Agilent 1952-03 free download

File name 1952-03.pdf

HEWLETT-PACKARD JOURNAL T E C H N I C A L I N F O R M A T I O N F R O M T H E - h p - L A B O R A T O R I E S VOL. 3 No. 7-8 UBLISHED 1952 THE HEWLETT-PACKARD COMPANY, 395 PAGE MILL ROAD, PALO ALTO, CALIFORNIA MARCH-APRIL, 1952 A Precision Directional Coupler Using Multi-Hole Coupling DIRECTIONAL couplers have been used auxiliary guide is termed the "directivity" widely in wave guide applications for of the coupler. such purposes as monitoring power, meas The property of dividing power leads to uring reflections, mixing, and for isolation the use of directional couplers in monitoring of signal sources. All of these applications power levels that are greater than the range make use of the property that power flowing of convenient power-measuring equipment. in one direction in the main branch of the For many applications and for measurement coupler induces a power flow in only one work especially, it is desirable that the power direction in the auxiliary circuit. division or "coupling" be constant with fre A common type of directional coupler con quency in order to reduce measurement sists of two sections of waveguide bonded error. together physically and electrically coupled Directional couplers can be divided into by one or more apertures common to both two classes, depending upon whether they guides. Power entering the input arm of the are to be used for monitoring power or for coupler flows down the primary guide and measuring the amplitude of small reflections. divides at the coupling mechanism. The lar Power monitoring usually requires a cou ger portion continues down the prima