Agilent 1953-01 free download

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HEWLETT-PACKARD JOURNAL TECHNICAL INFORMATION FROM THE -h p- LABORATORIES VOL. 4 No. 5-6 PUBLISHED BY THE HEWLETT-PACKARD COMPANY, 395 PAGE MILL ROAD, PALO ALTO, CALIFORNIA JAN. -FEB., 1953 More About the -hp- Precision Directional Couplers AV earlier issue1 described the design of incident on any device connected at the end the -hp- 10 and 20 db precision multi- of the guide. The other part of the power is hole directional couplers. These couplers are coupled into the auxiliary guide. It is a prop distinguished by a relatively constant coup erty of directional couplers that the power ling over a wave guide range of frequencies coupled into the auxiliary guide flows essen and by an unusually high directivity of more tially in only one direction. In the -hp- coup than 40 db, even for coupling values as tight ler, this power flow is in the same direction aslOdb. as the power in the primary guide. The multi-hole coupler design has now In the ideal condition all of the power been extended to a 3 db coupler, that is, a coupled to the auxiliary guide should flow in coupler in which half the power entering the the same direction. Practically, however, a main guide is coupled into the auxiliary portion of the auxiliary guide power flows guide. This coupler has the same constancy in the reverse direction. The ratio of auxil of coupling and high directivity as the 10 and iary guide power flowing in the desired di 20 db values. In addition, specifications have rection to that flowing in the reversed direc been established for all couplers on the basis tion is termed the directivity of the coupler. of production experience. In the past the use of directional couplers has The -hp- multi-hole couplers consist of been limited by lack of high directivity over two sections of wave guide mutually coupled a full wave guide frequency range. It is this by two rows of coupling holes (Fig. 2). feature of high directivity over a broad range Power entering the input arm of the coupler