Spherical Near-field Test Research Articles

Antenna Performance Test Method and Result Analysis for V2X Communication of Connected Vehicle

This paper proposes an antenna performance test method for vehicle-level to ensure the stable communication capability for vehicular networking technology and application. Firstly, considering the large size and heavy weight of characteristic for the vehicle, a spherical near-field test for the vehicle antenna test is then proposed in the paper. Secondly, the impact of the vehicle body on the antenna performance is analysed by comparing the different performance between different vertical angles and antennas. Finally, the experimental results verify the validity and correctness of this method.

Customized Spherical Near-Field Test Time Reduction for Wireless Base Station Antennas

Effective spherical near-field (SNF) test time reduction approaches are presented for wireless base station antennas that have widely differing beamwidths in the azimuth and elevation planes. The geometry of these antennas allows for the optimization of the SNF angular sampling density by allowing a lower sampling density along one of the acquisition axes. This is validated experimentally and shown to reduce the SNF test time significantly without degrading the measurement accuracy.

Single-Negative, Double-Negative, and Low-index Metamaterials and their Electromagnetic Applications

Spherical near-field measurements have become a common way to assess the performance of a wide variety of antennas. However, published reports on range-error assessments for spherical near-field ranges are not very common. This is likely due to the perceived additional complexity of the spherical near-field measurement process, as compared to planar or cylindrical measurement techniques. This paper will establish and demonstrate a simple procedure for characterizing the performance of a spherical near-field range. The measurement steps and reporting can be largely automated with careful attention to the test process. We will summarize the process and document the accuracy of a spherical near-field test range at nearfield systems (NSI), using the same NIST 18 terms commonly used for planar near-field measurements

AMTA Coner

Spherical near-field measurements have become a common way to assess performance of a wide variety of antennas. Published reports on range error assessments for spherical near-field ranges however are not very common. This is likely due to the perceived additional complexity of the spherical near-field measurement process as compared to planar or cylindrical measurement techniques. This paper will establish and demonstrate a simple procedure for characterizing the performance of a spherical near-field range. The measurement steps and reporting can be largely automated with careful attention to the test process. We will summarize the process and document the accuracy of a spherical near-field test range at NSI using the same NIST 18 terms commonly used for planar near-field measurements.

A novel lightweight dual-frequency dual-polarized sixteen-element stacked patch microstrip array antenna for soil-moisture and sea-surface-salinity missions

The main motivation for this paper is to discuss the development of a novel compact and light-weight dual-frequency, dual linearly polarized, high-efficiency, stacked-patch microstrip-array antenna for use in standalone aircraft-based remote sensing applications. Results from simulation, fabrication, and testing of a sixteen-element stacked-patch array antenna, optimized for an L-band frequency of operation, are presented. The design center frequencies were 1.26 GHz and 1.413 GHz with 10 MHz and 25 MHz bandwidths in each band, respectively. Due to the large number of design parameters and demanding design requirements of beam-efficiency, sidelobe levels, and polarization characteristics, particle-swarm optimization (PSO) and finite-difference time-domain (FDTD) simulations were used for synthesis and analysis. Cancellation techniques, based on symmetry, were applied to the antenna ports, with a custom-built feed network to reduce cross polarization. Simulations and measurement results from a spherical near-field test facility confirmed excellent performance of the array configuration, with a beam efficiency of greater than 90%, isolation better than -35 dB, and cross polarization in the main beam of the array better than -40 dB. From the sixteen-element array simulations and experimental verifications, one of the objectives of the present study is to suggest the possibility of using customized dual-frequency, dual-polarized arrays as potential feeds for reflectors to replace the traditionally used conical horns for future soil-moisture and sea-salinity missions

Spherical near-field scanning at the Technical University of Denmark

The early work (1969-79) on spherical near-field antenna measurements at the Technical University of Denmark (TUD) is outlined. A spherical near-field transmission formula is described and the first probe-corrected spherical near-field measurements are discussed. The TUD-ESA (European Space Agency) joint effort on spherical near-field testing is also described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Comparison of near-field range results

Comparisons of measurements on a contoured beam antenna carried out at five independent European test ranges are presented. They include a compact antenna test range, two cylindrical near-field test ranges, and two spherical near-field test ranges. The comparisons illustrate problems in the determination of gain values and cross polarization, while the agreement in the copolar patterns and the peak directivity is very good.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Experimental evaluation of the spherical near field test range

In aircraft manufacturer firms there is the need for measuring antenna patterns of large beamwidth communication/navigation antennas with the scale modeling technique. A series of tests has been carried out to verify the use of the spherical near field (SNF) test range for this purpose. The comparison is made between measured and calculated data of stub and waveguide antennas installed on a cylinder. From the results it appears that the agreement is reasonable. The advantages and disadvantages of the SNF test range for this particular application are discussed.