SBIR Phase I: Ultra-Broadband Ferrite Circulators/Isolators

This Small Business Innovation Research (SBIR) Phase I Project addresses the development of Innovative Ultra-Broadband Ferrite Circulators/Isolators providing a transmission bandwidth broader than a 10:1 frequency ratio. A traditional circulator junction utilizing a single ferrite material results in a 3:1 bandwidth. A non-traditional stripline junction circulator for which the transmission band extends from 1.6 to 16 GHz has been designed and fabricated. This circulator design involves 3 different kinds of ferrite materials to be packed as tiles to form a composite junction. Even broader bandwidth has also been theoretically predicted, if more ferrite materials are used to compose the junction, rendering a bandwidth covering from 1 to 20 GHz. Researches on broadband transformer circuits are thus proposed, allowing for 50 S impedance to be realized with the input/output ports accompanying the operation of the broadband circulator/isolator junctions. The proposed innovative circulators/isolators can be used as universal instruments under broadband considerations. For example, it can be used in measurements requiring interband operation, such as encountered in a Network Analyzer performing scattering parameter measurements. In radiometry applications it allows for narrow-width electromagnetic pulses to be used with monostatic radars. Multiple radars operating at distinctive frequency bands can be combined to share a common antenna aperture so as to reduce overall radar cross section.