Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
IPC-QF-143: Complete Guide to Quartz Fabric Specifications for RF/Microwave PCB Laminates
When you’re designing a radar antenna substrate or satellite communication PCB operating at 10 GHz and above, standard E-glass reinforcement simply won’t cut it. The dielectric losses become unacceptable, and the signal attenuation degrades system performance. That’s when I first discovered quartz fabric reinforcement and IPC-QF-143. This specification defines woven fabrics made from pure fused silica—99.95% or higher SiO2—that deliver the lowest dielectric losses of any glass-type reinforcement material available for PCB laminates.
IPC-QF-143 is the “Specification for Finished Fabric Woven from Quartz (Pure Fused Silica) for Printed Boards,” published by IPC in February 1992. This 13-page specification covers finished fabrics woven from quartz fiber yarns intended as reinforcing material in laminated plastics for electrical and electronic applications.
Quartz fiber—also known as fused silica fiber or silica glass fiber—represents the highest-purity form of glass reinforcement available for PCB laminates. With a minimum SiO2 content of 99.95%, quartz fabric offers exceptional electrical properties that make it indispensable for RF, microwave, and millimeter-wave circuit applications where signal integrity is paramount.
IPC-QF-143 establishes the nomenclature, definitions, chemical requirements for quartz purity, and physical requirements for finished woven fabrics. The specification provides two tolerance levels for physical characteristics, enabling precise material selection based on design and performance requirements.
Scope and Purpose of IPC-QF-143
IPC-QF-143 establishes comprehensive requirements for woven quartz fabrics used in PCB laminate manufacturing. The specification focuses on ensuring consistent material properties for high-frequency electronic applications where electrical performance is critical.
Key areas covered by IPC-QF-143 include:
Quartz fiber chemical composition requirements (minimum 99.95% SiO2)
Quality assurance provisions and test methods per IPC-TM-650
The specification references ASTM D578 for glass fiber strand requirements and provides detailed appendices covering yarn designation systems and fabric style nomenclature similar to the E-glass specification IPC-4412.
Quartz Fiber Properties and Composition
Quartz fiber possesses a unique combination of electrical, thermal, and mechanical properties that make it the premier reinforcement choice for high-frequency PCB applications. Understanding these properties explains why quartz commands a significant price premium over conventional glass reinforcements.
Ultra-High Purity Composition
IPC-QF-143 specifies a minimum SiO2 content of 99.95%, making quartz fiber essentially pure fused silica. This ultra-high purity eliminates the metallic oxide impurities (such as sodium, potassium, and iron oxides) present in E-glass that contribute to dielectric losses at high frequencies. Commercial quartz fibers like JPS Astroquartz and Saint-Gobain Quartzel achieve 99.99% purity levels.
Exceptional Dielectric Properties
Quartz fiber exhibits a dielectric constant (Dk) of approximately 3.7-3.8 at frequencies from 1 MHz to 10 GHz—significantly lower than E-glass at 6.0-7.0. More importantly, the dissipation factor (Df) or loss tangent is extraordinarily low at 0.0001-0.0002 at 10 GHz, compared to 0.002-0.004 for E-glass. This ultra-low loss tangent makes quartz the material of choice for RF and microwave circuits where signal attenuation must be minimized.
Near-Zero Thermal Expansion
Fused silica has one of the lowest coefficients of thermal expansion of any material—approximately 0.5 ppm/°C, compared to 5.0 ppm/°C for E-glass. This near-zero CTE provides exceptional dimensional stability under thermal cycling and eliminates thermal shock concerns. Quartz components can be rapidly quenched from over 1000°C without damage.
High Temperature Capability
Quartz fiber maintains its properties at temperatures exceeding 1000°C and softens at approximately 1200°C (compared to E-glass softening at 850°C). This extreme temperature resistance makes quartz suitable for aerospace applications where thermal protection is required, including radome structures that must withstand aerodynamic heating.
Quartz vs Glass Fiber Property Comparison:
Property
Quartz (SiO2)
E-Glass
S-Glass
SiO2 Content
99.95%+
52-56%
64-66%
Dk @ 10 GHz
3.7-3.8
6.0-7.0
5.0-5.5
Df @ 10 GHz
0.0001-0.0002
0.002-0.004
0.001-0.002
CTE (ppm/°C)
0.5
5.0
2.9
Density (g/cm³)
2.2
2.54
2.49
Softening Point
1200°C
850°C
1050°C
Relative Cost
10-15x
1x (baseline)
3-5x
RF and Microwave PCB Applications
The exceptional dielectric properties of quartz fabric make it the preferred reinforcement for high-frequency electronic applications where signal integrity and low loss are critical requirements.
