AMTA Paper Archive


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AMTA Paper Archive

Dual Compact Range for Bistatic Signature Exploitation
R.A. Marr,U.H.W. Lammers, November 1998

We are developing a new indoor bistatic measurement technique for scale model targets. This procedure will collect far-field data at bistatic angles from 60° to nearly 180° and near-field data over a 10' high, 10' radius cylinder surrounding the target. A stationary parabolic reflector illuminates the target while a duplicate parabolic reflector, rotated to its bistatic position, acquires far-field data. The independent, concentrically mounted near-field scanner gathers comparison data. Most compact range reflectors employ shaped edges to avoid edge diffracted signals entering the measurement volume. We report results of using shaped absorber material over otherwise unmodified reflector edges to reduce diffraction. High-resolution 3D images of sample structures demonstrate the practicality of this approach.

Moment Method Inter-code Comparisons and Angular Sensitivity Studies for NIST Calibration (Squat) Cylinders
B.E. Fischer,B.M. Kent, B.M. Welsh, T.M. Fitzgerald, W.D. Wood, November 1998

Considerable attention has been given recently to the problem of properly calibrating RCS measurements. Traditionally accepted approaches utilize aluminum spheres for ease of placement (insensitivity to orientation) and availability of computationally accurate (Mie series) solutions. In many situations, however, it can be shown that spheres fail as calibration devices. Past AMTA presentations [1, 2, 3] have shown that required mechanical tolerances for spheres are stringent, and can be difficult to achieve. Furthermore, energy can be bistatically reflected from spheres into column or pylon target supports, adding to calibration contamination. One solution may be a more wide-spread introduction of squat cylinders as calibration devices. Outdoor ranges have utilized squat cylinders for years for many of the aforementioned reasons. Advantages and disadvantages exist as always. The reduction of target­ support interaction and improved mechanical tolerances may be offset by difficulty in providing computationally accurate cylinder predictions and proper cylinder orientation. This work attempts to straightforwardly illustrate how these considerations come into play to assist the range engineer in determining how best to proceed to calibrate his or her data.

Multifunctional Anechoic Chamber for Near/Far Field Antenna Measurement and EMC/EMI, A
B. Kwon,C-K Kang, J-T Ihm, J-W. Kim, S-J Kim, November 1998

Due to the high cost of constructing anechoic chamber, the multi-usage of a chamber in various applications is very effective in terms of cost as well as space. In this paper, we describe an anechoic chamber, currently used at SK Telecom in Korea. This is designed for the measurements of both far/near field antenna and EMC/EMI in the identical chamber. This anechoic chamber and measurement system support antenna test in the frequency range of 150 MHz to 40 GHz and satisfy the requirement of ANSI C63.4 and CISPR16.1for EMC/EMI. The near field measurement system supports planar, cylindrical and spherical methods to test various types of antennas. For the far field and EMC/EMI measurement, the planner near field scanner is hidden by movable absorber wall. The AUT positioner is foldable and can be stored under the chamber floor. Brief description of the chamber and the measurement system with measured results are also provided.

Consideration in Relocating a Satellite Antenna Test and Repair Facility
T.J. Ondrey,J. Freidel, R.B. Keyser, November 1998

The maintenance, test and repair workload for the Air Force MSQ-118 satellite ground-based The current MSQ-118 work requires the support of four maintenance shops and a planar near-field certification range. About one dozen employees maintain and test 148 phased-array antennas, each containing thousands of components, including radio-frequency (RF) stripline and microelectronics circuitry. This paper will detail the planning and start of the relocation of the antenna repair and test facilities.

Relocation of RCS Measurement Facility Sycamore Canyon Site A Poway, CA to Tucson, AZ and the Techniques used for Measurement Capability Validation
L.L. Mandeville,D.J. McCann, J.A. Ference, S.G. Cox, November 1998

In the process of relocating an RCS range from Sycamore Canyon, Poway, CA to the Raytheon Systems Company plant site in Tucson, AZ, the very important question of measurement validation had to be addressed. This relocation has to be accomplished on a very aggressive schedule in order to keep the impact to measurement schedules at a minimum. A high standard of measurement capability had to be retained. The aggressive relocation schedule poses risks to site selection and subsequent range validation. We will present an outline of our validation plan and our relocation plan from a technical point of view, and discuss our various procedures for measurement and range validation. The philosophy and methodology of the proposed site selection and measurement for the validation of the Tucson test facility will also be presented. This paper will also present the resolution of encountered risks and problems.

