Oewaves

INVENT. DEVELOP. DELIVER.

Filters

Fast reconfigurable filters of large order are a key element in high Spur-Free-Dynamic-Range (SFDR) RF receivers needed for SIGINT (Comint, Elint), EW, Radar, GMTI/AMTI and other applications. These applications require sensing and processing of signals over channel widths of less than 10 KHz to greater than 100 MHz on RF carriers of frequencies in the range of 2-20 GHz. Equivalent SFDR require 130 to over 150 dB-Hz2/3. Dynamic range values of 60 dB over channel widths of 50 MHz are modest goals in the face of such needs. These filter passbands must also provide high out of band rejection with low in band insertion loss to be compatible with the high SFDR and be reconfigurable in times less than a micro-second to accommodate changing targets and battlefield conditions. Furthermore, the platforms are often small, power limitations are severe, and platform environments are difficult requiring decades of unattended operation.To meet these stringent requirements, OEwaves has extended its micro-resonator technology and demonstrated a 3-pole filter with less than 4 dB of insertion loss tunable over 12 GHz in an earlier DARPA program, AOSP. The filter had a 3 dB bandwidth of less than 17 MHz, with a Butterworth 3rd order function. In a subsequent step, a five-pole wideband tunable filter was demonstrated. As shown in the figure below, this filter has a 600 MHz pass band with an out of band rejection of 75 dB at 2 GHz away from the center frequency. The filter can be tuned readily across 2-20 GHz and is capable of as much as 1 THz. Small, sub-microsecond tuning speed with extreme agility are key features of OEwaves' microwave-photonic filters.