Ferrite/Dielectric High Power Phase Shifter Development. Part III. Electromagnetic Wave Propagation in Multi-Layer Composite Media.

Abstract : The significance of this work to the Air Force is the development of theory which shows that combining ferrites and dielectrics in stratified and/or coplanar configurations offers a route to novel band switching circulators, filters, and other various exotic devices. The use of arc-plasma spray fabrication makes economical fabrication feasiable. The propagation of electromagnetic energy in radial waveguides involving layers of ferrites and /or dielectics is examined. The operation of microstrip circulators using such media was predicted and a composite circulator built and tested. The device exhibited a 1 dB insertion loss over a 15 dB isolation bandwidth of 3.3 GHz in X-band. The two theoretical circulation conditions of Bosma were reformulated to account for the effects of the composite medium. Other geometries studied included the shorted junction circulator, the ring circulator, and the radially inhomogeneous circulator. It was found that increased bandwidth should be obtained with the shorted junction circulator while significant size reduction (about one half) is possible with a ring configuration. (Author)