Raytheon Company

Albert E Paladino

Edward A Maguire, Jr

Paul F Weihrauch

Dennis W Readey

A group of dielectric compounds and mixtures of dielectric compounds with useful properties at microwave frequencies is disclosed. The dielectric materials are temperature compensated, have relatively high dielectric constants, and comprise the group of BaTi.sub.4 O.sub.9, and mixtures of Li.sub.2 TiO.sub.3 and Li.sub.4 Ti.sub.5 O.sub.12, MgTi.sub.2 O.sub.5 and TiO.sub.2, Zn.sub.2 TiO.sub.4 and TiO.sub.2, and BaTi.sub.4 O.sub.9 and TiO.sub.2.

Microwave dielectrics

A method of making an integral toroidal magnet comprising the steps of compacting suitable magnetic powder material into a toroidal shape while subjecting it to a particle aligning magnetic field, hot pressing the compacted powder toroid in a confining die at a temperature and pressure sufficient to cause shrinkage of the toroid in the axial direction and provide a packing density greater than 93% of the theoretical maximum value and substantially unidimensional shrinkage, heat treating the toroid at a temperature sufficiently higher than the hot pressing temperature to achieve an enhanced crystallographic alignment equivalent to the alignment obtained by sintering, annealing the toroid at a temperature sufficiently lower than the heat treating temperature to provide a magnetic coercivity similar to the coercivity achieved by annealing after sintering, and magnetizing the heat treated toroid in the direction of crystallographic alignment.

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Needham, MA, United States of America

Albert E Paladino