Design of multichannel fringing electric field sensors for imaging. Part I. General design principles

Abstract

Multi-channel electric field sensors are used for electrical impedance and capacitance tomography applications. In cases where only one-sided access can be accommodated, fringing electric field sensors (FEF) sensors are used. The general design principles of multi-channel fringing electric field sensors are discussed in this paper. Analysis of the figures of merit of FEF sensors, such as penetration depth, signal strength, measurement sensitivity, and imaging resolution, are presented. The effects of design parameters on sensor performance are also evaluated. The qualitative design principles described in this part of the paper provide intuitive guidelines for the simulation-based design optimization procedure to be presented in the second part of the paper.

Fringing Electric Field Sensors for Anti-Attack at System-Level Protection

“…The reason is that, as mentioned in Section 2, penetration depth of the fringing electric field sensors’ electric field line is proportional to the length of $\lambda$, which is the distance between the centerlines of the two adjacent driving or sensing electrodes. Penetration depth has an influence on sensor’s measurement range and capacitance’s magnitude, and, when penetration depth increases, the electric field line can reach a farther distance; therefore, the FEF sensor’s measurement range increases [16]. However, penetration depth’s incremental results in sensor’s capacitance magnitude’s decreases.…”

“…Due to possessing these features, the FEF sensor is used in many fields, for example, for soil moisture measurement, making changes in a material’s dielectrics, in motion sensors, to improve a material’s properties and to measure the moisture content of agricultural commodities [13,14,15]. The FEF sensors’ performance is largely impacted by their penetration depth, signal strength, measurement sensitivity and linearity, which are determined by factors such as sensor’s pattern, area and geometrical parameters [16]. …”

A novel approach for road surface wetness detection with planar capacitive sensors

“…An important parameter for interdigital electrode structures is the penetration depth, which is approximately pro-portional to λ (Li et al, 2004). In literature there is no unique definition, but one possible way to evaluate the penetration depth is to study how deep the electric field penetrates into a monitored medium (Da Silva, 2008).…”

Nondimensionalized Parametric Modeling of Fringing Electric-Field Sensors

“…For an FEF sensor of a fixed size, a tradeoff exists between its penetration depth and measurement sensitivity [5]. Increasing electrode width improves the measurement sensitivity of the sensor, but reduces its penetration depth.…”

“…Also, thinner substrates decrease the distance between drive and the backplane, leading to more rapid decay of the electric field. Reduced substrate thickness results in weaker signal strength (terminal impedance measurements) but greater penetration depth [5], [6].…”