Advances in Ferrite Redundancy Switching for Ka-Band Receiver Applications

Abstract

Previously limited to simple redundancy switching schemes, such as 2-for-1, a ferrite-based equivalent of the traditional 10-for-8 mechanical redundancy switch (R-switch) was developed. Standby redundancy of active components, such as low-noise amplifiers (LNAs), is essential for space missions, and the demand for Ka-band communications satellites is rapidly increasing. Advances in the reduction in size, mass, and insertion loss of higher complexity ferrite circulator switch networks have made ferrite switches a feasible alternative to mechanical switches for redundancy switching applications. This work set out to understand how these advances could be applied to a higher level of redundancy switching, such as 10-for-8, in order to meet the growing needs of the Ka-band satellite market. A prototype redundant LNA assembly was designed and manufactured. The results herein show that the reduced-size ferrite switch networks provide considerable bandwidth and insertion loss improvements over traditional ferrite switch networks. The 10-for-8 redundant LNA assembly, based on ferrite switching and developed by Honeywell (formerly EMS Technologies) provided excellent noise-figure performance of 2.1 dB at 25 °C in Ka-band. More significantly, the high level of integration in the ferrite switch rings and in the interface between the ferrite switches and LNAs results in size and mass savings of 50% over the mechanical R-switch approach, constructed of individual components.