Accession Number : ADA257512


Title :   Theoretical Analysis of Microwave and Millimeter Wave Integrated Circuits Based on Magnetic Films


Descriptive Note : Annual rept. 1 Oct 1991-30 Sep 1992


Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR ELECTROMAGNETIC AND ELECTRONIC SYSTEMS


Personal Author(s) : Kong, J A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a257512.pdf


Report Date : 13 Nov 1992


Pagination or Media Count : 68


Abstract : A macroscopic model is proposed to explain nonlinear electromagnetic phenomena in superconductors. Nonlinear constitutive relations for electromagnetic problems are derived by modifying the linear London's equations. The superelectron number density ns is a function of the applied current density. The critical current density Jc is derived classically from a critical energy Ec. For temperature T not equal to 0, the concept of critical current Jc does not imply an abrupt transition of the whole sample from a superconducting state to a normal state when J Jc. A rather smooth variation of ns(J) is shown instead. The relation, ns(J), is derived from the Maxwellian distribution of electron velocities at a certain temperature T and a certain macroscopic current density J. Agreement has also been found between this ns(J,T) model and the temperature dependance of ns in the two-fluid model. The nonlinear conductivities sigma s(J) and sigma n(J) are obtained from the London's equation and the ns(J) function. Nonlinear resistance R(I), kinetic inductance Lk(I) and surface impedance Zs(I) in thin wire, slab, and strip geometries of superconductors are calculated. A general scheme of solving nonlinear electromagnetic problems in superconductors is proposed. A good agreement between the theory and experiments has been found.


Descriptors :   *FILMS , *INTEGRATED CIRCUITS , *FERROMAGNETIC MATERIALS , SUPERCONDUCTORS , NONLINEAR SYSTEMS , RICCATI EQUATION , ELECTRICAL RESISTANCE , DIFFERENTIAL EQUATIONS , ELECTRONS , CURRENT DENSITY


Subject Categories : Electrical and Electronic Equipment
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE