Overview
IEC 62899-202-3:2019 specifies a standard contactless method for measuring the sheet resistance of printed conductive films using an eddy-current (RF) probe. Part of the IEC 62899 printed electronics series, this standard defines terms, specimen requirements, apparatus characteristics and a recommended measurement procedure for conductive ink films where electrical contact is impractical or undesirable.
Key topics and technical requirements
- Measurement principle: contactless eddy-current (RF) coupling that induces eddy currents and relates the RF drive response to conductivity × thickness (σ·t).
- Measurement range: specified sheet resistance from 0.01 Ω/□ to 1 000 Ω/□ (ohms per square).
- Film thickness: films ≥ 5 nm are within scope (see Annex C for thickness effects).
- Specimen & substrate:
- Conductive layer must be continuous with no underlying conductive patterns.
- Substrate must be insulating (polymers, paper, glass) with effective sheet resistance at least 1 000× that of the film.
- Specimen size must be at least twice the probe size to avoid edge effects.
- Apparatus:
- Eddy-current gauge comprising an RF generator and ferrite-core probe(s).
- Recommended RF frequency coverage: 40 kHz–10 MHz to span a broad resistance range.
- Two probe architectures: dual and single probe types (both accepted; Table 1 in the standard compares them).
- Test procedure & reporting:
- Clauses cover sample staging, allowable gap, environmental/test conditions and required report items (test environment, apparatus, test conditions and results).
- Annexes provide comparisons with the 4‑point probe method (Annex A), probe-position edge effects (Annex B) and film thickness influence (Annex C).
Applications and users
This standard is especially valuable for:
- Manufacturers and R&D teams in printed electronics, flexible circuits, transparent conductive films and conductive inks.
- Quality assurance and metrology labs needing non-contact sheet resistance measurement.
- Use cases where a 4‑point probe cannot be used - e.g., films covered by insulating layers, micro/nanostructured surfaces or fragile devices.
Benefits include fast, repeatable contactless testing and suitability for production-line or in-line inspection.
Related standards
- IEC 62899-202 (Printed electronics - Materials - Part 202: Conductive ink)
- References in the standard also cite terms from IEC TS 61836 and IEC TS 62607‑2‑1 (see normative references and definitions).
Keywords: IEC 62899-202-3:2019, printed electronics, conductive ink, sheet resistance, eddy-current, contactless measurement, 4-point probe, RF probe, non-contact metrology.
Open preview (PDF)Printed electronics - Part 202-3: Materials - Conductive ink - Measurement of sheet resistance of conductive films - Contactless method
