Skip to main content


Corporate InformationResearch & Development

September 3, 2013

Report from Presenter

The IEEE International symposium on Electromagnetic Compatibility (EMC) 2013 was held in Denver, Colorado, United States between Aug. 5th and 9th. The symposium was one of the biggest conferences on EMC including more than 250 presentations. Yokohama Research Laboratory, Hitachi Ltd., made a presentation entitled "Double Position-Signal-Difference Method for Electric Near-Field Measurements".

Fig. 1 Electric near-field measurement
and its applications


Recently the number of wireless functioned portable devices such as smart-phone and/or tablet increased in the market as well as electric vehicle or electrified automotive. The technology for the electromagnetic compatibility (EMC) is getting more important based on the background. Electric near-field measurement is one of the key technologies for the EMC to understand the mechanism and/or noise propagation paths. Although the critical parameter for the measurement is the spatial resolution, conventionally the fabrication of miniaturized probe is required for high spatial resolution measurements.

We focused on the PSD (Position Signal Difference) method which allows obtaining arbitrary spatial resolution using just one probe measuring with two sets of heights of probe. Calculation of the subtraction between two sets of measured data provides the measured result related to equivalent miniaturized probe. However, this conventional PSD method provides only normal component of electric near-field but tangential component. The DPSD (Double Position Signal Difference) method which we proposed here simply derive tangential component by subtracting PSD applied result from original measured result. The proposed method was theoretically described and verified by measurements.

Fig. 2 Characterization of DPSD method

Fig. 3 PSD and DPSD applied results

By taking the proposed DPSD method, intended spatial resolution can be obtained without changing the probe. We, Yokohama Research Laboratory, continue developing reliable and low-noise design techniques utilizing these kinds of electromagnetic measurement technologies.

(By FUNATO Hiroki)

  • Page top