SNR Analysis and Optimization in Near-Field Scanning and EMI Applications
In a near-field scanning system, each element of the measurement chain contributes to the thermal noise power density: probe, cables, amplifiers, and the measuring instrument. The signal-to-noise ratio (SNR) is strongly affected by the source output impedance, source temperature, the lossy transmission lines between probe and amplifiers, amplifier noise, amplifier temperature, and amplifier gain. By minimizing the loss between the probe and by using ultralow-noise amplifiers (noise figure (NF) < 0.5 dB), SNR improves by >10 dB, compared to a setup using a 1-m cable and a 3-dB NF amplifier. A resonant probe that is cooled with liquid nitrogen improves measurement SNR by an additional 10-12 dB, as compared to a broadband probe of similar loop size. To combine the advantages of a resonant probe, without sacrificing the ability to measure broadband, a proof of concept is demonstrated that uses a tunable resonant probe which is synchronized to the frequency sweep of the spectrum analyzer.
G. Maghlakelidze and X. Yan and L. Guan and S. Marathe and Q. Huang and B. Bae and C. Hwang and V. Khilkevich and J. Fan and D. Pommerenke, "SNR Analysis and Optimization in Near-Field Scanning and EMI Applications," IEEE Transactions on Electromagnetic Compatibility, Institute of Electrical and Electronics Engineers (IEEE), Jan 2018.
The definitive version is available at https://doi.org/10.1109/TEMC.2018.2792778
Electrical and Computer Engineering
Keywords and Phrases
Cables; Electromagnetic Pulse; Global Positioning System (GPS); Global System for Mobile Communications; Liquid Nitrogen; Nitrogen; Noise Figure; Probes; Signal Interference; Spectrum Analyzers; Thermal Noise; Uncertainty Analysis; Wi-Fi; Field Sensors; Lossy Transmission Line; Measurement Uncertainty; Measuring Instruments; Near Fields; Near-field Scanning; Resonant Probes; Source Temperature; Signal to Noise Ratio (SNR); Electromagnetic Interference (EMI); Field Sensors and Probes; GSM; Near-Field Modeling and Measurements; Probe Cooling
International Standard Serial Number (ISSN)
Article - Journal
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