Download Free An Investigation Of Adaptive Acquisition Techniques For Planar Near Field Antenna Measurements Book in PDF and EPUB Free Download. You can read online An Investigation Of Adaptive Acquisition Techniques For Planar Near Field Antenna Measurements and write the review.

This thesis presents a practical approach to reduce the overall testing time in a spherical near-field (SNF) antenna measurement environment. The premise of this work is that the acquisition time is mostly dominated by the mechanical movement and the processing electronic. Moreover, it is assumed that the transformation time to go from the near-field domain to the far-field domain (NF-FF transform) is small compared to the acquisition time. Thus this operation can be done repeatedly while the acquisition is on-going without significantly affecting the overall test time. This situation allows to continuously evaluate the far-field (FF) of the antenna under test (AUT), so that certain decision functions based on the radiation pattern of the antenna can be monitored. Such decision functions are based on the antenna specification, such as the gain, the side lobe level, etc. We do not proceed with a complete scan of the measurement sphere but effectively allow the probe to follow a directed path under control of an acquisition rule, so that the sampled near-field (NF) datapoints constitute an acquisition map on the sphere. The acquisition can then be terminated based on decision function values, allowing the smallest amount of data needed to ensure accurate determination of the AUT performance measures.
This single volume provides a comprehensive introduction and explanation of both the theory and practice of 'Planar Near-Field Antenna Measurement' from its basic postulates and assumptions, to the intricacies of its deployment in complex and demanding measurement scenarios. To do this the book initially examines the properties of antennas that allow them to enhance the free space interaction of electronic systems and this leads into a full description of the theory of 'Planar Near-Field Scanning'.
This book discusses the principles of forming and analysis of mathematical models of a wide class of antenna systems, new scientific directions in the development and application of computational algorithms for the study of mathematical models for antenna arrays of radio navigating systems. The book is presented for specialists in antenna system design; it may be useful for students of radio engineering specialties. This book consequentially uses the asymptotic correspondence of two-dimensional and three-dimensional problems to antenna engineering, that includes the influence of the placement objects for a given limited class of problems. Rigorous electrodynamics formulations of models and the use of efficient numerical methods provide the reliability and accuracy of modeling.
A scalar analysis was performed to determine the field structure in the focal region of apertures focused in their near field (f/D
This investigation is motivated by the difficulty of measuring certain multiple reflector antenna systems in a typical near field range configuration. The three primary objectives of this investigation are: (1) to investigate alternative planar near field measurement configurations, (2) to support computational simulation studies and (3) to investigate the performance of a particular dish plus splash plate antenna system.
The near-field measurement technique has been used extensively for electrically large antennas which can not be easily tested on a far-field range. In reconstructing the far-field antenna patterns from the near-field measurements, a planar configuration may be used with a computation based on the Fast Fourier Transform (FFT). The near-field data are generally sampled over a planar grid at the Nyquist sampling rate of (lambda sub zero)/2 spacing or less. For electrically large antennas, sampling at the Nyquist rate requires long data acquisition times over which significant system electronic drift may occur. Furthermore, the computer capacity may limit the largest size of the data set. Special data filtering techniques for large data sets have been reported. However, these techniques still require sampling at (lambda sub zero)/2 spacing.
This book summarises recent developments and enhancements in post-processing techniques that increase the quality and effectiveness of modern antenna measurements. Recent advances in near to far field transformation algorithms for enhancing measurement accuracy in the presence of different common error sources are explained in detail. Developments in techniques for reducing the effect of echoes, noise, and leakage, and to reduce acquisition time, are also explored. The book is written by a range of experts from academia and industry. It explains and illustrates by practical examples several very efficient source reconstruction techniques, and the use of modal and spatial filtering techniques to understand intimate features of measured antennas. It explains phase recovery techniques and demonstrates how combining simulations and measurements can allow for more accurate and faster antenna designs. The book is a useful resource for academics and industry professionals interested in both antenna measurement and design. ested in both antenna measurement and design.