BICOMS Antenna Positioner System (APS) and Automated Field Probe (AFP)
O.D. Asbell,M. Hudgens, November 1998

BICOMS (Bistatic Coherent Measurement System) is a RATSCAT radar cross section (RCS) range at Holloman AFB, NM. BICOMS includes a Mobile Radar Unit (MRU), Fixed Radar Unit (FRU), and an Automated Field Probe (AFP). The MRU's antenna positioner system moves eight antennas using single pivot elevation/azimuth positioners and screw jack and cable hoist height actuators. The Automated Field Probe (AFP) raster scans a 40 x 40-foot aperture in front of the target under test. A 4- wheel drive scissors lift provides mobility and vertical axis travel. A cable drive moves a carriage horizontally along a 48-foot truss boom, mounted on the lift platform. The system computer controls both axes, as well as microwave data acquisition. All structures and systems feature minimum weight and wind resistance.

High Precision Dual Test Mode-Based Antenna Measurement Facility, A
J.F. Aubin,D.R. Frey, J. Caserta, W. Kohler, November 1998

ORBIT/FR has recently designed an antenna measurement facility that combines a unique encoder­ based positioning system with the ability to test antenna systems in both transmitting and receiving modes of operation. This combination allows for the testing of high precision military, space borne, and commercial antennas and systems in their final, deliverable configuration. The system features a high precision roll over slide over azimuth positioning system, with angular precision of 0.001-0.002 degrees available. In addition, accurately located roll axes can be interchanged to accommodate various size classes of antennas. As part of the positioning system design, an extremely low profile AL- 060 roll axis provides for non-intrusive positioning of very small antennas. Automatic mode switching allows the antenna under test to be tested in either a transmit or receive mode of operation without operator intervention required. The system features the FR959 Automated Antenna Measurement Workstation and HP 8530 based RF instrumentation for data acquisition and control. The system is designed for operation over a frequency range of 800 MHz to 40 GHz. Band switching also allows for contiguous operation of the instrumentation, limited only by the available probe antennas utilized with the system.

Development of Standardized Procedures for Antenna Measurement Ranges
J.W. Moffat,C.B. Brochu, G.A. Morin, M.E. Kelly, November 1998

The DREO-DFL Antenna Research Lab (DDARLing), contains far-field and planar near-field antenna measurement ranges. Measurements can be made on both ranges from 1.0 to 62.5 GHz. In the early implementation stages of our antenna measurement ranges, most of our energy was absorbed in mastering the mechanics of the positioners and the intracies of the operation of the software, and addressing component failures. To make useful measurements, it is necessary to minimize system errors. Early experience and frustration has led us to the development of an ordered series of standardized procedures that are aimed at careful set-up, calibration, and operation of the ranges. Within these procedures, attention is paid to the identification and minimization of errors due to alignment, equipment calibration, linearity, leakage, multipath, and drift. Following a brief description of the two ranges in the DDARLing facility, the paper provides details of one of these procedures.

Millimetre-wave antenna testing for production
D.A. McNamara,D.J. Janse van Rensburg, P. Cowles, November 1997

Concurrent engineering concepts that have been in use in other industries for many years can be used successfully in millimetre-wave antenna production for space applications. This paper demonstrates the key role played by the proper consideration of RF testing as part of this overall production process.

Measurement considerations for antenna pattern accuracy
J. Swanstrom, November 1997

This paper examines antenna measurement errors attributable to instrumentation, and their effect on measurement uncertainty.

G/T measurement of small antennas
R.B. Dybdal, November 1997

The G/T measurement of large antennas using radio source techniques is well established. What is less well known is that this technique is also useful in characterizing relatively small antennas . The application of radio source techniques to smaller antennas is discussed. An estimate of the minimum size antenna that can be measured by this technique is provided. The measurement technique is reviewed along with techniques to measure the total system temperature, which is required when the antenna gain must be established.

