Thin Ferrite Phase-Shifters for Integrated Microwave Devices

Abstract
Theoretical and experimental investigations have been conducted to determine the feasibility of microwave devices which utilize the remanent magnetization characteristics of dimensionally thin magnetic materials. A technique for producing phase‐shift (both reciprocal and nonreciprocal) was theoretically developed and proven experimentally. By investigating the thin sample geometry (ferrite slabs 5 to 20 mils thick), we had the opportunity to use commercially available materials to prove the theory and at the same time extend it to a device configuration which is topologically close to the thin film. Phase‐shifting elements composed of a meander line circuit deposited on a thin ferrite slab have been built and tested. By a modification of the meander‐line‐circuit dimensions and the direction of the ferrite magnetization relative to the circuit, both reciprocal and nonreciprocal devices can be made. A microstrip arrangement of the device was adopted so that the theory could be proved in a structure which closely approximates the ultimate thin‐film application.