STTR Phase II: Tunable RF Front Ends for Wireless Devices

This Small Business Technology Transfer (STTR) Phase II project addresses the creation of tunable radio frequency filters for future wireless devices. The proposed approach combines research on advanced magnetic materials with research on nano-structuring of magnetic and non-magnetic materials with the goal of achieving an order of magnitude or more increase in quality factor (Q) and maximum value of inductors (Ls) used to implement tunable inductor capacitor (C) filters at frequencies up to 5GHz; specifically Ls > 50nH, Qs > 100, and self-resonance frequencies > 3 GHz. The approach is to economically deposit oriented high-moment magnetic materials in a non-magnetic matrix to achieve high permeability while avoiding eddy current losses at high frequencies through the use of nano-structuring. In addition, this research will explore novel circuit design techniques for radio front ends that will exploit inductors fabricated using the proposed structures to implement tunable radio frequency filters suitable for advanced wireless devices. Novel circuit design approaches must be developed because the LC filters built using the proposed technology will have significantly lower Q than existing surface acoustic wave filter technology; but will offer new advantages of tunability, circuit topology flexibility, and amenability to fabrication over integrated circuits. The broader impact/commercial potential of this project is that it would contribute to making ?cognitive radios? practical. Cognitive radios are ones that can opportunistically seek out portions of the frequency spectrum that are currently unused in their local vicinity and then use them for communications, dramatically reducing congestion in the airwaves of major cities by allowing aggressive reuse of frequency spectrum. Cognitive radios have the potential to increase the aggregate data rate available in dense urban environments by more than an order of magnitude. Today, such radios are economically unattractive because the RF front end filters would have to be implemented using one fixed surface acoustic wave filter for every possible band. However, the tunability of the proposed enhanced LC filters greatly facilitates the creation of low cost cognitive radios. In terms of commercial impact, the proposed tunable LC filters would revolutionize how RF front end modules for cellular radios (a >$7B/year market) are designed. Translating this into societal impact, the proposed technology has the potential to increase the data rate with which the population at large can access data stored on the network using wireless devices in the mobile internet by more than an order of magnitude.