Roger B. Marks

IEEE standard 802.16: a technical overview of the WirelessMAN/sup TM/ air interface for broadband wireless access

The broadband wireless access industry, which provides high-rate network connections to stationary sites, has matured to the point at which it now has a standard for second-generation wireless metropolitan area networks. The IEEE standard 802.16, with its WirelessMAN/sup TM/ air interface, sets the stage for widespread and effective deployments worldwide. This article overviews the technical medium access control and physical layer features of this new standard.

Characteristic impedance determination using propagation constant measurement

A method by which the characteristic impedance of transmission lines may be easily determined from a measurement of the propagation constant is demonstrated. The method is based on a rigorous analysis using realistic approximations to account for the effects of imperfect conductors. Numerical studies which indicate that high accuracy is possible are discussed. Experiments using a coplanar waveguide which demonstrate a significant improvement in the measurement of S-parameters are described.<<ETX>>

A General Waveguide Circuit Theory

This work generalizes and extends the classical circuit theory of electromagnetic waveguides. Unlike the conventional theory, the present formulation applies to all waveguides composed of linear, isotropic material, even those involving lossy conductors and hybrid mode fields, in a fully rigorous way. Special attention is given to distinguishing the traveling waves, constructed with respect to a well-defined characteristic impedance, from a set of pseudo-waves, defined with respect to an arbitrary reference impedance. Matrices characterizing a linear circuit are defined, and relationships among them, some newly discovered, are derived. New ramifications of reciprocity are developed. Measurement of various network parameters is given extensive treatment.

Comparison of On-Wafer Calibrations

A powerful new verification technique determines the measurement accuracy of scattering parameter calibrations. The technique determines the relative reference impedance, reference plane offset, and the worst-case measurement deviations of any calibration from a benchmark calibration. The technique is applied to several popular on-wafer scattering parameter calibrations, and the deviations between those calibrations and the thru-reflect line calibration are quantified.

Transmission line capacitance measurement

The capacitance of coplanar lines is measured with two new techniques, one utilizing the resistance of the line and the other that of a resistor embedded in the line. The results of both measurements agree closely with calculations. A technique for directly comparing the capacitances of two similar transmission lines is also demonstrated. The relevance of these measurements to the determination of characteristic impedance is discussed.<<ETX>>

Accurate transmission line characterization

A method for the characterization of transmission lines fabricated on lossy or dispersive dielectrics is introduced. The method, which is more accurate than conventional techniques, is used to examine the resistance, inductance, capacitance, and conductance per unit length of coplanar waveguide transmission lines fabricated on lossy silicon substrates.<<ETX>>

Formulations of the Basic Vector Network Analyzer Error Model including Switch-Terms

This paper explores details of the relationship between two expressions of the basic error model describing a two-port vector network analyzer (VNA). One of these formulations is the conventional twelve-term formulation; the other is in terms of error boxes. The paper focuses on the role of the switch terms. By fully detailing the relationship between the two formulations, the paper arrives at several significant new results, including an explicit constraint on the parameters of the twelve-term model.

LRM probe-tip calibrations using nonideal standards

The line-reflect-match (LRM) calibration is enhanced to accommodate imperfect match standards and lossy lines typical of monolithic microwave integrated circuits. We characterize the match and line standards using an additional line standard of moderate length. The new method provides a practical means of obtaining accurate, wideband calibrations with compact standard sets. Without the enhancement, calibration errors due to imperfections in typical standards can be severe. >

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.

A Complete Multimode Equivalent-Circuit Theory for Electrical Design

This work presents a complete equivalent-circuit theory for lossy multimode transmission lines. Its voltages and currents are based on general linear combinations of standard normalized modal voltages and currents. The theory includes new expressions for transmission line impedance matrices, symmetry and lossless conditions, source representations, and the thermal noise of passive multiports.