Superconducting filters for wireless communications: a reappraisal

Since 1992, several U.S. companies have developed high temperature superconducting (HTS) filters with low insertion loss and high Q-factors for wireless applications. With the promise of HTS filters to provide increased basestation sensitivity (leading to increased range for rural basestations), better interference rejection, and improved quality of cellular and PCS services, predictions of a large market were made, Booz Allen first studied this emerging market in 1995, when the technology was still relatively new. Today, representatives of many of the leading U.S. wireless service providers and equipment manufacturers are familiar with the capabilities of HTS filters, now frequently combined with cryogenic LNAs. In addition, incumbent technologies have improved, and possible alternative solutions developed. Using Booz Allen´s proven market characterization approach, this paper re-examines the requirements of the cellular/PCS market and includes order-of-magnitude estimates of market sizes for the rural range extension case. Drivers of adoption, competing technologies, emerging market trends, new innovations, and the impact of cryocooling are all considered. We conclude that the domestic U.S. market may be slower to develop than earlier estimates predicted, and consider strategies for HTS filter vendors to grow the market.