A Note to Show How an Alternative Spherical Mode Normalization Simplifies the Relationship Between Transmitting and Receiving Characteristics

Author: Doren W. Hess

In this paper we show how a modification in the choice of mode normalization changes the pair-wise transmitting-receiving conversion to a one-to-one equality for a reciprocal antenna... This change affords us greater simplicity and the opportunity to avoid confusion when manipulating the scattering coefficients. For this relation to hold, there is a useful convention defining two fiducial coordinate systems for the antenna – one a transmitting and the other a receiving coordinate system.

An Effective Strategy for Reducing the Truncation Error in the NF-FF Transformation with Helicoidal Scanning

Authors: F.D'Agostino, F. Ferrara, C. Gennarelli, R. Guerriero, G. Riccio, C. Rizzo

A sophisticated strategy for extrapolating the samples external to the measurement region in the helicoidal scanning is proposed in this paper. It relies on the nonredundant sampling representations of the electromagnetic field an on the optimal sampling interpolation expansions of central type. Such a technique uses the singular value decomposition method for evaluating the outside samples. The estimation of such data allow one to reduce the truncation error affecting the field interpolation in the zone close to the ends of the scanning cylinder, thus giving rise to a more accurate far-field reconstruction. Some numerical tests, assessing the accuracy fo the technique and its stability with respect to random errors affecting the data, are reported.

An Efficient Approach for Estimating the Data External to the Measurement Region in Helicoidal Scanning

Authors: F.D'Agostino, F. Ferrara, C. Gennarelli, R. Guerriero, G. Riccio, C. Rizzo

An effective approach for the estimation of the data external to the near-field measurement region in the helicoidal scan is developed in this work. It is based on the nonredundant sampling representations of the electromagnetic field and uses the singular value decomposition method for extrapolating the outside samples. It is so possible to reduce the inevitable truncation error affecting the near-field reconstruction, due to the finite dimension of the helix. Numerical examples assess the effectiveness of the proposed technique.

An introduction to Mobile Station Over-the-Air measurements

Author: Gregory F. Masters

Active antenna measurements are familiar to traditional antenna test range operators. Pulsed, multi-beam, multi-frequency, phased-array measurements have become quite popular for military and space-based applications. These combine typical antenna patterns with active RF excitation in order to create a system-like capability. A new type of measurements called Mobile Station Over-the-Air (OTA) Measurements is emerging, which attempts to include even more of the communication system (antenna, amplifier, receiver and electronics) in the measurement. Promoted by CTIA (Cellular Telecommunications & Internet Association), OTA measurements attempt to test system components closer to the environment in which they will be used. RF excitation is no longer just an RF source in pulsed or CW modes, but requires a Base Station Simulator (BSS) with protocols such as GSM, CDMA, Bluetooth, 802.11g, etc. Traditional antenna patterns are less important than the newly required measurements of TRP (Total radiated power) and TIS (Total isotropic sensitivity). Range operators must become familiar with these concepts in order to keep up with the ever-changing requirements of the future. This paper provides the reader with an overview of Mobile Station OTA measurements, techniques and sample data.

Design of Dielectric Probe for Near-Field Measurement

Authors: Qian Qiaoyuan, Wen Mo

Near-field antenna measurements are carried out within the near-field region of the AUT.

The multiple reflections and mutual coupling is one of the main error sources in the near-field measurements.

Electromagnetic Radome Measurements: A Review of Automated Systems

Authors: Doren W. Hess, Robert Luna, John McKenna

Characterization of radome performance involves measuring the radome-induced changes in the microwave signals that are transmitted and received by the antenna through the radome. The standard quantities that characterize a radome’s performance are Beam Deflection, Boresight Shift, Transmission Efficiency, Change in Antenna Reflection Characteristic, and Pattern Distortion. Typical test system configurations include an RF subsystem and a mechanical positioning subsystem interfaced to a host computer. In this paper we review three types of radome test systems that have been implemented recently − far-field range, compact range, and near-field scanning ranges. We point out the salient features of each. We note the importance of digital automation to making these measurements practical.

Full Sphere Far-Field Antenna Patterns Obtained Using a Small Planar Scanner and a Poly-Planar Measurement Technique

Authors: Stuart F. Gregson, Clive G. Parini, John McCormick

This paper presents an overview of work carried out in developing the probe-corrected, poly-planar near-field antenna measurement technique. The poly-planar method essentially entails a very general technique for deriving asymptotic far-field antenna patterns from near-field measurements taken over faceted surfaces.

The probe-corrected, poly-planar near-field to far-field transformation, consisting of an innovative hybrid physical optics (PO) plane wave spectrum (PWS) formulation, is summarised, and the importance of correctly reconstructing the normal electric field component for each of the discrete partial scans to the success of this process is highlighted. As an illustration, in this paper the poly-planar technique is deployed to provide coverage over the entire far-field sphere by utilising a small planar facility to acquire two orthogonal tangential near electric field components over the surface of a conceptual cube centred about the antenna under test (AUT). The success of the poly-planar technique is demonstrated through numerical simulation and experimental measurement. A discussion into the limitations of the partial scan technique is also presented.

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