Low-Loss Gyromagnetic Coupling through Single Crystal Garnets

Abstract

This paper describes methods of synthesizing filters and gyrators using strong coupling of a small volume of ferrimagnetic material to an electromagnetic circuit. The small volume of material is treated as a lumped element resonator and it is shown that energy can be coupled through this resonator with low loss. The device uses the material for low-loss transmission of microwave energy. The practical realization of devices using this principle depends upon strong coupling of the material to the circuit and the use of “low-loss” materials such as single crystal garnets. The synthesis leads to the design of physically small electronically tunable filters, compact circulators and isolators. Such techniques may also be useful for the realization of low-frequency lumped element devices. Calculations and preliminary tests indicate that devices of this type will lead to the practical realization of solid state TR cells.