Microwave heating cavities and applicators - Microwave-Assisted Concrete Technology: Production, Demolition and Recycling - page 197

Filament Leads

Assembly
Base Plate

Magnetron
Dome

(a)

Output Coupling Loop

Resonating Cavity

Copper Anode
Block

Oxide Coated
Cathode

Leads to Cathode
& Heater

(b)

Figure 6.1 (a) A commercially available magnetron; (b) the internal structure of a
magnetron.

To warm the magnetron's filament before commencing microwave gen-
eration, a filament transformer is used to preheat the magnetron. Figure 6.3
shows a typical filament transformer that can be used to heat the filament
of a 2.45-GHz magnetron by passing a 30-amps current through it for
almost 4 minutes.

6.2.2 Power transmission unit
The microwave power generated is delivered to the load (e.g., concrete or
RCA) through a set of waveguide components. As shown in Figure 6.4,
typical high-power configurations of the waveguide components usually