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Search Publications by: Ronald Wittmann (Assoc)

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Displaying 1 - 25 of 79

Near-Field, Spherical-Scanning Antenna Measurements With Nonideal Probe Locations

October 12, 2021
Author(s)
Ronald C. Wittmann, Bradley Alpert, Michael H. Francis
We introduce a near-field, spherical-scanning algorithm for antenna measurements that relaxes the usual condition requiring data points to be on a regular spherical grid. Computational complexity is of the same order as for the standard (ideal-positioning)

A Possible Advantage of Using Bi-directional S-Parameters in Antenna Measurements

November 30, 2018
Author(s)
Alex Yuffa, Ronald C. Wittmann, Michael H. Francis, Josh Gordon, David R. Novotny
the unknown-thru calibration technique is being used to achieve a system level calibration at milli-meter frequencies (>50 GHz) on the robotic ranges at NIST. Since this requires the use of a full bi-directional measurement, which takes longer than

Characterization of Millimeter-wave 3D-printed Antennas For CubeSat Applications Using a Robotic Antenna Range

February 21, 2017
Author(s)
Joshua A. Gordon, David R. Novotny, Ronald C. Wittmann, Michael H. Francis, Jeffrey R. Guerrieri, Alexandra Curtin, Miranda L. Butler, Albin Gasiewski, Lavanya Periasamy
3D printing is finding applications across many areas and may also be a useful technology for antenna fab- rication for CubeSats. However, the quality of an antenna produced using 3D printing must be well understood if this technology can be relied upon

Assessment of a 3D-Printed Aluminum Corrugated Feed Horn at 118.7503 GHz

February 19, 2017
Author(s)
Josh Gordon, David R. Novotny, Ronald C. Wittmann, Michael H. Francis, Jeffrey R. Guerrieri, Periasamy Lavanya, Albin Gasiewski
All-metal 3D printing is investigated as a viable option for millimeter wave applications. 3D printing is finding applications across many areas and may be a useful technology for antenna fabrication. The ability to rapidly fabricate custom antenna

Gain Comparison of a 3D?Printed Horn and an Electroformed Horn

October 29, 2016
Author(s)
Michael H. Francis, David R. Novotny, Josh Gordon, Alexandra Curtin, Ronald C. Wittmann
The National Institute of Standards and Technology (NIST) has used the three‐antenna extrapolation method to determine the on‐axis gain of several antennas in the WR8 frequency band. One antenna is an electroformed μ=±1 probe with gain of about 9 dB. The

Multi-purpose Configurable Range for Antenna Testing Up To 220 GHz*

April 9, 2016
Author(s)
David R. Novotny, Michael H. Francis, Ronald C. Wittmann, Josh Gordon, Jeffrey R. Guerrieri, Alexandra Curtin
NIST has developed a multi-purpose test range for performing several types of antenna testing including spherical, cylindrical and planar near-field scanning as well as extrapolation measurements. This range uses a commercial, offthe- shelf, six-axis robot

Millimeter-Wave Near-Field Measurements Using Coordinated Robotics

December 1, 2015
Author(s)
Joshua A. Gordon, David R. Novotny, Ronald C. Wittmann, Michael H. Francis, Miranda L. Butler, Jeffrey R. Guerrieri
The National Institute of Standards and Technology(NIST) recently developed a new robotic scanning system for performing near-field measurements at millimeter-wave (mm-wave)frequencies above 100 GHz, the configurable robotic millimeterwave antenna (CROMMA)

Millimeter-Wave Near-Field Measurements Using Coordinated Robotics

October 29, 2015
Author(s)
Joshua A. Gordon, David R. Novotny, Michael H. Francis, Ronald C. Wittmann, Alexandra Curtin, Miranda L. Butler, Jeffrey R. Guerrieri
The National Institute of Standards and Tech- nology (NIST) recently developed a new robotic scan- ning system for performing near-field measurements at millimeter-wave frequencies above 100 GHz, the CROMMA (Configurable Robotic Millimeter-Wave Antenna)

Antenna Measurement Implementations and Dynamic Positional Validation Using a Six Axis Robot

October 11, 2015
Author(s)
David R. Novotny, Josh Gordon, Michael H. Francis, Ronald C. Wittmann, Alexandra Curtin, Jeffrey R. Guerrieri
We have performed spherical and extrapolation scans of two antennas at 118 GHz using a commercial 6-axis robot. Unlike spherical scanning, linear extrapolations do not precisely conform to the native circular movement of the individual robot axes. To

