Microwave Vision Group (United States)

Plane Wave Generators (PWGs) utilize arrays of radiating elements to approximate plane wavefronts, thereby creating localized far-field-like conditions within a Quiet Zone (QZ). Their compact form factor makes them especially advantageous at low frequencies, such as in the VHF and UHF bands, where traditional Compact Antenna Test Ranges (CATRs) become impractically large. This paper presents results from a comprehensive validation campaign of a 19-element PWG demonstrator, conducted as part of a broader development program aimed at realizing a full-scale system for VHF/UHF testing. The campaign, executed at Pulsaart by AGC, involved both element-level and array-level assessments using a spherical near-field multi-probe system. Key objectives included validating QZ synthesis, calibrating array excitations via digital twin modeling and field expansion methods, and quantifying realized excitation errors. The findings confirm the robustness of the PWG design, the effectiveness of the calibration process, and the minimal impact of mutual coupling and active impedance variations on performance.

Current climate change is characterised by a growing number of extreme weather events and their impacts, which can have a significant impact on energy production, transmission and supply systems, with the potential for severe damage to assets and permanent or intermittent supply disruptions. In order to identify the likely regional climate impacts on specific elements of solar power generation systems, a complex analysis of the expected changes, the sensitivity of infrastructure and the possibilities to adapt to these changes is needed.Accordingly, one of the objectives of the research is to identify and characterize the climatological information and impacts that may pose a risk to solar energy generation facilities in the context of climate change. We investigate the role and significance of extreme weather events and their long-term projected changes for solar power systems in climate impact assessments. The changes of relevant meteorological events due to climate change and their impact on solar energy systems will be evaluated for Hungary based on data from regional climate model simulations available in EURO-CORDEX.

This document outlines the Over the Air (OTA) testing methodology which is currently employed for full automotive antennas and provides a pertinent Figure of Merit.

In a previous paper a new referenceless measurement set-up based on a reference antenna was used for characterizing the radiation of antennas in the planar scanner [1]. The method is based on using a low-cost receiver to retrieve the amplitude and phase of the signal. This paper explores the limitations of the method for different geometries and implements a multiprobe electromagnetic compatibility measurement system. Once the amplitude and phase are recovered, diagnostic techniques can be applied and also near-field to near or far-field transformations to calculate the field at distances defined by standards. The results demonstrate the good accuracy of the method in comparison with traditional electromagnetic compatibility laboratories.

Described here is a measuring system using a computer controlled network analyzer that allows observation of FM and TV broadcast antenna systems. Impedance measurement may be made at any point in a broadcast antenna system where access is possible. Most notably, the VSWR characteristics of an antenna on a tower may be measured from the ground without the effects of the transmission line. Measurement accuracy is 0.1 DB and 0.5 degree return loss with excellent repeatability. The system is suitable for field use allowing evaluation of the antenna and other parts of the RF system.