Advantages of Very-Near-Field Antenna Measurement
Traditional near- and far-field measurement systems require ongoing maintenance and calibration, but none is needed with very-near-field measurements systems like the RFxpert. Likewise, many chambers require a reference antenna, but none is needed for very-near-field measurements. Perhaps most importantly for design workflows and accelerating time-to-market, the RFxpert delivers results right in the design area in less than a second.
The compact size of the RFxpert means that it can be used almost anywhere. It is literally a bench top antenna measurement system. Despite its small size, the RFxpert maintains excellent accuracy for both patterns and absolute far-field parameters.
The RFxpert overcomes the traditional limitations of the planar scanner for non-directional antennas in the hemisphere by using the close proximity of the AUT to the scan surface to create a large angular coverage. By conducting a second back-side measurement, a design team can obtain complete spherical results.
The far-field results produced from very-near-field measurements offer a variety of user-selectable metrics including gain, radiated power, efficiency, directivity, and axial ratio.
The following test results verify that very-near-field projections can compare favorably with actual far-field results. Variations between the two demonstrate a consistent range of ± 1.5 dB.
Test Results #1-3: Compares very-near-field projections to actual far-field results for three different cell phones in the typical mobile phone frequency range.
Test Result #4: The y-axis reports RFxpert very-near-field data projected to far-field results versus the x-axis which reports traditional near-field results projected to far-field. These results confirm that very-near-field WDCMA Low Bands and WiFi measurements at 2.4 GHz correlate with far-field measurements to within ± 1.5 dB.
EMSCAN is the world leading developer of FAST magnetic very-near-field measurement technologies and applications since 1989, providing real-time test solutions to antenna and PCB designers and verification engineers, without the need for a chamber.
The EMxpert, a family of compact EMC and EMI diagnostic tools, and the RFxpert, a family of antenna measurement tools, enable engineers to quickly optimize their designs. EMSCAN solutions dramatically increase designer productivity and substantially reduce time-to-market and project development costs. www.emscan.com