DOMINANT MODEThe easiest mode to produce in a waveguide, and also, the most efficient
mode in terms of energy transfer.
DRIFT SPACEIn an electron tube, a region free of external fields in which relative electron
position depends on velocity.
DUMMY LOADA device used at the end of a transmission line or waveguide to convert
transmitted energy into heat so no energy is radiated outward or reflected back.
E-FIELDElectric field that exists when a difference in electrical potential causes a stress in the
dielectric between two points.
E-TYPE T-JUNCTIONA waveguide junction in which the junction arm extends from the
main waveguide in the same direction as the E-field in the waveguide.
ELECTRIC FIELDSee E-field.
ELECTRONIC TUNINGIn a reflex klystron, changing the frequency and output power of
the tube by altering the repeller voltage.
ELECTROLYSISChemical changes produced by passing an electrical current from one
substance (electrode) to another (electrolyte).
ELECTRON ORBITAL MOVEMENTThe movement of an electron around the nucleus of
ELECTRON SPINThe movement of an electron around its axis.
ELEVATION ANGLEThe angle between the line of sight to an object and the horizontal
FARADAY ROTATIONThe rotation of the plane of polarization of electromagnetic energy
when it passes through a substance influenced by a magnetic field that has a component in
the direction of propagation.
FERRITEA powdered and compressed ferric oxide material that has both magnetic properties
and resistance to current flow.
FERRITE SWITCHA ferrite device that blocks the flow of energy through a waveguide by
rotating the electric field 90 degrees. The rotated energy is then reflected or absorbed.
GRID-GAP TUNINGA method of changing the center frequency of a resonant cavity by
physically changing the distance between the cavity grids.
GROUP VELOCITYThe forward progress velocity of a wave front in a waveguide.
H-FIELDAny space or region in which a magnetic force is exerted. The magnetic field may be
produced by a current-carrying coil or conductor, by a permanent magnet, or by the earth
H-TYPE T-JUNCTIONA waveguide junction in which the junction arm is parallel to the
magnetic lines of force in the main waveguide.