- 演講: Prof. Jeremy Everard - Low Phase Noise Signal Generation utilising Oscillators, Resonators & Filters and Atomic Clocks
- 發佈單位：mtt17支會 原始連結
講題：Low Phase Noise Signal Generation utilising Oscillators, Resonators & Filters and Atomic Clocks
講者：Prof. Jeremy Everard
Jeremy Everard obtained his degrees from King’s College London and the University of Cambridge, UK in 1976 and 1983 respectively. He worked for six years in industry at GEC Marconi Research Laboratories, M/A-Com and Philips Research Laboratories on Radio and Microwave circuit design. At Philips he ran the Radio Transmitter Project Group. He became full Professor of Electronics at the University of York in September 1993. He has taught analogue IC design, optoelectronics, filter design, Electromagnetism and RF & microwave circuit design. In September 2007, he was awarded a five-year research chair in Low Phase Noise Signal Generation sponsored by BAE Systems and the Royal Academy of Engineering. In the RF/Microwave area his research interests include: The theory and design of low noise oscillators; flicker noise measurement and reduction high efficiency broadband amplifiers; high Q printed filters with low radiation loss and broadband negative group delay circuits.
This talk will initially discuss the theory and design of a wide variety of oscillators offering the very best performance. Typically, this is achieved by splitting the oscillator design into its component parts and developing new amplifiers, resonators and phase shifters which offer high Q, high power handling and low thermal and transposed flicker noise. Key features of oscillators offering the lowest phase noise available will be shown, for example: a 1.25GHz DRO produces -173dBc/Hz at 10kHz offset and a noise floor of -186dB and a 10 MHz crystal oscillator shows -123dBc/Hz at 1Hz and -149 at 10Hz. New compact atomic clocks with ultra-low phase noise microwave synthesiser chains (with micro Hz resolution) will also be briefly described to demonstrate how the long-term stability can be improved. New printed resonators (and thereby filters) demonstrate Qs exceeding 540 at 5GHz on PCBs and > 80 at 21GHz on GaAs MMICs. These resonators produce near zero radiation loss and therefore require no screening. L band 3D printed resonators demonstrate high Q (> 200) by selecting the standing wave pattern to ensure zero current through the via-hole and new ultra-compact versions (4mm x 4mm) have been developed for use inside or underneath the package. Alumina based resonators demonstrating Qs >200,000 at X band have also been produced. Tuneable versions (1%) have recently been developed. The next generation of oscillators will offer orders of magnitude improvement in performance. Our current attempts to do this will be described.