Electromagnetic Compatibility Antenna Research Articles

Implementation Possibilities of Standard Site Method Sub-cases for EMC Antenna Calibrations in Non-ideal Site Conditions

Today, a number of engineering issues require electromagnetic compatibility (EMC) tests, in turn triggering the need for EMC-antenna calibrations. In this framework, experimenters seek accurate and time-saving solutions. Basically, standard site method (SSM) ANSI C63.5-2006 stipulates the near-to-ideal conditions on an empty and vast land, where three antennas are used for antenna factor determination. In our previous work, we investigated the suitability of narrow test sites for antenna calibration according to three-antenna SSM-ANSIC-63.5-2006, whose usability was validated under certain conditions. In the present study, we expand our research by applying the sub-cases of using a known antenna and identical antennas specified in the standard in order to shorten the calibration process. The results reveal that the methods for various calibrations are useful for successfully running the process even in non-ideal sites and help significantly reduce the experimentation time, considering the uncertainty limits specified in EMC test standards.

Design a Compact Printed Log-Periodic Biconical Dipole Array Antenna for EMC Measurements

This article presents the design, modeling, and fabrication of a printed log-periodic biconical dipole array antenna (PLPBDA) for electromagnetic compatibility (EMC) measurements. The proposed structure used bow tie-shaped dipoles instead of typical dipoles to achieve a size reduction of 50% and bandwidth enhancement of 170% with the help of PCB technology. Furthermore, the balanced feeding method and the modifications in bow tie-shaped dipole dimensions were utilized to obtain broad bandwidth of 5.5 GHz (from 0.5 GHz to 6 GHz). This structure comprises 12 dipole elements with a compact size of 170 × 160 × 1.6 mm, reflecting low fluctuations gain of about (4.6–7) dBi with the help of an extra dipole. Moreover, the achieved frequency and radiation characteristics (simulated and measured) agree with each other and are compatible with the results of classical EMC antennas. The achievements of this structure showed promising results compared to both literature reviews and reference antenna Hyper LOG® 7060 offered for sale.

Search for suitability of relatively narrow test sites for antenna calibration according to ANSI C63.5-2006 standard site method – A case study in Istanbul-Turkey

In today’s world, electromagnetic compatibility (EMC) tests are of primary significance, increasing the importance of accurate measuring of EMC antenna factors. The standards for antenna calibrations require near-ideal conditions as empty space above ground plane with very large dimensions. We investigate the possibility to use the open-area test site (OATS) of Turkish Standard Institution (TSE) for antenna calibrations, which is generally used for EMC product tests. Although the physical dimensions of the site are limited and the dominating component in the overall uncertainty is the one due to site conditions, the measurements and the uncertainty budget put forth that the site can be used for calibrations according to ANSI-C63.5-2006. We hope this study will be significant in directing experimenters to consider the aspect that one should not expect near-ideal conditions to start the calibration process. In this context, a detailed uncertainty analysis is performed together with a site validation process.

An Improved Method for Free-Space Antenna-Factor Measurement by Using the MUSIC Algorithm

This paper proposes a simple, fast, and accurate method for calibrating the free-space antenna factors of broadband electromagnetic compatibility (EMC) antennas. This method adopts a fixed-height calibration configuration and a multiple-signal-classification-based (MUSIC) data processing algorithm. Because this configuration does not require height scans, it significantly shortens measurement time and removes height-dependent calibration errors. In addition, the MUSIC-based data processing algorithm can remove unexpected reflections from the ground plane or any other reflecting objects, and transfer calibration into the free-space transmission model, from which the free-space antenna factors are obtained. The algorithm of this method can also automatically compensate for the phase center shift, which makes measurement easier and more convenient. To verify this method, numerical simulations for half-wave dipoles and experimental measurements for log-periodic dipole array (LPDA) and horn antennas are conducted. The simulated results for the half-wave dipoles indicate that the error from the theoretical AF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FS</sub> can be within ±0.5 dB. In the case of the experimental measurements, the calibrated results are compared with other published standard methods: the mean differences can be as low as 0.25 dB for the LPDA, and as low as 0.36 dB for the horn antennas. The good agreement between results confirms that the proposed method can yield accurate estimations of free-space antenna factors for broadband EMC antennas. This method also provides a new alternative for obtaining fast and accurate antenna calibration.

The accurate calibration of EMC antennas in compact chambers — Measurements and uncertainty evaluations

The accurate knowledge of the antenna factor is a fundamental requirement for reliable electromagnetic compatibility (EMC) measurements in emissions, immunity and human exposure tests. According to international standards, the calibration of EMC antennas requires close-to-ideal test sites (or calibration test sites), characterized by very large sizes of the ground plane and of the empty space volume above it (free-space behaviour). On the other hand a great number of EMC test sites are available and designed for measurements at 3 m distance, therefore it would be very convenient to calibrate antennas in such facilities at the cost of an acceptable loss of accuracy. In this paper, the authors investigate the suitability of compact semi-anechoic chambers (standard chambers, compliant for measurements at 3 m distance from the equipment under test) for reliable antenna factor calibrations. As an application, the calibration of a common broadband biconical antenna in the 200–1000 MHz frequency range is here considered and analysed. A detailed experimental analysis is offered for estimating all the relevant uncertainty contributions.

The Antenna as a Transducer: Simple Circuit and Electromagnetic Models

Antennas are key elements in electrical engineering. They are the first and most essential parts of a communication/radar system, and basic instruments for electromagnetic compatibility (EMC) tests and measurements. A good design for a transmitting or receiving antenna system or array may reduce the installation and operating costs more than 30-50%. Moreover (up to a certain extent), noise and interference may be eliminated at the front end of the receivers. A communication or radar antenna system basically covers narrow operating bands and operates in the far field. On the other hand, EMC antennas operate over broad bands and use near fields. This tutorial aims to discuss some aspects of these very well-known devices that are often neglected or forgotten, because of their simplicity.