COOLED FILTER LNA ASSEMBLY ENHANCES CELLULAR COVERAGE/

CRYOGENIC technology has long promised near-ideal conditions for high- frequency designers-conductors with almost no resistance or insertion loss. The technology has already been applied successfully to cellular and personal-communications-services (PCS) base stations as part of f ilter/low-noise-amplifier (LNA) assemblies operating at cryogenic temp eratures below 100 K. A practical evolution of this technology can be found in an innovative cross-coupled ceramic-filter/amplifier assembly from K&L Microwave (Salisbury, MD) with 100-W power-handling capabili ty and less than 0.5-dB insertion loss at a center frequency of 1883 M Hz. A six-stage design exhibits a 3-dB bandwidth of 4.5 MHz and a 40-d B bandwidth of 7.2 MHz. The noise figure (NF) of the integrated filter /LNA when cooled to 125 K is 0.71 dB.