Integrated Radio Frequency Isolator

Abstract

Radio frequency isolators based on ferrite junction circulators have been the dominant isolator technology for the past fifty years, yet they have not been integrated practically because ferrites are generally incompatible with semiconductor processes and their size is inversely proportional to their operating frequency. Hall isolators are another approach whose operating frequency is independent of their size, are compatible with semiconductor processes and are thus appropriate for integration. Through simulation, this thesis demonstrates that these devices can be on the order of microns in size and have a bandwidth from DC to over a terahertz. Measurements of an unoptimized Hall element demonstrate an operating bandwidth from DC to 1127 MHz. A technique using multi-contact Hall plates is shown to reduce isolator insertion loss to 0.89 dB, which is competitive with ferrite-based devices.