Accession Number:

AD0255743

Title:

INVESTIGATIONS OF MAGNETICALLY TUNABLE NARROW BANDPASS NONRECIPROCAL FILTERS USING FERRIMAGNETIC RESONATORS

Descriptive Note:

Corporate Author:

STANFORD UNIV CALIF STANFORD ELECTRONICS LABS

Personal Author(s):

Report Date:

1961-04-24

Pagination or Media Count:

1.0

Abstract:

The possibility of a narrow-bandwidth, smallinsertion-loss microwave filter with nonreciprocal characteristics is studied, and the findings are reported. The discussion is limited to single-resonance transmission-type filters. In order to obtain tunability over a wide band of frequencies, samples of ferrimagnetic materials such as crystals of yttrium iron garnet, are used as high-Q microwave resonators. An analysis is presented of an equivalent circuit for coupling between 2 microwave circuits using a YIG sphere as the coupling element when the RF magnetic fields due to the 2 circuits are circularly or, in general, elliptically polarized. The experimental device consisted of a cross guide coupler, like a Bethe hole coupler, with only one off-axis aperture which contained the YIG sphere. The experimental results on various filters with different off-axis locations of the aperture are reported. The filters are tunable over the entire X-band by changing the dc magnetic field. The experimental results obtained are in good agreement with those predicted from the theory. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE