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AMETEK is proud to exhibit at the DSEI conference in London, showcasing advance technologies that support global defense and security innovation. This year, multiple AMETEK business units are collaborating to present a unified front, highlighting integrated solutions across RF test and measurement, aerospace, and electronic instrumentation. Together, we demonstrate the power of partnership and innovation in delivering mission-critical capabilities to defense stakeholders worldwide. Delivering tomorrow’s technology today. DSEI website: www.dsei.co.uk Brochure

Authors: Mark. Ingerson, and Vince Rodriguez Publication: AMTA 2025 Copyright Owner: NSI-MI Technologies There are many antennas and microwave analysis and modeling software packages available, each with its preferred computational approach. Sometimes some of the available packages can use different numerical techniques. It is always gratifying if the solutions are consistent. Conventionally at NSI-MI compact range (CR) performance is evaluated with a proprietary software tool that drives two different approaches depending on the type of edge treatment. Serrated edge reflectors are handled using a well-known commercial package based on Asymptotic methods such as Geometrical (GO), Physical Optics (PO) and Geometrical Theory of Diffraction (GTD). For rolled blended-edge reflectors, the tool calls on a GO and modified unified theory of diffraction (UTD) introduced by Ellingson, Gupta and Burnside [1]. UTD used the method introduced by. Recently, NSI-MI has been using a commercial package based on the Method of Moments (MoM) using higher order basis functions. This tool showed correlation with the GO and m-UTD approach introduced in [1]. The results were presented in [2]. While the Asymptotic methods are faster and can be used for quick optimization of the design, they are not suited for analysis of the feed fence interaction, the reflector absorber skirt that hides the support structure or the interaction with the antenna under test (AUT) positioner. The MoM based approach allows for these types of analysis [3,4]. The MoM package leverages techniques like highorder basis functions (HOBFs), and sophisticated reduction methods. In this software a CR dish is modeled though the import of a CAD file that is used in the manufacture of the CR dish or is modeled within the software package GUI using its native CAD functionality. In this paper the quiet zone (QZ) performances predicted by the commercial package using asymptotic techniques and those predicted by the MoM-HOBF package are compared for a typical serrated CR dish. The QZ performance is determined by a set of metrics driven by amplitude and phase flatness along onedimensional cuts across two lateral and orthogonal axes centered at the center of the QZ as recommended in [5]. The results show that with the proper meshing constraints the performances modeled by the asymptotic approach and the MoM-HOBF are consistent and comparable for the cases presented in this. The long history of predictions that match the measured results upon implementation on the field of reflector designed by the asymptotic technique means that the MoM results can be used to accurately predict the performance of ranges while analyzing the effects of fences, skirts and the absorber on the AUT positioners that the MoM tool allows. View the paper

Authors: Vince Rodriguez, Mark Ingerson, Gwenael Dun, Esra Celenk Publication: AMTA 2025 Copyright Owner: NSI-MI Technologies The first mention of a Robot for near-field measurements of antennas appears is by Jeff Snow in [1]. This was a simple robotic arm to do planar measurements. About 7 years later, the use of off-the-shelf industrial robotic arms for doing antenna measurements is introduced [2]. Since then, industrialrobot- arm based antenna measurement systems have become increasingly popular due to their flexibility to measure over different surfaces allowing the system to do planar, spherical and cylindrical. The use of other methods to perform the transform, by numerically compute the currents on an arbitrary surface from the measured fields has helped in the growing popularity of robotic systems. This is related that the measurement surface does no longer have to be a canonical surface but can be any shape. However, the flexibility of the robots may be limited by the RF absorber coverage used in treating them. In this paper, the authors explore the potential scattering from the robotic arm in different positions and its effect on the probe illuminations. This is an area of research on the use of absorber that has not been explored until recently [3]. Numerical experiments are conducted to explore the effects of RF absorbers in the 300 MHz to 3 GHz range. Open ended waveguides (OEWG) as well as dual ridged horns (see Figure 1) are used as the probes. The results suggest that some areas of the arm need to be treated while others can be left bare. The analyses performed suggest that optimized treatment of robotic arms to maintain the flexibility of the technique while also reducing effects on the probe illuminations are possible. View the paper

Author: Scott T. McBride Publication: AMTA 2025 Copyright Owner: NSI-MI Technologies The approach of non-redundant near-field sampling has been available for many years. A general and automated approach that yields the expected time reduction for an arbitrary antenna volume, however, has been elusive. One of the more practical approaches is the “PNF wide-mesh” sampling, where the probe grid is separable in x and y, and this approach is the one explored in this paper. A fundamental step in non-redundant sampling is to identify a volume that fully contains the AUT. Constraints imposed by theory have typically led this volume to be rotationally symmetric about a z-oriented line, and often also require that the volume be more spherical (less oblate) than a volume circumscribing the AUT. That larger volume generally results in more acquisition time than would a conformal volume, but allows those samples to be readily interpolated to the conventional half-wavelength PNF grid. This paper examines the impacts of relaxing those constraints in order to further reduce the required sampling time for a box-shaped AUT. It then looks for ways to reduce or remove those impacts. The implementation of this algorithm involved a minor reformulation, specific to the PNF (or linear-axis) geometry, of the underlying non-redundant sampling theory. That reformulation is briefly described herein. A new family of tunable AUT-volume edge treatments similar to the existing “double-bowl” is also described. The paper will show minor reductions in predicted acquisition time compared to non-redundant sampling with a circular double-bowl volume. Each non-redundant approach typically offers a 40-60% reduction with a rectangular AUT volume compared to a full conventional scan. A more notable advantage of the new approach is a significant reduction in preacquisition activity defining the several parameters that govern the non-redundant acquisition and processing. View the paper