Wide Pass Bandwidth, High Selectivity, Continuously Tunable Notch Filters

SBIR topic DAF27BZ02-DV025 (U.S. Department of Defense – Air Force), Phase I and II. Open to U.S. small businesses. Opens: December 2, 2026. Closes: January 6, 2027. The objective of this topic is to develop miniature, low power, and high selectivity tunable notch filters capable of protecting wideband receivers from large interferers. The effort will target the largest interferers which are in L, S, C, and X bands with tunable notch filters, while allowing pass bandwidths spanning L through Ku bands. Each notch filter must be continuously tunable across a minimum of 3 of the 4 targeted bands (L, S, C, and X) while having a notch depth > 20 dB and a notch bandwidth < 1 % across all tuned frequencies. With a narrow notch bandwidth, each notch filter must be programmable and maintained with an accuracy of 50% of the notch bandwidth and should maintain this accuracy over temperature. The notch filters must be able to reject large interfering signals and therefore should be able to notch receive interference levels greater than 5 dBm. In the bandpass each filter must cover L-Ku band (1-18 GHz) while maintaining a low insertion loss and noise figure of less than 1.5 dB and low passband distortion with an IIP3 > +50 dBm. Each notch filter must be small, less than 3 cc, and should be connectable in series without interfering with one another to notch multiple frequencies in the same receive chain. Finally, the power consumption, including any tuning electronics, of each notch filter should be less than 100 mW. The required metrics are: Passband frequency range (GHz)1 – 18 Maximum passband insertion loss or noise figure (dB) ≤ 1.5 Passband IIP3 (dBm)≥ 50 Notch band tunable frequency range (GHz)1 – 12 Number of bands covered by a single, continuously tunable notch≥ 3 Minimum notch depth across all tuned notch states (dB)≥ 20 Maximum notch fractional bandwidth (%)≤ 1Size (cc)≤ 3 Power consumption (mW)≤ 100 Official solicitation: https://www.dodsbirsttr.mil/topics-app/