Resonant isolator for maser amplifier

摘要

An isolator is described for use in a low-noise maser amplifier, which provides low loss across a wide bandwidth and which can be constructed at moderate cost. The isolator (40) includes a train of garnet or ferrite elements (50, 52) extending along the length of a microwave channel (14) parallel to the slow-wave structure (24), with the elements being of staggered height, so that the thin elements (50) which are resonant to the microwaves are separated by much thicker elements (52). The thick garnet or ferrite elements reduce the magnetic flux passing through the thin elements (50), to permit altering of the shape of the thin elements so as to facilitate their fabrication and to provide better isolation with reduced loss, by increasing the thickness (T) of the thin elements and decreasing their length (L) and width (W).