Thermal characterization of a microwave generator and its effects on the frequency stability

Phase Locked Loops (PLL)-based microwave generators are highly stable and such a parameter depends strongly on the stability of the reference oscillator and on the stability of the loop filter. In this work a 2.4 GHz microwave generator has been and integrated in our laboratory, using commercial components and devices. The generator has been characterized on its parameters of signal purity, phase noise and frequency stability. Additionally, frequency stability is affected by temperature variations and the maximum thermal frequency drift is an important figure of the generator performance. The thermal performance of microwave oscillators is not often provided by the manufacturers. The frequency stability of our microwave generator has been measured in 0-40 °C range and a 2 KHz frequency drift has been found at 40°C.