Assessment of magnetic materials for use in quasi-optical non-reciprocal devices operating at frequencies above 90 GHz

• Published in: 2007 Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics pp. 873 - 874
• Main Authors: Donnan, R.S., Martin, D.H., Wylde, R.J., Bin Yang
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-09-2007
• Subjects: Attenuation; Bandwidth; Chemical processes; Composite materials; Current measurement; Frequency measurement; Magnetic devices; Magnetic materials; Magnetic properties; Polarization
• ISBN: 1424414385; 9781424414383
• ISSN: 2162-2027
• DOI: 10.1109/ICIMW.2007.4516771

High-performance quasi-optical non-reciprocal devices are required for use in many current and future measurement systems operating at millimetre-wave/submillimetre-wave frequencies. In such a device, free-space quasi-collimated linearly-polarised signal-beams pass normally through a plane plate of a magnetic material that is uniformly magnetised perpendicularly to its surfaces and is of a thickness that will give a 45-degree Faraday rotation of a linearly polarised signal beam in a single pass. To find materials having acceptable magneto-static and rf properties for use in mm-wave/submm non-reciprocal devices has therefore involved in screening samples of permanent-magnet materials from many suppliers. There is now scope for the development of improved materials for operation over wider millimetre-wave bandwidths, or at higher submm-wave frequencies, because the chemical compositions, and the forming processes, of the presently available hexaferrites were not selected with a view to minimising mm-wave/submm-wave attenuation.