Space Difference Magnetic Near-Field Probe With Spatial Resolution Improvement

Abstract

To achieve good spatial resolution, small loop size is required in the traditional loop probe. However, the smaller loop size will lead to lower sensitivity for the probe. In addition, loop size is always limited by the minimum line spacing of the fabrication process. Another problem is that the asymmetric electric field coupling into a probe will not be canceled perfectly even if the structure of this probe is symmetric. To circumvent these problems, a space difference magnetic near-field probe with three kinds of spatial resolutions is proposed in this paper. The probe head including a one-turn loop and a two-turn loop is manufactured in low temperature co-fired ceramics (LTCC). The one-turn loop is clamped with the two-turn loop. Two loops are covered with two shielding ground plates to form a tri-plate structure. The received signals from these two loops are outputted with two SMA connectors through two striplines. The flip-chip junctions with low loss and good shielding capability are used between the probe head and the striplines. The probe characteristics are measured using a 436-m-wide microstrip line with impedance of 50 . Two output ports have different spatial resolutions because two different loops are located above the microstrip line at different height. The proposed probe will have higher spatial resolution when the received signals are outputted in difference. These results are also verified by measuring a 2000-m-wide straight and a 500-m-wide meander microstrip line. The experiment results have good agreement with the simulation results and show the resolution improvement of the difference output of the proposed probe for different lines.Index Terms-Difference output, EMI, magnetic probe, nearfield measurement, spatial resolution improvement.

A pair of parallel differentialmagnetic‐fieldprobes with high measurement accuracy and highelectric‐fieldsuppression ratio

“…19 The measurement accuracy of the proposed differential probes is increased by about 6% compared with that in Reference 14. For EFSR, the proposed probes improves at least 20 dB compared with the single probe in The bandwidth of the proposed probes is larger than that of the stacked differential probes, 21 where the two types of the differential probes have similar size.…”

“…The introduction of differential pairs can effectively improve performance of magnetic probes. In Reference 21, the differential probes with high spatial resolution were proposed, which has stacked differential structure. However, the coupling between the two parts of the differential probes is large at high frequency, which limits operation bandwidth.…”

Symmetrical double‐loop H‐field probe with floating shield for improving sensitivity and electric field suppression

“…The recognition of interference path and ground loop, and the location of interference source have become the main challenges in improving the electromagnetic compatibility of compact electronic products [1][2][3]. A magnetic near-field (H-field) probe acting as a useful near-field diagnostic tool is now widely used for radiation emission measurement [4,5], EMI source localisation [6,7], time-domain voltage and current measurement [8][9][10], and magnetic field measurement [11][12][13][14].…”

A Novel Tangential Electric-Field Sensor Based on Electric Dipole and Integrated Balun for the Near-Field Measurement Covering GPS Band

“…An open-ended monopole can be employed to pick up the normal electric field [12,13,14,15], while the electrically small electric dipole is utilized to detect the tangential electric field [16,17,18] over a surface above the planar circuit. The electromagnetic sensors can effectively sense electromagnetic fields so that there has been increasing attention given to developing high-performance electric-/magnetic-field sensors, such as extending the bandwidth [19,20,21], improving the spatial resolution [22,23,24] and enhancing the sensitivity [25,26,27,28]. Nowadays, there exists a situation where the reconstruction of the interference source based on the dipole moments needs to detect the tangential electric field [29,30].…”