Basic Rules for Anechoic Chamber Design, Part One: RF Absorber Approximations

Author: Vince Rodriguez

Publication: Microwave Journal Magazine, January 2016

Copyright Owner: Microwave Journal

The task of adequately specifying performance for an indoor anechoic chamber without driving unnecessary costs or specifying contradictory requirements calls for insight that is not always available to the author of the specification. While there are some articles and books13 that address anechoic chamber design, a concise compendium of reference information and rules of thumb on the subject would be useful. This article intends to be a helpful tool in that regard. It starts by recommending the proper type of range for different antenna types and frequencies of operation. Rules of thumb are provided to select the best approach for the required test or antenna type. The article concentrates on rectangular chambers. Simple approximations are used for absorber performance to generate a series of charts that can be used as a guide to specify performance and appropriate facility size.

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Telematic Antenna Testing

Authors: Dr. Donald G. Bodnar, Dr. Daniel N. Aloi

Publication: Electronic Component News Magazine (ECN) 2010

Cypyright Owner: Advantage Business Marketing

Today’s automobiles have a wide variety of RF systems with antennas on them for Sirius and XM radio, collision avoidance radars, the Global Positioning System (GPS) and other systems. Conventional test facilities can only perform terrestrial directed pattern measurements of the antenna on the automobile. Special test facilities are required when the automobile must communicate with a satellite as well as other ground systems. Table 1 provides a partial list of satellite-based wireless systems below 2.5 GHz in frequency. This paper discusses a system specially designed for making antenna measurements from the zenith to the horizon. In addition, some of the issues involved in making satellite band measurements such as Sirius/XM and GPS and terrestrial band measurements such as CELL800 and CELL1800 are reviewed.

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The IsoFilter^TM Technique: A Method of Isolating the Pattern of an Individual Radiator from Data Measured in a Contaminated Environment

Author: Doren W. Hess

Publication: IEEE Antennas and Propagation Magazine (Volume: 52 , Issue: 1 , Feb. 2010)

Copyright Owner: IEEE

This paper describes a novel method, termed the Isofilter^TM Technique, of isolating in the measured data the radiation pattern of an individual radiator from among a composite set of radiators that form a complex radiation distribution. This technique proceeds via three successive steps: A spherical NFFF transform on an oversampled data set, followed by a change of coordinate system followed in turn by filtering in the domain of the spherical modes to isolate a radiating source. The end result is to yield an approximate pattern of the individual radiator largely uncontaminated by the other competing sources of radiation. I.

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Military Radome Performance and Verification Testing

Author: Thomas B. Darling

Publication: (MPD) Microwave Product Digest

Copyright Owner: NSI-MI Technologies

Incredible efforts are made by system designers to produce state-of-the-art radar and other RF based capabilities for our military. Modern radar systems are used for various purposes including, but not limited to: weather assessment; navigation; terrain following/terrain avoidance; weapons fire control; electronic warfare; enemy tracking, listening and identification, etc.

Dependant upon extremely high measurement precision, repeatability and accuracy, these radar systems all require protection from the elements. While many think about the exotic hardware and sexy looking screen shots produced by these sophisticated radar systems, most do not think about one extremely critical component of these systems: the radar dome or radome. When one considers the critical need for proper operation of these systems for our military, as well as the harsh conditions during conflicts, this component protects vital systems which can make the difference between survival and disaster.

The most well recognized radome is the one positioned on the nose of an aircraft or missile. However, many military applications, and new commercial applications, are positioning microwave based systems in other locations on the aircraft. These often require odd shapes in order to protect the RF system and to be sufficiently aerodynamic. Military radome testing is, not surprisingly, considerably more involved than for commercial applications.

RCS Measurements in a Compact Range

Authors: Jeff Fordham, Marion Baggett

Publication: (MPD) Microwave Product Digest

Copyright Owner: NSI-MI Technologies

The Radar Cross Section (RCS) of an object is defined as, “the area intercepting that amount of power which, when scattered isotropically, produces a return at the radar equal to that from the target.” In simpler terms, RCS is the projected area of a sphere that has the same radar return as the target. The unit of measure for an object’s RCS is “decibels per square meter,” or dBsm. The power received by a radar for a target indicates how well the radar can detect or track that target. For this reason, much research and effort has been put into reducing the “signature” of various aircraft, ships and other objects.

Wireless Antenna Measurements

Author: Dr. Donald G. Bodnar

Publication: (MPD) Microwave Product Digest

Copyright Owner: NSI-MI Technologies

We are witnessing an explosive expansion of RF transmitting and receiving products due to consumer demand for wireless voice and data connectivity and the availability of cost-effective technology to produce such products and services. Developers of these new products are keenly interested in the pattern, gain and polarization of their products. Traditional antenna measurement equipment can provide the needed information but usually at a prohibitively high price since such test equipment was designed for general purpose, very high precision aerospace applications. Many of the features needed in aerospace antenna measurements are not required in wireless applications. For example, aerospace measurements are often made at 35 or 95 GHz while wireless communication devices often work at 800 or 1,900 MHz. In addition, phase and amplitude measurements are made in the aerospace applications while wireless measurements usually only require amplitude information.