Consensus Value Method to Compile On-Axis Gain Measurement Results

October 10, 2015
Author(s)
Jeffrey R. Guerrieri, Michael H. Francis, Ronald C. Wittmann
This paper shows that a consensus value method can be used to compile on-axis gain measurement data that have a large range of values and uncertainties. A variety of methods are used to analyze multiple data sets such as un-weighted averages, weighted

Generalized Probe-Position Compensation Methods for Near-Field Antenna Measurements

October 10, 2015
Author(s)
Michael H. Francis, Ronald C. Wittmann, Josh Gordon, David R. Novotny
The National Institute of Standards and Technology (NIST) has developed computationally efficient algorithms for probe location and polarization compensation in near- to far-field transformations for use when measurements are not made on the standard

Robotic Spherical Near-Field Measurements at 183 GHz

July 21, 2015
Author(s)
Michael H. Francis, Ronald C. Wittmann, David R. Novotny, Joshua A. Gordon
We describe millimeter-wave near-field measurements made with the new National Institute of Standards and Technology (NIST) robotic scanning system. This system is designed for high-frequency performance, is capable of scanning in multiple configurations

Configurable Robotic Millimeter-Wave Antenna Facility

April 13, 2015
Author(s)
Jeffrey R. Guerrieri, Joshua A. Gordon, David R. Novotny, Michael H. Francis, Ronald C. Wittmann, Miranda L. Butler
This paper introduces the Configurable Robotic Millimeter-Wave Antenna (CROMMA) facility by the Antenna Metrology Lab at the National Institute of Standards and Technology (NIST). NIST set out to develop an antenna measurement facility that would be

Evaluating and Verifying the Performance of the Ft. Huachuca Compact Range

July 6, 2014
Author(s)
Michael H. Francis, Ronald C. Wittmann
The National Institute of Standards and Technology (NIST) presents a plan for evaluating and verifying the performance of the refurbished Ft. Huachuca Antenna Test Facility outdoor compact range. This plan was drawn up based upon information supplied to

Evaluating the Performance of the Ft. Huachuca Compact Range

July 6, 2014
Author(s)
Michael H. Francis, Ronald C. Wittmann
The National Institute of Standards and Technology (NIST) presents a plan for evaluating and verifying the performance of the refurbished Ft. Huachuca Antenna Test Facility outdoor compact range. This plan was drawn up based upon information supplied to

Sensitivity of Probes in Near-Field Spherical-Scanning Antenna Measurements

July 7, 2013
Author(s)
Ronald C. Wittmann, Michael H. Francis
We define and calculate sensitivity for several actual and simulated probes. Probe sensitivity can have a significant impact on measurement uncertainty associated with probe deconvolution in near- field, spherical scanning, antenna measurements.

Using Truncated Data Sets in Spherical Scanning Antenna Measurements

February 8, 2012
Author(s)
Ronald C. Wittmann, Carl F. Stubenrauch, Michael H. Francis
We discuss the mitigation of truncation errors in spherical scanning measurements. The main emphasis is the spherical harmonic representation of probe transmitting and receiving functions; however, our method is applicable to near-field measurement of

Near-Field Spherical Scanning: Quiet-Zone Field Evaluation

June 1, 2009
Author(s)
Randy Direen, Michael H. Francis, Ronald C. Wittmann
Spherical near-field scanning measurements are used to determine the incident electromagnetic fields within a test volume. Results from two independent approaches are compared and found to agree within estimated uncertainties.

Near-Field Spherical Scanning: Uncertainties in Test-Zone Field Measurements

November 16, 2008
Author(s)
Randy Direen, Ronald C. Wittmann, Michael H. Francis
The electromagnetic field within a test volume can be measured using spherical scanning techniques. Characterization of the field within the sphere requires compensation for probe-pattern effects. We provide a simple uncertainty analysis to estimate

Chamber Imaging Using Spherical Near-Field Scanning

July 5, 2008
Author(s)
Ronald C. Wittmann, Michael H. Francis, Randy Direen
We discuss recent measurements performed at the National Institute of Standards and Technology (NIST) that were used to characterize the incident fields within a test volume and to produce images of the test chamber.

Near-field Scanning Measurements: Theory and practice

July 3, 2008
Author(s)
Michael H. Francis, Ronald C. Wittmann
This chapter summarizes theoretical and practical aspects of near-field scanning methods. These methods allow complete characterization of the transmitting or receiving properties using measurements made in close proximity to an antenna.

ANTENNA TEST RANGE IMAGING USING SPHERICAL NEAR-FIELD SCANNING

June 8, 2008
Author(s)
Michael H. Francis, Ronald C. Wittmann, Randy Direen
Although the theory is straightforward, practical implementation of spherical near-field scanning for evaluating test chambers presents some significant challenges. Among these are the selection of an appropriate probe and the difficulty in minimizing