HIGH-Q AND WIDELY TUNABLE ALL-SILICON RESONATORS AND FILTERS FOR MICROWAVE AND MILLIMETER-WAVE APPLICATIONS

The concept of a single portable communication device that can support a variety of wireless standards has been implemented for several years now. Presently, this is achieved by integrating multiple radios into a single device. The rapidly increasing demand of incorporating new standards with the existing RF front-end architecture has greatly increased the design complexity, cost, size, weight and power losses. Next generation software defined radios(SDR) are expected to efficiently utilize the available spectrum using a compact, low cost but highly reconfigurable hardware with minimal power consumption. The development of a truly reconfigurable SDR is currently being challenged by its RF front-end design due to non-availability of a suitable tunable filter technology that can fulfill the stringent SDR requirements. A high-performance, continuously tunable broadband filter that is small and consumes little power has the essential characteristics needed to support truly reconfigurable radios development.

This work presents a novel fabrication technology for realizing compact, High-Q and widely tunable cavity filters. This all-silicon technology has been successfully employed to demonstrate tunable resonators/filters in C, X, Ku and K bands with simultaneous high quality factors (> 500) and tuning ratios (>  2:1). It is shown that by employing precise micro-fabrication techniques, the measured RF and tuning performance of the fabricated device closely matches the simulated results (> 75%). The capability for monolithic (system-on-chip) integration, low cost batch processing and compatibility with CMOS processing are some of the key advantages of all-silicon technology. This technology has a great potential for developing high performance tunable resonators and filters necessary for reconfigurable RF front-ends in microwave and millimeter-wave SDR applications.