Digital radio link synthesized with a direct-division PLL at 22 GHz

A low-cost, effective and reliable radio subsystem, working in the 21.2-23.6-GHz band, is presented. Low cost has been achieved by integration of the RF head into a single microstrip assembly. The microstrip transmitter and receiver are described along with the direct-division phase-locked-loop (PLL) synthesizer circuit. The system's noise figure (12 dB) makes it possible to obtain a receiver sensitivity of -86 dBm with a 3.5-MHz filter and 2 FSK modulation. The values of output power and antenna gain permit an available system gain of 184 dB, which assures a transmission range of 10 km for a rainfall outage of less than 0.01% average per year for the worst Spanish weather conditions. >