TE10 mode is the dominant mode with a>b, since it has the lowest attenuation of all modes. Either m or n can be zero, but not both.
Rectangular Waveguide - TE10; (TM11 in case of TM waves) Circular Waveguide - TE11;
The ratio of the area of a circular waveguide to that of a rectangular waveguide with the same dominant mode cutoff frequency can be derived from the relationship between their dimensions and the cutoff frequency. For the dominant mode (TE11 for circular and TE10 for rectangular), the cutoff frequency depends on the waveguide's geometry. Generally, the area of the circular waveguide is greater than that of the rectangular waveguide when both are designed to support the same cutoff frequency. Specifically, the area ratio can be expressed as ( A_{\text{circle}} / A_{\text{rectangle}} = \frac{\pi a^2}{ab} ) where ( a ) is the radius of the circular waveguide and ( b ) is the width of the rectangular waveguide, leading to a ratio dependent on their respective dimensions.
Rectangular Waveguide - TE10; (TM11 in case of TM waves) Circular Waveguide - TE11;
The ratio of the area of a circular waveguide to that of a rectangular waveguide with the same dominant mode cutoff frequency can be derived from the relationship between their dimensions and the cutoff frequency. For the dominant mode (TE11 for circular and TE10 for rectangular), the cutoff frequency depends on the waveguide's geometry. Generally, the area of the circular waveguide is greater than that of the rectangular waveguide when both are designed to support the same cutoff frequency. Specifically, the area ratio can be expressed as ( A_{\text{circle}} / A_{\text{rectangle}} = \frac{\pi a^2}{ab} ) where ( a ) is the radius of the circular waveguide and ( b ) is the width of the rectangular waveguide, leading to a ratio dependent on their respective dimensions.
TE10