Radio frequency (RF) visual detection concept
A., Dr. Torres, November 1997

A unique and novel concept is presented for the visualization of Radio Frequencies. The concept will allow the visualization of radio waves, independent of frequency, which can not only provide detection of their presence but which can also describe their spatial properties, e.g. intensity distributions and footprints.

Errors analysis of near-field measurement
G. Seguin,T. Pellerin, November 1997

The objective of this study is to evaluate the measurement errors of a near-field range at in order to develop some techniques to minimize them. Measurements were performed on a standard gain horn as references. The methodology presented demonstrates that it is feasible to calculate the far-field radiation from near-field measurement with one deconvolution that will include all the errors introduced by the instrumentation

119 GHz CATR based on a 2.4 m hologram
T. A. Hirvonen,A. Raisanen, J. Ala-Laurinaho, J. Tuovinen, P. Piironen, November 1997

A development work of a 2.4 m x 2.0 m hologram for testing the 1.1 m offset reflector of the Odin satellite at 119 GHz is reported. The analysis of the hologram is based on physical optics (PO) and finite difference time domain method (FDTD). The hologram is fabricated with an etching process. A comparison between the theoretical and measured quiet-zone fields of the hologram type of compact antenna test range (CATR) is made.

Intelligent cruise control radar development
E. Walton,D. Farkas, F. Paynter, November 1997

As part of the 1997 Automated Highway System Demonstration, the Ohio State University ElectroScience Laboratory (OSU/ESL) developed and operated a pair of automobiles equipped with radar systems for steering and cruise control. In a national demonstration attended by six autonomous vehicle teams, the system was used to convoy three autonomous vehicles along a 7 mile stretch of closed highway lanes near San Diego. The goal of the look ahead radar system was to acquire and track the vehicle ahead.

Phase-retrieval using non redundant sampling representations
O.M. Bucci,G. D'Elia, M.D. Migliore, November 1997

A general approach for phase-retrieval is discussed. The representation is based on an advanced non-redundant sampling representation and is able to explicitly take into account geometrical characteristics of the source, like the overall dimension and the general shape, as well as a priori inforn1ation on the near-field and far-field.

Radar image normalization and interpretation
J.P. Skinner,B. Kent, D. Andersh, D. Mensa, R.C. Wittmann, November 1997

Calibrated radar images are often quantified as radar cross section (RCS). This interpretation, which is not strictly correct, can lead to misunderstanding of test target scattering properties. To avoid confusion, we recommend that a term such as "scattering brightness" (defined below) be adopted as a standard label for image-domain data.

NetCDF - a file format suitable for antenna measurements
M. Dich,J. Karlsson, P. Malmborg, November 1997

Transferring data from a measurement facility to other internal or external users of the data are often troublesome. In this paper we present a data file format which is independent of platform, operating system and programming. Thus it is very suitable for simplified exchange of data. The format is described and a simple example is given how to read and write data in a file. With this paper we would like to promote further development and use of this format in the antenna measurement society.

Squat cylinder and modified bicone primary static RCS range calibration standards, The
B. Kent,W.D., Jr. Wood, November 1997

This paper describes the current status of the present cylinder family, and introduces theoretical and experimental RCS data for a modified "bicone" calibration standard. These standards, when used appropriately, greatly improve the quality and efficiency of primary RCS calibration measured within indoor or outdoor ranges. These techniques should offer range owners fairly simple methods to monitor the quality of their primary calibration standards at all times.

Rocket motor plume measurement facility
W.W. Harrington, November 1997

The Plume Measurement Facility is a new outdoor facility providing the capability to characterize tactical rocket motor plumes. Radar cross section of the plume is measured by both a near field and a far field radar. Infrared/ultraviolet/visible (IR/UVNIS) charac­ teristics are measured by numerous instruments recording spacial, temporal, and spectral data. All instrumentation is calibrated and adjusted to realtime standard day meteorological data and all data is recorded on a common synchronized time base.







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