Lesson 7_Microwave Devices MICROWAVE DEVICES • Conventionally, the lower boundary for microwave signals is set at 1 GHz • At low fr equencie s, the inductance an d capac it ance of component leads can be ignored; at microwave frequencies, even sho rt connect ing lea ds have sig ni fic ant capac iti ve and inductive reactance, so component construction becomes critical Passive Components • Using waveguides requires the redesign of some components that used with feedlines • Typical passive components include: Bends and Tees Cavity Resonators Attenuators and Loads Circulators and Isolators a. Bends and Tees • Anything that changes the shape or size of a waveguide has an effect on the electric and magnetic fields inside • As long as bends or twists are gradual, the effect is minimized b. Cavity Resonators • A cavity resonator is designed to be resonant with the signal being transmitted • Waves are in phase with the incident signal • The Q for resonant cavities is very high • Cavities are tuned by changing their size 1