
168 Microwave Engineering
In view of this unique effect, many useful devices are made to operate
at microwave frequencies. These include gyrators, isolators, circulators,
phase changers, attenuators, modulators and microwave switches. Some of
these devices are described in the following sections.
5.4 Non-Reciprocal Ferrite Devices
Figure 5.6 shows the devices that allow propagation of the wave only in one
direction. These, referred to as non-reciprocal devices, mainly include gyra-
tors, circulators and isolators. The working of these devices is solely based
on the principle of Faraday’s rotation. All non-reciprocal devices ...