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Superconducting Delay Line With Electronically Variable Delay

IP.com Disclosure Number: IPCOM000077969D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Harris, EP: AUTHOR

Abstract

A superconducting delay line with electronically variable delay is described. The device consists of a superconducting strip line having a conductor to which variable DC voltage is applied. This voltage causes a charge to be deposited on the conductor. The charge changes the penetration depth of the superconductor, thus affecting the inductance of the strip line; thereby changing the propagation velocity of traveling waves on the strip line.

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Superconducting Delay Line With Electronically Variable Delay

A superconducting delay line with electronically variable delay is described. The device consists of a superconducting strip line having a conductor to which variable DC voltage is applied. This voltage causes a charge to be deposited on the conductor. The charge changes the penetration depth of the superconductor, thus affecting the inductance of the strip line; thereby changing the propagation velocity of traveling waves on the strip line. This effect can be quite pronounced in favorable structures because: (a) the inductance of a superconducting "slow- wave" strip line is a strong function of the penetration depth, due to the large kinetic inductance of the superconducting electrons, and (b) the penetration depth cam be made a strong function of electronic charge density in certain superconducting materials, such as superconducting semiconductors.

A transmission line structure 1 is shown schematically in cross section. The upper conductor 2 which is spaced from a superconducting ground plane 3 by a dielectric layer 4 is chosen to be a superconductor whose properties vary with electron concentration, n; for example, SrTiO(3)./1/ The dimension t is made very small; much smaller than the penetration depth lambda of SrTiO(3), and also small enough so that an appreciable charge concentration can be applied to conductor 2 from a source 5 via switch 6 without breaking down the dielectric. For example, if t...