Anechoic ranges require constant temperature and humidity control, proper lighting for safe work inside the chamber, and closed-circuit television (CCTV) cameras to monitor the system during measurements. In addition, anechoic chambers require fire detection and suppression systems. Traditionally, such penetrations are minimized and placed in non-critical areas, with the assumption that their effects would be negligible if located away from sensitive regions. However, the true impact has not been fully investigated.
In this study, antenna measurements are simulated in an indoor far-field range. A range antenna (or near-field probe) and an antenna under test (AUT) are placed in free space, and the AUT is rotated at discrete angles. A second model then introduces CCTV cameras, HVAC vents, light fixtures, air sampling tubes, and fire suppression nozzles positioned around the chamber. The simulation with these added features is repeated at the same discrete angles.
The model assumes a perfect absorber and does not account for the potential shadowing effects of pyramidal absorbers. While approximate, the results provide a worst-case estimate of the measurement error introduced by necessary chamber penetrations. These results can be used to assess potential uncertainties in measurements caused by support systems within the anechoic enclosure. The technique is demonstrated for indoor far-field ranges but can also be applied to near-field and compact ranges. Results show that, for a typical roll-over-azimuth positioner, the effects of ceiling penetrations are minimal, with differences in the -35 to -40 dB range.

Space exploration captivates us because it speaks to one of humanity’s deepest instincts—the desire to understand our origins and our place in the cosmos. By venturing beyond Earth, we not only uncover the mysteries of distant planets, stars, and galaxies but also gain profound insights into our own world. From searching for signs of life on other planets to studying the birth of stars and the evolution of galaxies, each discovery reshapes our understanding  of the universe and ourselves. Space exploration challenges us to innovate, to collaborate across borders, and to dream beyond what we think is possible. Ultimately, it reminds us that while we are a tiny part of the universe, we are also a curious and resilient species capable of reaching for the stars.
Space exploration is driven by fundamental scientific questions and the pursuit of innovative instruments to answer them. Our work focuses on designing and building advanced instruments that enable precise measurements to support these scientific investigations. In this presentation, we will provide an overview of the state-of-the-art instruments currently under development and highlight the key science questions they are designed to address. Rapid advancements in areas such as commercial modeling software, low-loss circuit and interconnect technologies, mobile device innovations, and submicron scale lithography are now making it possible to develop smart, low-power, and highly capable instruments—many of which are compact enough to be deployed on Small Sat or CubeSat platforms. We will also explore the challenges and opportunities associated with next-generation instruments and their role in meeting the demands of future scientific missions.

Industrial robots offer significant potential for advancing antenna measurement methodologies, due to their high flexibility, precision, and reliability. Their ability to follow complex trajectories and accommodate unconventional test setups enables innovative approaches for both production testing and the development of multifunctional measurement facilities, especially in spatially constrained scenarios. Although the use of robotics in antenna measurements is still relatively new, the increasing maturity of robotic antenna measurement systems is driving their adoption in both industrial and academic settings. These systems are being applied not only to standard pattern measurements but also to more advanced and customized testing scenarios. In particular, robotic systems show great potential in spherical near-field (SNF) antenna measurements. The flexibility in defining arbitrary sampling grids allows for the application of irregular sampling schemes and compressed sensing (CS) techniques. These approaches can substantially reduce the number of required measurement points, thereby decreasing the overall measurement time, an improvement that is often not feasible with conventional mechanical positioning systems. Despite these benefits, unlocking the full potential of robot-based antenna measurement systems involves overcoming several technical challenges like ensuring precise alignment, optimizing trajectory planning algorithms, and integrating radio frequency (RF) subsystems with robotic motion control. This talk presents current developments in robotic antenna measurements and showcases practical implementations using the robot-based millimeter-wave test facility at the Institute of High Frequency Technology, RWTH Aachen University.

In the near future, high-speed wireless networks will leverage the abundant bandwidth available in the sub- and millimeter frequency ranges, mainly through XG systems and New Space technologies. Innovations in antenna technology are essential to fully exploit these wide bandwidths and provide efficient data links for mobile users. Long slot arrays present a very attractive solution, offering decade-wide bandwidths, a very large field of view, and a low-profile design. During this presentation, I will discuss the modeling of long slot arrays and highlight their advantages in terms of bandwidth and scanning capabilities, as well as their physical implementation. We will explore how quasi-optical planar systems can be used to feed these arrays, functioning as efficient beamformers for multi-beam, wide-scanning antennas. Quasi-optical systems help to minimize the losses and costs associated with beamforming networks for arrays operating at higher frequencies while maintaining the flexibility of the radiating unit. I will also cover the implementation of long slot arrays across various technologies, particularly in millimeter and sub-millimeter frequency bands, aimed at next-generation terrestrial and non-terrestrial networks. Finally, I will showcase the capability of these arrays to radiate short, high-power pulses, extending their applications into high-power scenarios.

