ASTM D2520-21 PDF

Full title and description

Standard Test Methods for Complex Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials at Microwave Frequencies and Temperatures to 1650 °C (Designation: ASTM D2520-21). These test methods define procedures to determine the complex relative permittivity (real part — dielectric constant — and imaginary part — dissipation factor) of nonmagnetic solid dielectric materials using waveguide and resonant-cavity techniques over microwave frequencies and at elevated temperatures up to 1650 °C.

Abstract

ASTM D2520-21 specifies three test methods (A, B, and C) to measure complex permittivity of solid insulating materials across the microwave band (nominally ≈0.5 to 50 GHz) and includes provisions for high‑temperature measurements (special high‑temperature waveguides and resonant cavities up to about 1650 °C). The methods address specimen geometry and placement, measurement procedures, and reporting, and are intended for design, specification acceptance, manufacturing control, and research on ceramics, glasses, and organic dielectrics.

General information

• Status: Active.
• Publication date: April 1, 2021 (designation D2520-21).
• Publisher: ASTM International (ASTM).
• ICS / categories: 29.035.01 (Insulating materials in general).
• Edition / version: D2520-21 (2021 revision; replaces D2520-13).
• Number of pages: 17 pages.

Scope

These test methods cover determination of relative complex permittivity (dielectric constant and dissipation factor) of nonmagnetic solid dielectric materials using three complementary approaches: Test Method A for specimens formed to waveguide internal dimensions, Test Method B for small‑volume specimens placed in a resonant cavity (perturbation technique), and Test Method C for resonant‑cavity measurements with fewer specimen‑size restrictions. The methods apply over the microwave spectrum (approximately 0.5–50 GHz) and include procedures for elevated‑temperature testing using specialized hardware. Users are reminded that the standard does not address all safety concerns associated with high‑temperature electromagnetic testing.

Key topics and requirements

• Definitions and measurement quantities: complex relative permittivity (εr = ε' − jε''), dielectric constant (ε'), and dissipation factor (tan δ or ε''/ε').
• Three test methods: A — waveguide specimen (precisely machined to fit), B — small specimen resonant‑cavity perturbation, C — resonant cavity with relaxed specimen geometry constraints.
• Frequency coverage: general guidance for measurements across microwave frequencies (roughly 0.5 to 50 GHz); note that practical implementation typically requires different generators, waveguides, or cavities for different frequency bands.
• High‑temperature testing: procedures and fixtures for measurements at elevated temperatures (to about 1650 °C) using specially designed waveguides and resonant cavities.
• Specimen preparation and geometry requirements: tight dimensional control for waveguide specimens; controlled placement and small sample volume for perturbation (Method B); reporting of specimen dimensions, orientation, and surface condition.
• Measurement considerations: VNA or microwave sources, calibration, resonant frequency and Q‑factor extraction, corrections for fixture and conductor losses, uncertainty sources and reporting.
• Applications and significance: data used for design calculations of transmission lines, antennas, radomes, resonators, phase shifters, and other microwave components where accurate permittivity vs frequency and temperature is required.

Typical use and users

ASTM D2520-21 is used by materials scientists, electrical and microwave engineers, test laboratories, ceramic and glass manufacturers, PCB and substrate developers, and R&D organizations to characterize dielectric behavior of solid insulators at microwave frequencies and elevated temperatures. Typical uses include specification acceptance testing, service evaluation, manufacturing quality control, and design input for RF/microwave component development.

Related standards

Relevant and commonly cross‑referenced standards include: ASTM D150 (low‑frequency permittivity and dissipation factor test methods), the previous revision ASTM D2520-13, IEC/ISO family documents for dielectric measurements such as IEC 62631‑2‑1 (AC methods to 10 MHz) and more recent microwave/millimeter‑wave methods (for example IEC 63185 and various EN/IEC split‑post or resonator methods for substrate Dk/Df). National and industry standards for PCB substrate permittivity (EN/IEC 61189 series and related EN/IEC documents) are also relevant when testing copper‑clad laminates and substrate materials.

Keywords

complex permittivity, dielectric constant, dissipation factor, microwave, high temperature, resonant cavity, waveguide, perturbation method, Dk, Df, ASTM D2520, dielectric measurement, permittivity vs temperature

FAQ

Q: What is this standard?

A: ASTM D2520-21 is a set of standard test methods for measuring the complex permittivity (dielectric constant and dissipation factor) of solid, nonmagnetic electrical insulating materials at microwave frequencies and at temperatures up to roughly 1650 °C.

Q: What does it cover?

A: It covers three measurement approaches (waveguide specimens, small‑volume resonant‑cavity perturbation, and resonant‑cavity methods with fewer geometry restrictions), guidance on frequency ranges (~0.5–50 GHz in practice), specimen preparation, high‑temperature fixtures, measurement procedures, and reporting.

Q: Who typically uses it?

A: Users include test laboratories, materials and ceramic manufacturers, microwave and RF engineers, PCB/substrate developers, and R&D groups needing accurate permittivity and loss data for design, qualification, and process control.

Q: Is it current or superseded?

A: D2520-21 is the 2021 revision and is listed as the active version of the standard (it supersedes D2520-13). Users should confirm the current status before purchase or use, as standards are periodically reviewed.

Q: Is it part of a series?

A: Yes — it is part of the ASTM D09 committee's collection of standards on electrical insulating materials (Book of Standards Volume 10.02) and is closely related to other permittivity and dielectric property standards such as ASTM D150. It is commonly used alongside IEC/EN measurement methods for microwave and RF substrate characterization.

Q: What are the key keywords?

A: Key keywords are complex permittivity, dielectric constant (Dk), dissipation factor (Df), microwave, resonant cavity, waveguide, perturbation method, high temperature, and dielectric measurement.