MICROWAVE PROPAGATION IN PERIODIC FERRITE STRUCTURES.
Abstract
A new structure for the propagation of microwave signals has been investigated. It consists of a periodic, linear array of single crystal YIG spheres operating in the uniform mode of precession and coupled together by their external magnetic fields. The concept of a YIG sphere as a microwave resonator is thereby extended to a transmission system consisting of coupled resonators. The array is found to have the properties of a band pass filter whose center frequency and bandwidth are controllable by a dc magnetic field in which the array is immersed. The signal frequency can thus be tracked and characteristics of propagation such as phase constant, attenuation, and group and phase velocities can be controlled electronically at any given frequency. This suggests a number of possible applications such as an electronically variable microwave delay line, an electronically controllable band pass filter, and a wave supporting structure for traveling wave amplifiers and oscillators. Theoretical expressions are developed which describe the propagation and these are verified experimentally. Equations are given for phase constant and attenuation. Computer programs are employed to give exact curves of phase constant, attenuation, group velocity and time delay, and a number of examples are considered. Two interesting effects apparent from the theory and illustrated by the examples are the variation of the pass band width as a function of the orientation of the dc magnetic field and the existance of higher order, usually highly attenuated, modes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1967
- Accession Number
- AD0819850
Entities
People
- W. F. Egan
Organizations
- Stanford University