MINIATURE THIN-FILM INDUCTORS
Abstract
Research was continued on the fabrication of miniature thin film inductors using flat spiral conducting paths in combination with highpermeability ferrite material. Two approaches to the problem were investigated. The first used copper spiral conducting paths and bulk ferrite wafers with an intrinsic initial permeability of 190 and a Q-value of 200 as measured at a frequency of 1 mc per second. The second method proposed the use of noble metal conductors which were surrounded by a medium of thick ferrite film. The ferrite film was deposited by a pyrohydrolytic spray technique which was compatible with the use of the noble metals as the spiral conducting path. The goal of the program was to obtain inductors with values from 38 microhenries to 1 millihenry with a minimum Qvalue of 100 as measured at a frequency of 1 mc. The largest inductance value obtained using the bulk ferrite was 153 microhenries with a Q-value of 20. The inductance values that were obtained were found to be limited by an air gap in the magnetic path produced in the bulk ferrite assembly. Described are various methods studied for obtaining ferrite thick films with usable magnetic properties. The method that proved to be most useful was the pyrohydrolytic spray of a chloride solution of the desired metal cations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1962
- Accession Number
- AD0294768
Entities
People
- F.r. Gleason
Organizations
- Motorola Mobility