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Fast Tuning, Analog Notch Filters
Navy SBIR 2008.1 - Topic N08-083 ONR - Mrs. Tracy Frost - [email protected] Opens: December 10, 2007 - Closes: January 9, 2008 N08-083 TITLE: Fast Tuning, Analog Notch Filters TECHNOLOGY AREAS: Sensors, Electronics, Battlespace ACQUISITION PROGRAM: Radio Frequency Antennas & Topside Program Manager, code PMW 180-D4/E2 OBJECTIVE: Develop analog filters capable, in response to software control, of protecting high sensitivity receivers from high power, in-band, fast hopping signals. DESCRIPTION: On military platforms and in battle groups where many RF systems are collocated and share the same spectrum, co-site interference is often a severe problem. The arrival of in-band energy from some of our own transmitters effectively jams our receivers. Co-site interference will be an even worse problem in the future if wide band receivers are deployed to harvest the inherently more useful and affordable features of software radio. Such self-jamming is the RF equivalent of fratricide -- the victim systems usually turns off until the problematic signal goes away for self-protection, although in mild cases, they can continue to operate in a less sensitive mode by strongly reducing the signal gain in the receiver. It is highly desirable to have available a tunable filter that can reproducibly tune in less than 3 microseconds, center tune over relatively wide band ( >20% of band center frequency), introduce <0.5 dB insertion loss at the upper end of the band (assume 2 GHz center), and provide >60 dB of rejection at the band center in narrowest BW tuning configuration. Small physical size, band width selectable in the range 20% to 5%, and smooth phase gradients at the band edges may also be desirable. PHASE I: Develop a design concept and prove, at least by simulation, that a filter of the required characteristics can be constructed. PHASE II: Conduct at least 2 cycles of component design/fabrication/ and test that demonstrates that the design concept is valid and can be integrated with band pass filters. It is desirable to demonstrate both reproducibility of tuning and independent operation of multiple such filters in the same band and to measure their power handling characteristics. PHASE III: Insert such filters into the analog sections of wide band military receivers. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Such filters should have applicability in digital transmitters at the point where digital to analog signal conversion happens, assuming they have sufficient power handling characteristics to be low loss. They may also have applicability in commercial comms systems where spectral density is high so that active suppression of adjacent channels is critical to a given channel's utility. REFERENCES: 2. http://www.eecs.umich.edu/rebeiz/Current_Research.html#anchor335476 3. http://horology.jpl.nasa.gov/quantum/pub/ElectronicsLetters1.pdf KEYWORDS: tunable filters; analog filters; rapid tuning; equal phase filters; high Q filters TPOC: Deborah VanVechten
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