Microwave-to-millimeter-wave synthesis chain phase noise performance.

We report on the phase noise measurement of a millimeter-wave synthesis chain developed for a continuous wave (CW) source exhibiting high frequency stability. We quantify the performance of each multiplication stage in terms of phase spectral purity. From the initial cryogenic sapphire oscillator generating 12.97 GHz, a total multiplication factor of eight is applied through two stages to reach a frequency of 103.75 GHz. We find that the chain performance is primarily limited by the phase noise of the initial frequency doubler.

Invited article: Dielectric material characterization techniques and designs of high-Q resonators for applications from micro to millimeter-waves frequencies applicable at room and cryogenic temperatures.

Dielectric resonators are key elements in many applications in micro to millimeter wave circuits, including ultra-narrow band filters and frequency-determining components for precision frequency synthesis. Distributed-layered and bulk low-loss crystalline and polycrystalline dielectric structures have become very important for building these devices. Proper design requires careful electromagnetic characterization of low-loss material properties. This includes exact simulation with precision numerical software and precise measurements of resonant modes. For example, we have developed the Whispering Gallery mode technique for microwave applications, which has now become the standard for characterizing low-loss structures. This paper will give some of the most common characterization techniques used in the micro to millimeter wave regime at room and cryogenic temperatures for designing high-Q dielectric loaded cavities.