Measurements of spatially distributed fields require a relative motion between the field source and the sampling probe to reach the designated sampling points distributed over the spatial extent of the field. For stop-go sampling, where the motion is stopped at the sampling points while the data acquisition system samples the probe signal, the measurement time can become unacceptably long due to the mechanical deacceleration, fine-positioning, and acceleration of the positioning system at each sampling point. For on-the-fly sampling, where the motion is continuous and the data acquisition system is triggered-by-position as the sampling points are reached, the measurement time can be significantly shorter. Since all measurements are affected by random measurement noise, the sample of the probe signal at the individual sampling point is almost always formed by combining multiple individual A/D conversions in the measurement receiver. Here, we refer to this as signal averaging; it is well known that by averaging N independent A/D conversions, the signal-to-noise power ratio increases by a factor N; e.g. averaging 1000 A/D conversions increases the signal-to-noise ratio by 30 dB. With go-stop sampling, all A/D conversions are made at the same spatial point, the sampling point, and thus for the same field; this corresponds to coherent sampling. However, for on-the-fly sampling, the A/D conversions are – due to the continuing relative motion between source and probe – made at slightly different spatial points and thus for slightly different fields; this corresponds to incoherent sampling and it results in smearing of the probe signal. For increasing number of averaged A/D conversions or for increasing speed of the positioner, the resulting smearing error may become unacceptably large. This presentation will demonstrate how the smearing error due to signal averaging for on-the-fly sampling can be exactly quantified and also exactly corrected – for both non-periodic and periodic bandlimited signals.

In recent times, we have become familiar with the use of commercial software for designing our antennas and microwave devices. This is very common since it is easy to find high-performance desktop computers at affordable prices in our daily lives. The use of general-purpose commercial software is widespread because it allows for the simulation of any arbitrary configuration. However, many of us have experienced, given the ease of using commercial software, trying to simulate electrically large electromagnetic devices which take days or, in some cases, cannot be completed at all. While it is true that we now have very powerful simulation tools, by making a few simple assumptions, we can significantly reduce computational time without sacrificing accuracy.
In this talk, I will introduce a simple ray-tracing technique that can be used, in combination with physical optics, to calculate the radiation pattern of antennas, as well as directivity, gain, mutual coupling, and even early-time response in complex configurations. The results are not only faster than those produced by conventional commercial software, but also more accurate, as they avoid many of the numerical errors that typically arise when computing electrically large structures.

Reconfigurable intelligent surfaces (RISs) – or programmable metasurfaces- have recently attracted the attention of several diverse research communities, mostly for applications related to wireless communications and sensing. RISs are relatively low-cost structures that are scalable to large apertures and provide electronic beam reconfiguration (focusing, beamscanning, etc.). As such, RISs exhibit many attributes that could be used to simplify the antenna measurements. By leveraging its ability to steer reflections dynamically in both azimuth and elevation planes, the RIS can act as a programmable probe to illuminate the antenna under test (AUT) from multiple incident angles without requiring mechanical movement. In this way, the RIS can generate a diverse set of measurement bases that, when combined with near-field scanning or a compact sensor array, enable efficient reconstruction of the AUT’s far-field radiation pattern. Compared to conventional mechanical goniometers or large anechoic chambers, this approach provides a more compact and reconfigurable testbed.
Our group has designed and prototyped several RISs in the microwave and millimeter wave bands. In a recent work, we devised a mmWave (28 GHz) RIS that offers electronically controllable high-resolution beam steering with strong suppression of quantization lobes. The scalability of our tiled RIS architecture provides flexibility for measurement setups. Larger apertures can generate narrower beams with finer angular selectivity, which is advantageous for high-directivity antenna characterization. At the same time, the low-cost PCB-compatible fabrication of RIS allows deployment in practical over-the-air (OTA) test environments for 5G/6G antennas, user equipment, or phased arrays. Furthermore, the pseudo-random pre-coding of the RIS suppresses spurious lobes that could otherwise corrupt measurements, ensuring that only the desired beam is used to interrogate the AUT. This feature enhances measurement accuracy and reduces ambiguities in pattern reconstruction—an advantage over traditional binary RISs.
During the conference, we will present the design of the scalable mmWave RIS and discuss the measured radiation and beam shaping properties. Then, we will present various approaches in using the RIS as a component of a measurement system to characterize directive mmWave antennas.