Microwave balanced oscillators and frequency doublers

The research presented in this thesis is on the application of the injection-locked oscillator technique to microwave balanced oscillators. The balanced oscillator design is primarily analysed using the extended resonance technique. A transmission line is connected between the two active devices, so that the active device resonate each other. The electrical length of the transmission line is also analysed for the balanced oscillation condition. The balanced oscillator can be viewed with the negative resistance model and the feedback model. The former model is characterised at a circuit plane where the feedback network is cut. By using both the negative-resistance oscillator model and the feedback model, the locking range of the oscillator is analysed by extending Kurokawa's theory. This analysis demonstrates the locking range of the injection phenomenon, where the injection frequency is either close to the free-running frequency, close to (1/n) x free-running frequency or close to n x the free-running frequency. It also reveals the effect of different injection power levels on the locking range. Injection-locked balanced oscillators for subharmonic and fundamental modes are constructed. When the balanced oscillator is in the locking state, it is clearly shown that the output signal is better stabilised and the phase noise is attenuated. The experimental results agree with the analysis. Furthermore, the spurious signal suppression in a cascaded oscillator is investigated. The other focus of this research is on the design of frequency doublers. A balanced doubler is designed and integrated with a balanced injection-locked oscillator. The experimental result shows that the output signal is clean and stabilised. The other important frequency doubler design technique studied is the use of the feedforward technique to significantly eliminate the fundamental frequency component. The design and the experiment show that the fundamental component can be suppressed to better than 50 dBc. (author)Available from British Library Document Supply Centre- DSC:DXN057604 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo