Gyrator: Function and Basics Explained

Anisotropic materials exhibit varying properties depending on the direction. Ferromagnetic compounds like YIG and ferrites are common examples of materials with anisotropic properties. A ferrite is essentially a non-metallic substance.

When a circularly polarized wave travels through a ferrite rod subjected to an axial magnetic field, the polarization axis will rotate clockwise. The extent of this rotation depends on both the strength of the magnetic field and the dimensions of the ferrite rod.

This principle is the foundation of the gyrator’s design.

The gyrator is a ferrite-based device utilized in RF and microwave circuit designs to achieve a phase shift of approximately 180 degrees. It is fundamentally a two-port device. The scattering matrix (S-matrix) of an ideal lossless gyrator, along with its circuit symbol, is depicted in the figure above. In essence, the gyrator acts as a phase shifter providing a 180-degree phase shift.