Optimizing Measurement SNR for Weak Near-Field Scanning Applications
Conventional near-field scanning techniques often employ a general setup such as: broadband near-field probe output connected to a chain of amplifiers through a coaxial cable to a spectrum analyzer. In this paper, we investigated how the signal to noise ratio is influenced by the coaxial connection between the probe output and the first amplifier, types of probes, cooling the probes with liquid nitrogen and the amplifier's noise figure. Eliminating cabling between probe and first amplifier, and using a low noise amplifiers helped increase signal-to-noise ratio by ~10dB. Further, liquid nitrogen is used to cool down a tunable resonant probe. This increases quality factor of the resonance and improves sensitivity. Thus, SNR is further improved by 10-12dB compared to a similar broadband setup.
L. Guan et al., "Optimizing Measurement SNR for Weak Near-Field Scanning Applications," Proceedings of the 2017 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (2017, Washington, DC), pp. 687-691, Institute of Electrical and Electronics Engineers (IEEE), Aug 2017.
The definitive version is available at http://dx.doi.org/10.1109/ISEMC.2017.8077955
2017 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (2017: Aug. 7-11, Washington, DC)
Electrical and Computer Engineering
Keywords and Phrases
Electromagnetic Compatibility; Global Positioning System (GPS); Global System for Mobile Communications; Liquid Nitrogen; Liquids; Low Noise Amplifiers; Magnetic Field Measurement; Nitrogen; Noise Figure; Probes; Scanning; Spectrum Analyzers; Near Field Probes; Near-field Scanning; Quality Factors; Resonant Probes; Signal to Noise Ratio (SNR); EMI; GSM; Magnetic Field Measurement; Probe Cooling
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