A Composite Near-Field Scanning Antenna Range for Millimeter-Wave Bands
Authors: Doren W. Hess, John McKenna, Steve Nichols
Publication: AMTA 2004
Copyright Owner: NSI-MI Technologies
This paper describes a Composite Near-Field Scanning Antenna Range for frequency bands that extend from X-Band in the microwave frequency regime through W-Band in the millimeter-wave regime – i.e. 8.2 through 110 GHz. We show some of the initial checkout data using pyramidal standard gain horns and compare the patterns to theory.
A Low Cost and High Accuracy Optical Boresighting and Alignment System Using Video Cameras
Authors: John Demas, Quy Phan
Publication: AMTA 2004
Copyright Owner: NSI-MI Technologies
This paper describes a novel optical boresighting and
alignment system used to mechanically align antennas
on a compact antenna range at the North Island Naval
Air Depot in San Diego, CA. The antenna range has a
5-axis (roll/upper slide/azimuth/elevation/lower slide)
positioner used to measure various airborne antennas
for production testing. The video alignment system
implemented on this range uses two video cameras
outfitted with telephoto lenses, one on the roll stage
and the other on an antenna-mounting fixture. The
system has been demonstrated to yield an accuracy of
±0.005 degrees. Prior to the start of testing the
positioner is commanded to a “0” position and the
cameras focus on a fixed optical target to provide the
operator with a quick visual confirmation that the
positioner is accurately aligned prior to testing. The
video alignment system described has numerous
advantages over other mechanical alignment
techniques, is low cost, easy to use, and can be adapted
to a variety of testing configurations.
A Powerful Alternative for High Speed Near-Field of Far-Field Antenna Measurements
Copyright Owner: 2004 Horizon House Publications, Inc.
A high speed receiver and beam controller
has been introduced to address
the growing need for faster antenna
measurements. This article describes the Panther
6000 system and will show how it can
benefit the antenna range operator by allowing
more complex CW and pulsed antennas to
be tested in less time.
Many of today’s high performance antennas
are broadband, multi-beam, multi-port and
polarization-selective devices. Technology improvements,
including micro-electro-mechanical
system (MEMS) devices and novel adaptive
algorithms, are enabling increasingly complex
antennas for satellite communications,
radar, telecom, wireless and automotive applications.
New and complex architectures are
also being implemented, including adaptive
arrays, multiple-reflector and digital beamforming
antennas.
You have requested a Reprint of a Microwave Journal Paper
Copyright 2004 Horizon House Publications, Inc. Reprinted from icrowave Journal, January, 2004 Issue.
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Authors: John McKenna, David M. Kokotoff, Bjorn Widenberg
Publication: AMTA 2004
Copyright Owner: NSI-MI Technologies
The reflection coefficient of an antenna impacts the power transmitted by the antenna. Accurate characterization of this parameter is important in a communication or radar system. This paper discusses an implementation whereby a reflectometer is located near the antenna under test in an antenna range albeit far from the receiver. By placing the reflectometer near the antenna, the measurement uncertainty intrinsic to long cable runs can be minimized.
An Efficient and Highly Accurate Technique for Periodic Planar Scanner Calibration with the Antenna Under Test in Situ
Authors:Scott Pierce, Marion Baggett
Publication: AMTA 2004
Copyright Owner: NSI-MI Technologies
This paper describes the development, testing and evaluation of a new, automated system for calibration and AUT alignment of a planar near-field scanner that allows the calibration system to remain in place during AUT measurement and which can be used to support AUT alignment to the scan plane. During scanner calibration, probe aperture position measurements are made using a tracking laser interferometer, a fixture that positions the interferometer retro reflector at a precise location relative to the probe aperture and a probe roll axis that maintains the proper orientation between the retro reflector and the interferometer as the probe position is moved. Aperture scan path information is used to construct a best-fit scan plane and to define a Cartesian, scanner-based coordinate system. Scan path data is then used to build a probe position error map for each of the three Cartesian coordinates as a function of the nominal position in the scan plane. These error maps can be used to implement software-based corrections (K-corrections) or they may be used for active Z-axis correction during measurements. By using a set of tooling points on the antenna mount, an AUT coordinate system is measured with the interferometer. The system then directs an operator through a set of AUT adjustments that align the AUT with the planar near-field scanner to a desired accuracy. This paper describes the implementation and testing of the system on an actual planar scanner and AUT test environment, showing the improvement in effective scanner planarity.
Compact Range Rolled Edge Reflector Design Fabrication Installation and Mechanical Qualification
Authors:John R. Proctor, David R. Smith, Paul F. Martin, Gary A. Somers, Michael W. Shields, and Alan J. Fenn
Publication: AMTA 2004
Copyright Owner: NSI-MI Technologies
This paper describes the methodologies and processes used for the development, installation, alignment and qualification of a Compact Range Rolled Edge Reflector purchased by the MIT Lincoln Laboratory and installed at their test facility located at Hanscom Air Force Base. The Ohio State University, under contract to MIT Lincoln Laboratory, performed the electromagnetic design and analysis to determine the desired surface shape and required mechanical accuracy of various zones of that surface. The requirement for operation over a very broad frequency range (400 MHz to 100 GHz) resulted in a surface specification that was both physically large (24 ft × 24 ft) and included extremely tight tolerance requirements in the center section.
The mechanical design process will be described, including the generation of a solid “Master Surface” created from the “cloud” of data points supplied by The Ohio State University, verification of the “Master Surface” with The Ohio State University, segmentation of the reflector body into multiple panels, design, fabrication and factory qualification of the structural stands, panel adjustment mechanisms, and panels. Results of thermal cycling of the reflector panels during the fabrication process will be presented.
The processes used for installation of the reflector and the alignment of each panel to the “Master Surface” will be presented and discussed. Final verification of the surface accuracy using a tracking laser interferometer will be described. Color contour plots of the reflector surface will be provided, illustrating the final surface shape and verifying compliance to the surface accuracy requirement.
Design Considerations for Wireless Antenna Testing
Author:Donald G. Bodnar, Ph.D.
Publication: AMTA 2004
Copyright Owner: NSI-MI Technologies
This paper describes a new measurement system for testing antennas used in wireless communication system. A two-axis dielectric AUT positioner is used to reduce pattern perturbations, a vector network analyzer is employed for the receiver, and a broadband source antenna is utilized. RF test system design considerations are discussed including chamber design size. Software requirements that are unique to the needs of the wireless communication community are covered. The system is capable of making both far-field and spherical near-field measurements. A wide variety of antenna types can be tested using this system including handsets, laptop computers, and base station antennas.
