Overview
IEC 61338-1-4:2005 specifies standardized measurement methods for determining the complex relative permittivity (real part ε' and loss/imaginary part ε'') of dielectric resonator materials at millimetre‑wave frequencies. The document covers two resonance-based laboratory methods optimized for 30–100 GHz measurements and provides test apparatus, calculation theory, measurement procedures and error/correction guidance.
Key search terms: IEC 61338-1-4, dielectric resonator, millimetre-wave, complex relative permittivity measurement, loss tangent, NRD-guide.
Key Topics & Requirements
- Two measurement methods
- Dielectric rod resonator method excited by NRD‑guide (Non‑Radiative Dielectric waveguide) - full mathematical solution supported by software; suitable for rod specimens placed between conducting plates and coupled to NRD‑guides.
- Cut‑off waveguide method excited by coaxial cables with small loops - uses dielectric plate samples in a cylindrical TE011 cavity; fringe‑field corrections provided.
- Measurement parameters defined
- Real permittivity (ε'), imaginary permittivity (ε''), loss tangent (tan δ = ε''/ε'), temperature coefficient of permittivity (TCH) and temperature coefficient of frequency (TCF).
- The standard relates TCF and TCH accounting for thermal expansion of the specimen.
- Applicable ranges (as stated)
- Frequency: 30 GHz to 100 GHz
- Relative permittivity: approximately 2 to 30
- Loss factor (tan δ): approximately 10^‑6 to 10^‑2
- Equipment and measurement practice
- Scalar or vector network analyzers (vector analyzers recommended for higher precision), NRD‑guide and waveguide transducers, coaxial probes/loops, temperature control setups.
- Procedures include resonance peak identification, energy filling factors, geometric corrections and use of provided correction charts and computational formulas.
- Accuracy and corrections
- Methods target high precision (sub‑percent accuracy for ε') and tight control of loss‑tangent uncertainty. Annexes cover air‑gap error analysis and derivation details; fringe effects and mode charts are provided for correction.
Applications & Users
- Who uses it:
- Materials scientists, microwave/mm‑wave component manufacturers, RF/microwave test laboratories, ceramic and sapphire developers, oscillator and filter designers.
- Practical applications:
- Characterizing dielectric materials for mm‑wave communication (5G/FR2), radar, satellite payloads, sensors, and high‑Q resonator components.
- Providing traceable permittivity and loss data needed for accurate electromagnetic simulation, resonator oscillator design and filter tuning at millimetre‑wave frequencies.
Related Standards
- IEC 61338‑1‑3 - Measurement of complex relative permittivity for dielectric resonator materials at microwave frequency (complements the millimetre‑wave methods in 1‑4).
For implementation, IEC 61338‑1‑4 gives the required apparatus schematics, computation equations and practical correction charts so labs can produce repeatable, comparable millimetre‑wave dielectric property data.