IEEE 147-1979 pdf free.IEEE Standard Definitions of Terms for Waveguide Components.
IEEE 147 A structure used to interconnect two waveguides which differ in size ortype.If the modes of propagation also differ,the adapter functions as a mode transducer.attenuator， waveguide. A waveguide component that reduces the output power relative tothe input by any means, including absorptionand reflection.barretter. A form of bolometer element havinga positive temperature coefficient of resistivitywhich typically employs a powerabsorbingwire or thin metal film.
bend，waveguide. A section of waveguide ortransmission line in which the direction of thelongitudinal axis is changed. In common usagethe waveguide corner formed by an abruptchange indirection is considered to be abend.
bolometer (bolometer unit，bolometric instrument). A term commonly used to denote thecombination of a bolometer element and abolometer mount; sometimes used impreciselyto refer to a bolometer element.
bolometer element (bolometric detector). Apower-absorbingelement which usestheresistance change related to the temperaturecoefficient of resistivity (either positive ornegative) as a means of measuring or detectingthe power absorbed by the element. (Seebarretter, thermistor.)
bolometer mount. A waveguide or transmission-line termination that can house a bolometer element.
calorimeter，waveguide. A waveguide or transmission-line structure which uses the temperature rise in a medium as a measure of absorbedpower.The medium,typicallywater or a thermoelectric element,is either the power-absorbing agent or has heat transferred to itfrom a power-absorbing element.
cavity resonator. A resonator formed by avolume of propagating medium bounded byreflecting surfaces.(See also resonator，wave-guide.)
choke joint (choke coupling). A connectiondesigned for essentially complete transfer ofpower between twowaveguides withoutmetallic contact between the inner walls of thewaveguides.It typically consists of one coverflange and one choke flange.
contact joint (contact coupling). A connectiondesigned for essentially complete transfer ofpower between two waveguides by means ofmetallic contact between the inner walls ofthe waveguides. It typically consists of twocontact flanges.
corner, waveguide. See bend, waveguide.
coupling aperture (coupling hole，couplingslot). An aperture in the bounding surface ofa cavity resonator, waveguide.transmissionline,or waveguide component,which permitsthe flow of energy to or from an externalcircuit.
coupling loop. A conducting loop which permits the flow of energy between a cavityresonator，waveguide，transmission line,orwaveguide component and an external circuit.coupling probe. A probe which permits theflow of energy between a cavity resonator,waveguide，transmission line，or waveguidecomponent and an external circuit.IEEE 147 pdf download.