Abstract :
A phase-locked GaAS FET oscillator serves as a broadband power amplifier and, at the same time, as an up-converter for the transmission of FM signals in microwave radio links. A new measurement method, using a combination of load-pull and reflection test to determine the large-signal parameters of the GaAS FET, enables a simple but exact design of a power VCO. The PLL up-converter was designed at 5 (and 7) GHz with an output power of 400 (800) mW and an automatic tuning range of 14 (6)%. The test results show the possibilities and limits of this transmitter principle for both analog and digital microwave communications systems.
