Nearfield Systems Inc. (NSI), the leader in antenna measurement systems.

NSI's products are designed and manufactured specifically for near-field and far-field antenna measurements to meet real-world customer demands. The designs are the result of over 75 man-years of near-field experience and have set the standard for accuracy, reliability, and value. NSI's technical engineering staff has expertise and applications knowledge to integrate the right solutions for your test requirements; from RF subsystems to near-field scanners, far-field positioners, processing software applications, and chamber integration requirements.

A multi-disciplinary team of highly skilled experts and scientists provide technical services support to our customers. Specific areas of applications expertise include:

NSI's products are designed and manufactured to meet the highest standards for reliability and productivity. NSI also provides:

Near-Field Education Programs

NSI provides a formal near-field antenna training course lasting multiple days. This course covers near-field theory, antenna measurement applications, alignment techniques, NSI software and system maintenance aspects.

Refurbishment Program

NSI offers this service to its customers who have a need to refurbish or upgrade their existing systems. This service is for customers whose methods of testing have changed, or seek cost effective ways to extend older system life usage.

Antenna Test Services

NSI offers two state-of the-art test chambers at the Torrance, CA facility for testing antenna apertures up to 12' (3.7m) in diameter from 400 MHz to 50 GHz. These chambers include planar, cylindrical and spherical near-field test solutions, the latest NSI 2000 professional software and high performance RF instrumentation.

Chamber No. 1 includes a NSI-300V-12x12 Vertical Planar Near-field Scanner with cylindrical and spherical scanning options. Use of 36” pyramidal absorber on the back wall of the chamber permits high quality measurements down to L-band. This system includes an NSI Panther-based RF subsystem that can take measurements over the 1 to 50 GHz range, and supports both pulse measurement capability and multi-port AUT PIN switching for measurement speeds up to 2 million points per second.

Chamber No. 2 features the NSI-700S-75 Spherical Near-field Scanner for testing medium and low gain antennas up to 60 inches (1.52 m) in diameter and is ideally suited to perform cellular and PCS band base-station antenna testing down to 400 MHz.

NSI antenna test services are performed in close cooperation with the customer. Antenna radiation patterns, gain and polarization properties are measured. A full test report with measured data is delivered. Near-field probe characterization can form part of this activity and complete probe correction data files supplied. Please contact the NSI sales group for further details.

Range Alignment and Maintenance

Antenna measurement systems require periodic maintenance and alignment to maintain system performance and accuracy. NSI offers this service, see NSI-SU-5000, for all of our scanner systems including system inspection, lubrication and certified alignment. This service is especially recommended for systems that are heavily used and for those that have been recently relocated.

Range Evaluation

Any antenna range, near-field or far-field, is subject to error sources which must be carefully analyzed or evaluated. The near-field industry has adopted an evaluation technique based on a set of error terms first proposed by NIST (“Error Analysis Techniques for Planar Near-field Measurements”, IEEE Trans. Antenna and Prop. Vol. 36, no. 6, June 1988, by Allen Newell).

These 18 terms are typically evaluated by a combination of analysis and tests. NSI has extensive experience in performing complete range evaluations for gain, side lobes levels, cross-pol levels, and beam pointing errors. During system installation and training, we typically include a brief overview of the range evaluation process. A complete range accuracy evaluation including all testing, analysis, and summary report can be quoted as an optional service.

The following table shows an example of the results of the range evaluation on one of NSI’s large near-field ranges used for testing the Globalstar satellite antennas.