What does the physical size of a waveguide affect?

The physical size of a waveguide is directly related to its ability to handle different frequencies. Specifically, the minimum frequency that a waveguide can effectively transmit is primarily determined by its dimensions, especially the width and height of the waveguide.

When a waveguide is designed, its dimensions are optimized not only for specific frequencies but also to ensure that it can adequately support the propagation of electromagnetic waves. At lower frequencies, the wavelength of the signal is longer, and if the waveguide dimensions are too small, the signal will not propagate through it effectively. This is tied to the concept of the cutoff frequency, which is the lowest frequency wavelength that can propagate through the waveguide without significant attenuation.

Thus, if the physical size of the waveguide is inadequate for the wavelength of the transmitted signal, it will behave ineffectively or be grossly inefficient in propagating those signals, limiting communication and transmission capabilities. Understanding this principle is essential for selecting the appropriate waveguide for specific applications, ensuring efficient signal transmission without unwanted losses.