Low loss self-biased ferrite circulators for size and weight sensitive applications requiring high power handling and temperature stability

Self-biased ferrite circulator and isolator devices have previously been demonstrated and discussed in the literature. While operation without biasing magnets was verified, all the prototypes constructed thus far exhibited relatively high loss and poor isolation, which made them unsuitable for practical applications. Furthermore, due to the strong internal magnetic field in the ferrite materials utilized to develop self-biased circulators in the past, the frequency of operation was restricted to above 20 GHz. Metamagnetics developed and patented novel materials fabrication and orientation techniques that lead to exceptionally low magnetic losses. Further, the aforementioned orientation techniques have been successfully applied to substituted hexagonal ferrite materials that possess low uniaxial anisotropy, thus allowing self-biased devices in the 8 to 20 GHz frequency band. Building upon these enabling advances, in this Navy SBIR Phase II effort, the development of low loss self-biased circulators for X-band applications is pursued. In addition, enhanced temperature stability and power handling capability over existing state-of-the-art are undertaken in this program to help prevent ferrite circulator devices from becoming the bottleneck in the development of next generation T/R modules and AESA systems relying upon wide bandgap semiconductor active devices.