Jeffrey A. Jargon

Complex permittivity determination from propagation constant measurements

The authors present 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. They use measurements in X-band waveguide to show that this technique compares well with the transmission/reflection and cylindrical cavity methods.

Characterization of broad-band transmission for coplanar waveguides on CMOS silicon substrates

This paper presents characteristics of microwave transmission in coplanar waveguides (CPWs) 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 /spl Omega//spl middot/cm to 12.5 /spl Omega//spl middot/cm. 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) deembedding 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.

Multiline TRL revealed

We reveal the techniques underlying actual implementation of the NIST MultiCal software, an evolved, automated implementation of the Multiline TRL (Thru-Reflect-Line) calibration method for vector network analyzers (VNAs). We describe the sequence of events in MultiCal for the Multiline TRL calibration and show how the program operates more like a state-machine than a solver of simultaneous equations. Our report details the steps used in estimating the transmission-line propagation-constant and the VNA correction coefficients.

Calibration Comparison Method for Vector Network Analyzers

We present a technique for comparing the scattering parameter measurements made with respect to two vector network analyzer calibrations. This method determines the worst-case measurement error bounds on any calibration from a benchmark calibration, assuming the two are similar to first order. We illustrate our method by examining the differences between an open-short-load-thru (OSLT) and a sliding load calibration, both of which are available commercially on a variety of vector network analyzers.

Applications of Artificial Neural Networks in Optical Performance Monitoring

Applications using artificial neural networks (ANNs) for optical performance monitoring (OPM) are proposed and demonstrated. Simultaneous identification of optical signal-to-noise-ratio (OSNR), chromatic dispersion (CD), and polarization-mode-dispersion (PMD) from eye-diagram parameters is shown via simulation in both 40 Gb/s on-off keying (OOK) and differential phase-shift-keying (DPSK) systems. Experimental verification is performed to simultaneously identify OSNR and CD. We then extend this technique to simultaneously identify accumulated fiber nonlinearity, OSNR, CD, and PMD from eye-diagram and eye-histogram parameters in a 3-channel 40 Gb/s DPSK wavelength-division multiplexing (WDM) system. Furthermore, we propose using this ANN approach to monitor impairment causing changes from a baseline. Simultaneous identification of accumulated fiber nonlinearity, OSNR, CD, and PMD causing changes from a baseline by use of the eye-diagram and eye-histogram parameters is obtained and high correlation coefficients are achieved with various baselines. Finally, the ANNs are also shown for simultaneous identification of in-phase/quadrature (I/Q) data misalignment and data/carver misalignment in return-to-zero differential quadrature phase shift keying (RZ-DQPSK) transmitters.

Extraction of conversion matrices for P-HEMTs based on vectorial large-signal measurements

We introduce a new technique which allows us to measure the admittance conversion matrix of a two port device, using a large-signal vector network analyzer. This method is applied to extract the conversion matrix of a 0.25 um PHEMT, driven by a 4.8 GHz signal, at different power levels, using an intermediate frequency of 600 MHz. A discussion of the up- and down-conversion is provided.

Establishing traceability of an electronic calibration unit using the NIST Microwave Uncertainty Framework

We present a method for establishing traceability of a commercial electronic calibration unit for vector network analyzers by characterizing the scattering parameters of its internal states with repeated multiline thru-reflect-line (TRL) calibrations and utilizing the NIST Microwave Uncertainty Framework to propagate uncertainties. With the electronic calibration unit characterized, we use it to calibrate a network analyzer, and characterize a number of verification devices with corresponding uncertainties. We also characterize the same verification devices using one of the previous multiline TRL calibrations, and compare results.

Equivalent Circuit Models for Coaxial OSLT Standards

We use a general description of transmission lines to develop analytic descriptions for offset OSLT (Open-Short-Load-Thru) standards used to calibrate vector network analyzers. We then formulate approximations for coaxial standards that implement the equivalent circuit parameters in common use. A comparison of calibrated verification device measurements demonstrates that our representations agree well with the models used in commercial instruments.

Repeatability study of commercial harmonic phase standards measured by a nonlinear vector network analyzer

In this paper, we present the first published repeatability study of commercial harmonic phase standards (HPS) measured by a nonlinear vector network analyzer. Specifically, we measure two harmonic phase standards, one of which is specified to 20 GHz and the other to 50 GHz. By performing 5 calibrations and making 100 measurements from 600 MHz to 19.8 GHz at each calibration, we determine the repeatability bounds for the complex wave-variable vectors and associated phases and magnitudes of each harmonic component. We also compare the mean phase values to those supplied by the manufacturer. While we achieve standard uncertainties of no greater than 0.73/spl deg/, we find significant variations in the mean values with changing HPS conditions and show evidence of a substantial thermal contribution.

Robust SOLT and alternative calibrations for four-sampler vector network analyzers

This paper assesses the accuracy of several proposed lumped-element calibration techniques for four-sampler vector network analyzers in the face of imperfectly defined standards. We find that these methods offer a wide range of accuracies, depending on the standards and how well they can be modeled. We introduce a new robust short-open-load-thru calibration that requires the same measurement and computational effort as traditional methods, but provides much better accuracy in transmission measurements and slightly better accuracy in reflection measurements.