
256 Microwave Engineering
7.7 Waveguide Terminations
Electromagnetic wave is often passed through a waveguide in order to trans-
fer the energy from a source into space. The impedance of a waveguide does
not match the impedance of space. An abrupt change in impedance results
in standing waves. If there is no proper impedance matching, the presence
of standing waves may decrease the efciency of the system. To avoid the
formation of standing waves the change in the impedance at the end of a
waveguide has to be gradual. Such gradual change can be obtained by ter-
minating the waveguide with a funnel-shaped horn. The type of horn to be
used depends ...