From the material presented here, it is clear that the theory underlying the SNF approach is complex and involved to implement. However, it is also very elegant and provides one with many measurement options and powerful capabilities. The numerical implementation of the theory can be efficiently deployed through the use of the fast Fourier transform (FFT) enabling transforms of even electrically large antennas to be accomplished in a matter of a few seconds on a modern powerful digital computer. With the advent of commercially available SNF test systems, the user can exploit these techniques, largely unimpeded by the burden of the theory or the implementation thereof. The material presented here highlighted some of the fundamental concepts and limitations the user needs to be aware of in order to use these test systems with confidence.

Chapter Contents:

• 7.1 Introduction
• 7.2 Types of SNF ranges
• 7.2.1 Roll over azimuth - (ø/θ) systems
• 7.2.2 Swing arm - (θ/ø) systems
• 7.2.3 Arch-roll rotated - (θ/ø) systems
• 7.2.4 Articulating arm - (θ/ø) systems
• 7.2.5 Robotic arm SNF systems
• 7.3 A Solution to Maxwell's equations in spherical coordinates
• 7.4 Relating spherical mode coefficients to spherical near-field data
• 7.5 Sampling requirements and spherical mode truncation
• 7.6 Development of the transmission formula
• 7.7 Near-field probe correction
• 7.8 Far-field expressions
• 7.9 Practical acquisition schemes and examples
• 7.10 Summary
• References

Inspec keywords: antenna testing; near-field communication; fast Fourier transforms

Other keywords: FFT; electrically large antennas; modern powerful digital computer; fast Fourier transform; SNF approach; spherical near-field antenna measurements

Subjects: Single antennas; Other radio links and systems; Integral transforms