the mode indices. The lowest mode is \( TE_{10} \), as it has the lowest cutoff frequency.