A Low Cost Portable Near-Field Antenna Measurement System

Author: Dan Slater, Greg Hindman

Publication: AMTA 1989

Copyright Owner: NSI-MI Technologies

Implementing an antenna test range has traditionally been viewed as a major and costly undertaking, requiring significant long term facility planning, computer hardware interfacing, and software development. This paper describes a complete low cost, yet high accuracy portable near-field measurement system that was privately built for less than $2,000 and interfaced to a PC compatible computer.

The design and operation of this system, including the scanner, microwave hardware, and computer system will be described. This system has since been extended into a commercial product capable of providing rapid and accurate measurements of small to medium size feeds and antennas within a small office or lab space at significantly lower cost than standard antenna test techniques. The system has demonstrated an equivalent sidelobe noise level of less than -50dB, includes a probe corrected far-field transform and holographic back projections, and can output pattern cuts, contour plots, 3D plots, and grey scale images of antenna performance.

Error Suppression Techniques for Near-Field Antenna Measurements

Author: Dan Slater, Greg Hindman

Publication: AMTA 1989

Copyright Owner: NSI-MI Technologies

This paper describes techniques for coherently suppressing multipath and other error sources in planar near-field measurements. Of special interest is a simple, yet effective technique for suppressing axial multipath and mutual coupling between the near-field probe and an antenna. This is of particular value in the testing of low sidelobe antennas. Traditionally, self comparison tests with different separations between the probe and the antenna under test are used to identify the magnitude of multipath errors. What is not generally realized is that these tests can be used to produce a coherent estimate of the induced error, which can often be suppressed. A series of tests was performed with a small X-band phased array antenna, resulting in a reduction of the sidelobe noise background from a 25dB level to better than 50dB.

Guided Weapons Radar Testing

Author: Richard H. Bryan

Publication: AMTA 1989

Copyright Owner: NSI-MI Technologies

An overview of non-destructive real-time testing of missiles is discussed in this paper. This testing has become known as hardware-in-the-loop (HIL) simulation because it involves the actual missile hardware.

Hand Held Microwave Reflectometer

Authors: Dan Slater, Greg Hindman

Publication: AMTA 1989

Copyright Owner: NSI-MI Technologies

Measurements of the microwave reflectivity of materials is often performed with complex test setups using probes attached to a vector network analyzer. The lack of portability of these systems prevents the user from measuring reflective properties of surfaces that are not easily moved to an appropriate test facility. This paper describes a small, hand held microwave reflectometer which is designed to perform rapid reflectivity measurements in the field. The reflectometer consists of a tuneable Ku band source, a dual polarization sampling horn, a pair of crystal detectors, and a battery powered microcomputer.

High Speed, Multi Frequency Measurements

Authors: 0. M. Caldwell

Publication: AMTA 1989

Copyright Owner: NSI-MI Technologies

Precise and complete measurements of advanced electromagnetic systems demand dramatically higher data acquisition speeds than those commonly attainable. Specific challenges include requirements for wideband measurements with arbitrarily spaced frequency steps. These types of measurements are often encountered in characterizing EW/ECM systems, radars, communications systems, and in performing antenna and RCS measurements.

The MI Technologies Model 1795 Microwave Receiver offers capabilities directly applicable to solving measurement problems posed by highly frequency agile systems. These problems include: <0l>

A technique is discussed which shows the application of the Model 1795 Microwave Receiver in its high frequency agility mode of operation. Measurement examples are presented showing the advantages gained compared to previous methods and instrumentation configurations.

Improving Antenna Test Range Productivity

Authors: James D. Huff

Publication: AMTA 1989

Copyright Owner: NSI-MI Technologies

This paper presents the productivity improvements that are possible in complex antenna measurements using state of the art instrumentation. The productivity improvement is calculated for a hypothetical antenna, and from this productivity improvement manufacturing cost reductions and payback times are derived.