Browse Prior Art Database

Broad Band Active Directional Coupler

IP.com Disclosure Number: IPCOM000090762D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Jutzi, W: AUTHOR

Abstract

In a passive directional,coupler lines 1, 3 and 2, 4 are coupled over a length S. A signal applied at port 1, drawing A, appears at port 2 as well as port 3, but not at port 4. The frequency range of transmission at port 2 is quite limited and is smaller than 0

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Broad Band Active Directional Coupler

In a passive directional,coupler lines 1, 3 and 2, 4 are coupled over a length
S. A signal applied at port 1, drawing A, appears at port 2 as well as port 3, but not at port 4. The frequency range of transmission at port 2 is quite limited and is smaller than 0<S/lambda<0.5. S is the coupling length and lambda is the wavelength of the signal on the coupler. This frequency range can be extended by a nonuniform distribution of coupling parameters over the length S. Such high-pass passive directional couplers have lower directivity, i.e., ratio of signal at port 4 to signal at port 2. Neither of these directional couplers is suited for transmission of pulses having a low-pass spectrum.

The directional coupler in drawing B, having active as well as passive sections, can cover a very broad frequency spectrum without undue losses. Passive line sections are interconnected alternately with transistors, e.g., field effect transistors. These are mounted on a common conductive substrate. The passive line sections are printed on an insulating layer covering the substrate. The transistors can be of the extended type, thus constituting a substantial part of the lines. The transconductance of the transistors is now a more important parameter of the directional coupler than are inductances and capacities.

A signal arriving at port 1 appears at ports 3 and 4. Both have a low-pass transmission characteristic, but do not within a certain freque...