# Rectangular Waveguides

In the previous section, we have seen that by placing two parallel conducting planes, the electric field was normal to the planes and the magnetic field was tangential to the planes, satisfying the boundary conditions. By placing two more conducting planes, a rectangular tube is formed, known as a rectangular waveguide.

In such a waveguide, the electric field varies with distance having a maximum at the centre. Magnetic field lines curve round and pass through the guide, tangential to the walls. These waveguides provide an alternative to transmission lines particularly at Ultra High Frequencie (UHF) for transmission of electrical energy.

# Properties of TE and TM Waves in Rectangular Waveguide

We find the following quantities for TE and TM mode waves in rectangular waveguides:
1. Propagation constant (Î³)
2. Cut-off frequency (fc)
3. Cut-off wavelength (Î»c)
4. Phase constant (Î²)
5. Phase velocity (vp)
6. Guide wavelength (Î»g)
7. Intrinsic wave impedance (Î·)