Main components of a microwave device

Both multi-mode and focused microwave devices consist of four major components, 

The applicator is the zone in which microwaves are applied to the sample. It can be a multi-mode cavity where microwaves are randomly dispersed or the waveguide itself, in which case the sample vessel is placed directly inside it to focus the microwave radiation onto the sample. 

Most commercial ovens, whether single-mode or multi-mode models, are protected from potential damage caused by reflected energy by an automatic cut-off mechanism also, some ovens provide additional protection in the form of a circulator that directs reflected energy into a dummy load. A circulator is essentially a device that uses ferrites and static magnetic fields to allow microwaves to pass in the forward direction but diverts reflected waves into a dummy load where the energy is harmlessly dissipated as heat. 

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