Unmanned aerial vehicles (UAVs) are performing a growing number of duties for the U.S. armed forces with key missions in surveillance, electronic counter measures (ECM), and electronic warfare (EW). To complete these tasks, especially for video surveillance, military UAVs must be equipped with wideband communications systems capable of reliable high-altitude performance, although combinations of fast tuning speeds of low noise are not common in RF/microwave synthesizers. Fortunately, the RS-1000 Series of ruggedized frequency synthesizers from FEI-Elcom Tech has been designed to handle altitudes as high as 70,000 ft. for a wide range of airborne applications. They measure just 3 × 3 × 1 in. and weigh just 0.75 lb. in support of ever-shrinking military UAVs.
These single-loop phase-locked frequency synthesizers are available from 1 to 23 GHz in bands as wide as 25%. They are something of a rarity in RF/microwave signal sources because they tune in 1-, 5-, or 10-MHz steps with switching speed of 50 μs, yet they also achieve low noise phase of typically −110 dBc/Hz offset 10 kHz from a 10-GHz carrier, −102 dBc/Hz offset 1 MHz, and −145 dBc/Hz offset 10 MHz from the carrier. They boast harmonic levels of −40 dBc or better and spurious levels of −77 dBc or better for effective ECM applications requiring generation of “false” signals imitating a threat source. The 50-Ω frequency synthesizers have typical output return loss of 15 dB.
The compact frequency synthesizers are built for the skies: They are hermetically sealed and conduction cooled to ensure continuous operation at high altitudes, whether in UAVs or in satellite-communications (satcom) systems. They can handle high vibration levels but are also well suited for ground-based spread-spectrum communications and radar systems requiring fast switching microwave signals with low noise content. They can handle operating temperatures from −54 to +85°C.