Low-Noise Microwave Resonator-Oscillators: Current Status and Future Developments

Abstract

Abstract. This contribution is devoted to principles of operation and design of low noise electromagnetic oscillators. We begin this chapter by introducing the concept of oscillator frequency stability and discussing both time and frequency domain approaches to its characterisation. We review most common experimental techniques used for improving the oscillator frequency stability. A particular attention is paid to applications of microwave circuit interferometry to precision measurements of oscillator frequency fluctuations. Finally, we analyse the future trends in the design of low noise microwave oscillators. This includes (i) interferometric suppression of oscillator power fluctuations and (ii) reduction of the oscillator frequency-temperature dependence by making use of an anisotropy of sapphire dielectric resonators.

Noise Suppression With Cryogenic Resonators

“…5 is the computed result. A small discrepancy between the calculated and measured data at F > 30 kHz is due to the numerical model's limitations to calculate the NSF [20]. As mentioned earlier, two cryogenic SLC resonators were characterized both in terms of their transmission coefficients and noise suppression factors.…”

Development and measurement of 10 GHz oscillators with ultra‐low phase noise

“…They are crucial devices in modern telecommunication engineering and military applications. Advances in the reduction of phase noise and amplitude noise in microwave oscillators has enabled the development of high-resolution Doppler radars capable of making aircraft safer through the detection of hazardous air turbulences [2]. Apart from commercial and military uses, recently microwave oscillators with ultra-low phase have been envisioned for applications in experimental physics in the detection of gravitational waves.…”

“…The design practice to realize ultrawide bandwidth is to generate multiple resonances and match them using appropriate techniques. In monopole radiators, step or exponential impedance inverters realized with ground and patch minimize the insidious reflections and radiate the guided signals [1][2][3]. There are many approaches to design a slot antenna with ultrawide bandwidth.…”