Propagating Measurement Uncertainty to Microwave Amplifier Nonlinear Behavioral Models
    We propagate for the first time correlated measurement uncertainties into a nonlinear behavioral model of a millimeter-wave amplifier. We make use of the National Institute of Standards and Technology Microwave Uncertainty Frameworkto evaluate the uncertainties in large-signal electromagnetic wave measurements of an amplifier, followed by the extraction of X-parameters using an industry standard algorithm. This extracted model is included as a component in a circuit simulator to evaluate gain …
    Evaluating residual errors in waveguide VNAs from microwave to submillimetre-wave frequencies
    Vector network analysers (VNAs) are used extensively for measurements that are made at frequencies ranging from a few kilohertz to at least one terahertz. At radio and microwave frequencies, there are well-established methods for assessing the quality and confidence of these measurements, when they are made in coaxial lines. These methods are usually based on determining the size of residual errors that remain in the VNA after calibration. To date, the performance of these methods has not been …
    Comparing methods for evaluating measurement uncertainty given in the JCGM `Evaluation of Measurement Data' documents
    The Joint Committee for Guides in Metrology (JCGM) publishes and maintains reference documents relating to general aspects in metrology. Working Group 1 of the JCGM is responsible for the Evaluation of Measurement Data series of documents that gives information for evaluating and expressing uncertainty in measurement. This paper compares several methods for evaluating measurement uncertainty that are described in these documents. Emphasis is given to situations where more than one input quantity …
    An Interferometric Characterisation Technique for Extreme Impedance Microwave Devices
    This paper presents a microwave impedance characterization technique for extreme impedance devices. The method is based on active interferometry and uses a 2-source 4-port vector network analyzer, which allows for a compact and straight-forward implementation. A new calibration algorithm is described that incorporates error terms from two separate three-known-load calibrations. Based on simulated and measured data, the proposed technique shows substantial improvement in obtaining the impedance …
    Overview of Superconducting RF Cavity Reliability at Diamond Light Source
    Diamond Light Source has been providing beam for users since January 2007. The electron beam in the storage ring is normally driven by two superconducting CESR-B cavities, with two similar cavities available as spares. Day-to-day reliability of the cavities, measured by storage ring MTBF, has improved enormously over the years. A full analysis of how this improvement has been achieved is given, with particular attention paid to cavity voltage and vacuum pressure management, and the scheduling …
    Leveraging Internet of Things Developments for Rapid Prototyping of Synoptic Displays
    Recently the technology industry has been laying foundations for the eponymous Internet of Things (IoT): efficient publish-subscribe protocols; process control schemas for household items; and improved low-power radio communications. Accelerator controls and IoT have several aspects in common - small payloads, low latency, dashboard/synoptic data presentation format are some examples. The IoT now provides several open-source projects which can provide a partial implementation of one or more …
    An Inter-Laboratory Comparison of NVNA Measurements
    A comparison of nonlinear vector network analyser (NVNA) measurements has been carried out involving four organisations (National Physical Laboratory, UK, University of Surrey, UK, Chalmers University of Technology, Sweden and Keysight Technologies, Denmark). Three nonlinear devices consisting of two amplifiers and a nonlinear verification device (NLVD) were measured by each of the organisations. Results are presented which show generally good agreement between the measurements and give some …
    Evaluating residual errors in waveguide network analysers from microwave to submillimetre-wave frequencies
    Vector Network Analysers (VNA) are used extensively for many types of measurement that are made at frequencies ranging from a few kilohertz to at least one terahertz. At radio and microwave frequencies, there are well-established methods for assessing the quality and integrity of these measurements, when they are made in coaxial lines. These methods are usually based on determining the size of residual errors that remain in the VNA after calibration. However, to date, the performance of these …