A Compact Low-Cost Wideband Shielded-Loop Probe With Enhanced Performance for Magnetic Near-Field Measurements

Bang, Jin Ho; Park, Yuntae; Jung, Kibum; Choi, Jaehoon

doi:10.1109/temc.2019.2946714

Cited by 9 publications

(23 citation statements)

References 13 publications

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“…The sensitivity measures the level of the magnetic field distribution above the device under test. Comparing the achieved sensitivity with the previous results in [ 24 , 25 , 26 , 28 ] shows the main contribution of this work. The proposed probe has summed up the benefits of a large bandwidth with high sensitivity compared to the probes described in the literature reviewed, as illustrated in Table 3 .…”

Section: Isolation and Sensitivitysupporting

confidence: 69%

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Switchable Broadband-to-Tunable Narrowband Magnetic Probe for Near-Field Measurements

Abdulhameed

Kubík

2022

Sensors

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This paper presents a printed magnetic probe that can switch from broadband to tunable narrowband for near-field measurement. In the early design stage, we created a printed loop gap resonator as a magnetic reference sensor for the pre-compliance test in a band up to 6 GHz. Consequently, the results showed a good response in terms of the S11 and S21 parameters of the proposed probe compared with the commercial magnetic sensor XF-R 3-1. The source noise might spread among different frequency bands, making the broadband magnetic probe the closest choice for estimating the magnetic field in the near-field region. Unfortunately, broadband magnetic probes have lower sensitivity than narrowband ones. One of the solutions to get high sensitivity is to connect the LNA to the output of the passive magnetic sensor. This work proposes a novel method to solve this issue using a PIN diode to change the broadband status into a high sensitivity narrowband status and then tune this narrowband across the most critical applications such as 3.5° GHz, 3.75° GHz, 4.8° GHz, and 5.2° GHz with the help of a varactor diode. Compared to the broadband status, an improvement of more than 10 dB has been obtained across all these wireless bands. Furthermore, the proposed structure’s isolation between the electrical and magnetic fields is about 13 dB.

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Section: Isolation and Sensitivitysupporting

confidence: 69%

“…However, this probe suffered from high fluctuations in sensitivity across the whole operating band up to 30 GHz. A small broadband shielded magnetic sensor for near-field measurement was presented in [ 24 ]. The structure was based on an FR-4 substrate and consisted of four stick-up layers.…”

Section: Introductionmentioning

confidence: 99%

Switchable Broadband-to-Tunable Narrowband Magnetic Probe for Near-Field Measurements

Abdulhameed

Kubík

2022

Sensors

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“…The line is terminated in two 100 Ω parallel resistors. Two types of orthogonal responses are evaluated for the loops: E-response and H-response, the first ideally null in shielded and improved magnetic NF probes [12][13][14]. However, electrically small loop probes are sensitive only to the magnetic field [9,15], as long as their radius r follows 2r/λ < 0.01.…”

Section: Near-field Probes and Their Calibrationmentioning

confidence: 99%

Pre-Compliance Near-Field Tests Based on Oscilloscopes

Perotoni,

Silva,

Almeida

et al. 2022

PIER M

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This paper covers the use of oscilloscopes in near-field, pre-compliance radiating tests. Using commercial low-cost planar magnetic probes, a procedure is presented to use the time-domain waveforms to address emitted radiation patterns. In spite of its lower sensitivity in relation to spectrum analyzers, a comparison between the two instruments is presented, with the inferior response of the oscilloscope compensated by means of off-the-shelf broadband amplifiers. Complete system calibration is described and performed, relating the voltage measurements in a transmission-line structure to field amplitudes provided by a full-wave simulation. Two different typical devices are tested using the procedure here developed: a direct current motor, driven by a square wave, and a microprocessor board. Results show the potential use of the almost omnipresent instrument in sophisticated field evaluations, enabling its use in situations where spectrum analyzers are not available.

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“…However, the use of a ferrite material might increase (instead of decrease) the ESL of capacitors, which may degrade the performance of the filter at high frequencies. Also, if the ferrite sheet is placed not between coupled components but a the opposite side of one of them, it may increase coupling between components (this is well known and used as an advantage in other applications [21], [22]). For these reasons, the use of ferrite sheets is more beneficial when used as a plane shield interposed between magnetically coupled components.…”

Section: A Experimental Setup and Circuit Modelsmentioning

confidence: 99%

Improving Performance of Compact EMI Filters by Using Metallic and Ferrite Sheets

González-Vizuete

Bernal-Méndez

Freire

et al. 2021

IEEE Trans. Power Electron.

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Magnetic coupling between components in compact electromagnetic interference filters is one of the main effects that undermine their ability to reduce conducted emissions of power converters at frequencies above several hundreds of kilohertzs or a few megahertzs. This work analyzes and compares the performance of two different shielding strategies based upon the use of copper bands (high-conductivity material) and flexible ferrite sheets (high-permeability material) to improve the attenuation provided by electromagnetic interference filters. We make use of electromagnetic simulations, measurements and modelling with a circuit model of the filter to identify the causes of the limited shielding performance of high-conductivity materials and to quantify the reductions in the mutual inductances between the components of the filter that can be obtained by using a smart arrangement of the shielding structures that is able to overcome these limitations while preserving the compactness of the filter. We also describe a design strategy for electromagnetic interference filters which maximizes the benefits of the proposed shielding techniques. Measurements on several filter prototypes demonstrate that the shielding techniques proposed here can provide 20 to 30dBs increase in the attenuation provided at high frequencies by the electromagnetic interference filter for differential mode noise.

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A Compact Low-Cost Wideband Shielded-Loop Probe With Enhanced Performance for Magnetic Near-Field Measurements

Cited by 9 publications

References 13 publications

Switchable Broadband-to-Tunable Narrowband Magnetic Probe for Near-Field Measurements

Switchable Broadband-to-Tunable Narrowband Magnetic Probe for Near-Field Measurements

Pre-Compliance Near-Field Tests Based on Oscilloscopes

Improving Performance of Compact EMI Filters by Using Metallic and Ferrite Sheets

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