In conventional phase noise metrology, the phase noise of an oscillator is measured by instruments equipped with specialized and sophisticated devices. Such hardware-based testing usually requires high-performance and costly apparatuses. In this paper, we carried out a novel phase noise measurement method based on a mathematical model. The relationship between the phase noise of a radio frequency oscillator and its power spectral density (PSD) was established, different components of the power law phase noise were analyzed in the frequency domain with their characteristic parameters. Based on the complete physical model of an oscillator, we fitted and extracted the parameters for the near-carrier Gaussian and the power law PSD with Levenberg-Marquardt optimization algorithm. The fitted parameters were used to restore the power law phase noise with considerable precision. Experimental validation showed an excellent agreement between the estimation from the proposed method and the data measured by a high-performance commercial instrument. This methodology can be potentially used to realize fast and simple phase noise measurement and reduce the overall cost of hardware.

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The main purpose of industrial nondestructive testing (NDT) is to diagnose the stability, reliability and failure probability of materials, components and structures. Industrial component mechanical strength is one of the most important properties NDT is used to characterize. Subtle but perceptible changes in stress-strain behavior can be reliable indicators of defect formation. A detailed review on the state-of-the-art NDT methods using optical-radiation, photoacoustic, and photothermal techniques for mechanical strength evaluation and defect pre-diagnosis is presented in this article. Mechanical strength is analyzed in terms of the deformation/strain field, the stress-strain relation, and the residual stress in an elastic material subjected to tensile or compressive loading, or impact. By introducing typical NDT experiments, the history and features of each methodology are revisited and typical applications are discussed. This review also aims to be used as a reference toward further research and development of NDT technologies characterizing mechanical strength of materials and components.

In this article, we proposed a noncontact testing scheme for micrometer to sub-micrometer level ultrasonic vibration mainly generated by laser ultrasound upon the novel utilization of near-field microwaves. The measurement was performed based on a Ku-band near-field resonator-probe, which was optimized to perceive the low amplitude out-of-plane vibration in the ultrasonic range. A near-field electromagnetic measurement theory was established to help analyze the sensitivity and responsivity of the resonator-probe outfit. The electric field parameters were extracted with respect to the port based on a lumped-circuit model, which was further validated using a finite-element model. Experiments were carried out with respect to a piezoelectric ceramic disk designed to generate vibrations of desired amplitude, which is compatible to that in laser ultrasonic testing. The accuracy of the technique was assessed by comparing with the laser vibrometer measurement results. It was verified that the proposed near-field microwave probe can achieve considerable accuracy in perceiving sub-micrometer ultrasonic vibration up to 180 kHz.