Advances in Non-reciprocal devices and materials

The circulator is historically an integral component of Defense and commercial phased array radar and communication systems. Unlike the vast majority of other components in the transmit and receive module (TRM), which have enjoyed the benefits of continued miniaturization and cost reduction, ferrite circulators have remained largely unchanged since their introduction. In this talk, we will present the foundations of materials optimized for use in circulators and isolators. Emphasis will be placed upon the hexaferrite systems (i.e., magnetoplumbite structure) since they uniquely provide internal magnetic fields capable of both self-bias properties and high frequency (i.e., from Ka through W bands) performance. Self-bias properties allow for the long-sought redesign of the circulator as a two-dimensional construct that is potentially integratable with active components of the TRM as microwave integrated circuits. We will also present the challenges and opportunities associated with self-biased circulator integration, design, process flow, product performance, etc. With handheld mobile communication (i.e., 5G) technology proposed to operate at mm-wavelength the development of two-dimensional full duplexing self-biased circulators having substantial weight and volumetric efficiencies would be required in heavily integrated, low cost mm-wave phased array communication systems and platforms.