This letter presents a new transmission line method for measuring the complex permittivity of dielectric materials using propagation constant measurements. In contrast to previous methods, a network analyzer calibration is unnecessary since calibrated scattering parameters are not required. We use measurements in X-band waveguide to show that this technique compares well with the transmission/reflection and cylindrical cavity methods.

This paper presents characteristics of microwave transmission in coplanar waveguides (CPW's) on silicon (Si) substrates fabricated through commercial CMOS foundries. Due to the CMOS fabrication, the metal strips of the CPW are encapsulated in thin films of Si dioxide. Many test sets were fabricated with different line dimensions, all on p-type substrates with resistivities in the range from 0.4 1cm to 12.5 1cm. Propagation constant and characteristic impedance measurements were performed at frequencies from 0.1 to 40 GHz, using a vector-network analyzer and the through-reflect-line (TRL) deembeding technique. A quasi-TEM equivalent circuit model was developed from the available process parameters, which accounts for the effects of the electromagnetic fields in the CPW structure over a broad frequency range. The analysis was based on the conformal mapping of the CPW multilayer dielectric cross section to obtain accurate circuit representation for the effects of the transverse fields.

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The mission of the National Advanced Spectrum and Communications Test Network (NASCTN) is to provide, through its members, robust test processes and validated measurement data necessary to develop, evaluate and deploy spectrum sharing technologies that can increase access to the spectrum by both federal agencies and non-federal spectrum users.The U.S. Department of Commerce's National Institute of Standards and Technology (NIST) and National Telecommunications and Information Administration (NTIA) established the Center for Advanced Communications (CAC) in Boulder, Colorado, to address, among other challenges, the increasing need for spectrum sharing testing and evaluation capabilities to meet national needs. As part of CAC's mission to provide a single focal point for engaging both industry and other government agencies on advanced communication technologies, including testing, validation, and conformity assessment, NASCTN was formed under the umbrella of the CAC. NIST hosts the NASCTN capability at the Department of Commerce Boulder Laboratories in Boulder, Colorado. NASCTN is a membership organization under a charter agreement. Members• Make available, in accordance with their organization's rules policies and regulations, engineering capabilities and test facilities, with typical consideration for cost.• Coordinate their efforts to identify, develop and test spectrum sharing ideas, concepts and technology to support the goal of advancing more efficient and effective spectrum sharing.• Make available information related to spectrum sharing, considering requirements for the protection of intellectual property, national security, and other organizational controls, and, to the maximum extent possible, allow the publication of NASCTN test results.• Ensure all spectrum sharing efforts are identified to other interested members.Current charter members are:• National Telecommunications and Information Administration (NTIA)• National Institute of Standards and Technology (NIST)• Department of Defense Chief Information Officer (DoD CIO) AcknowledgmentsWe thank the Department of Defense and Space and Naval Warfare (SPAWAR) Systems Center Pacific for providing access to the measurement site at Point Loma; Michael Cotton and his colleagues at the National Telecommunications and Information Administration (NTIA), Institute for Telecommunications Sciences (ITS), Boulder, Colorado, for the use of the pre-selector; Frank Sanders at NTIA/ITS for sharing his expertise on radar systems and measurements; John Ladbury at NIST for characterizing the antennas we used in our measurements; and the NASCTN staff for stakeholder management, project management, and coordination.iii ______________________________________________________________________________________________________ This publication is available free of charge from: https://doi.org/10.6028/NIST. TN.1954 iv ______________________________________________________________________________________________________ This publication is available free of charge from: https://do...

This article describes how artificial neural networks (ANNs) can be used to benefit a number of RF and microwave measurement areas including vector network analysis (VNA). We apply ANNs to model a variety of on-wafer and coaxial VNA calibrations, including open-short-load-thru (OSLT) and line-reflect-match (LRM), and assess the accuracy of the calibrations using these ANN-modeled standards. We find that the ANN models compare favorably to benchmark calibrations throughout the frequencies they were trained for. We summarize other current applications of ANNs, including the determination of permittivities of liquids from the reflection coefficient measurements of an open-ended coaxial probe and the determination of moisture content of wheat from free-space transmission coefficient measurements. We also discuss some potential applications of ANN models related to power measurements, material characterization, and the comparison of nonlinear vector network analyzers.