Correct Answer : Option (A) : guide diameter
Explanation :
Some applications require dual polarization capability. Circular waveguide has this capability.
These analysis uses cylindrical coordinates.
In circular waveguide TE11 mode has the lowest cut off frequency and is the dominant mode.
If D is diameter of waveguide
λc = 1.706 D for TE11 mode
λc = 1.029 D for TE21 mode
λc = 0.82 D for TE01 mode
λc = 1.306 D for TM01 mode.
