Design of Miniature Active Magnetic Probe for Near-Field Weak Signal Measurement in ICs

An active magnetic field probe is proposed in this letter for use in near-field measurement in ICs. The probe is fabricated in a four-layer printed circuit board (PCB), and an amplification circuit is integrated on the top layer of the probe. Compared with commercial probe, the proposed probe has high sensitivity and miniature size and can be used to detect weak signals in narrow and complex spaces. The maximum size of the probe is less than 60 mm $\times19$ mm. The transfer factor is enhanced by 39 dB. The working band (9 kHz–1 GHz) is enough to locate the fault points in most engineering applications. Compared with the passive probe, the proposed probe is much compatible with modern IC diagnosis. In addition, a new calibration is proposed to obtain an accurate calibration coefficient. It is necessary for many applications, which need high precision near-field data.