Microwave and Wireless Communications Technology

106 WAVEGUIDES

KEY EQUATIONS

1. Group velocity in a waveguide:

Vg = csina

2. Phase velocity in a waveguide:

C

sina

3. Relationship between phase and group velocity:

-

4v~v~

4. Relationship between frequency and free-space wavelength:

c = FXo

5. Phase velocity as a function of wavelength:

z~

v~- Z

6. Wavelength in a waveguide:

Z= V.;to

c

7. General mode equation for air dielectric:

8. Cutoff wavelength:

~,=2a

9. Cutoff frequency:

C

Fc-=~

2a

10. General mode equation for all dielectrics:

1 l/ )2

Key Equations 107

11. Cutoff