Radome Structures
Radomes—the protective enclosures covering radar antennas—represent the signature application for quartz fabric. The combination of electromagnetic transparency (low Dk and ultra-low Df), mechanical strength, and thermal stability makes quartz composites ideal for radome construction. Commercial aviation weather radar, military targeting systems, and satellite communication antennas all utilize quartz-reinforced radomes to minimize signal degradation while protecting sensitive electronics.
Antenna Substrates
Patch antennas, phased array elements, and other printed antenna structures benefit significantly from quartz-reinforced substrates. The low and stable dielectric constant enables precise impedance control across wide frequency ranges, while the ultra-low loss tangent maximizes antenna efficiency. Applications include Ku-band and Ka-band satellite communication systems operating at 12-40 GHz.
Microwave Circuit Substrates
Quartz-reinforced laminates combined with PTFE or cyanate ester resin systems provide excellent substrates for microwave integrated circuits. The low Dk enables tighter trace spacing and thinner dielectrics while maintaining impedance control. Applications include radar front-end modules, satellite transponders, and 5G millimeter-wave base station equipment.
Aerospace and High-Reliability Applications
Thermal Protection Systems
Quartz fiber’s exceptional temperature resistance—maintaining properties above 1000°C—makes it valuable for thermal protection applications in aerospace. Quartz fabric composites are used in re-entry vehicle thermal protection, missile radomes subject to aerodynamic heating, and high-temperature insulation where electrical transparency is also required.
Satellite Electronics
Space-qualified electronics demand materials with dimensional stability across extreme temperature cycling, low outgassing, and radiation resistance. Quartz fabric’s near-zero CTE provides exceptional dimensional stability from cryogenic temperatures to high operating temperatures. The pure SiO2 composition also resists degradation from space radiation better than conventional glass.
Military and Defense Systems
Military radar systems, electronic warfare equipment, and guidance systems utilize quartz-reinforced substrates for their combination of RF performance and environmental durability. Applications include airborne radar, shipboard communication systems, and precision guidance electronics where performance cannot be compromised.
Several manufacturers produce high-purity quartz fabrics conforming to IPC-QF-143 requirements. These products are typically certified to aerospace material specifications such as AMS 3846.
JPS Composite Materials – Astroquartz
JPS pioneered high-purity silica fabric for the aerospace industry and remains a world leader in quartz fabric production. Their Astroquartz II and Astroquartz III product lines offer 99.99% pure fused silica with 9μm fiber diameter. Products include woven fabrics, chopped fibers, and rovings for various composite manufacturing processes.
Saint-Gobain – Quartzel
Saint-Gobain Advanced Ceramic Composites (formerly Saint-Gobain Quartz) produces Quartzel yarns and fabrics with 99.95%+ SiO2 purity. Their product range includes multiple fiber diameters (9-14μm) and specialized sizings compatible with epoxy and cyanate ester resin systems for radome and antenna applications.
Quartz-Reinforced Laminate Systems
Laminate manufacturers combine quartz fabric with various resin systems to create finished substrates. Common combinations include quartz/PTFE for ultra-low loss applications, quartz/cyanate ester (referenced as CEQ type in material databases) for high-temperature microwave circuits, and quartz/polyimide for flexible high-frequency applications. These products are specified under IPC-4103 for high-speed/high-frequency base materials.
Base Materials for High Speed/High Frequency Applications
IPC-4101
Base Materials for Rigid and Multilayer Printed Boards
ASTM D578
Glass Fiber Strands Specification
AMS 3846
Aerospace Material Specification for Quartz Fabric
Frequently Asked Questions About IPC-QF-143
What is the difference between quartz and E-glass for PCB laminates?
Quartz (pure fused silica, 99.95%+ SiO2) offers dramatically superior electrical properties compared to E-glass (52-56% SiO2). The key differences are dielectric constant (Dk 3.7 vs 6.5), loss tangent (Df 0.0002 vs 0.003), and CTE (0.5 vs 5.0 ppm/°C). Quartz costs 10-15x more than E-glass, so it’s reserved for applications where RF performance justifies the premium—typically above 5-10 GHz operating frequency.
When should I specify quartz fabric instead of PTFE for RF applications?
PTFE-based laminates offer lower Dk (2.0-2.2) but have poor dimensional stability and high CTE. Quartz-reinforced laminates provide a balance: lower Dk than E-glass (3.7 vs 6.5), exceptional dimensional stability from near-zero CTE, and compatibility with high-temperature processing. Choose quartz when you need both excellent RF properties AND dimensional stability for fine-pitch features, or when the application requires high-temperature capability.
What frequency range benefits most from quartz fabric reinforcement?
Quartz fabric provides the greatest benefit at microwave and millimeter-wave frequencies—typically 10 GHz and above. At these frequencies, the ultra-low loss tangent (0.0001-0.0002) significantly reduces signal attenuation compared to E-glass (0.002-0.004). For Ku-band (12-18 GHz), Ka-band (26-40 GHz), and 5G millimeter-wave (28-39 GHz) applications, the performance improvement justifies the cost premium.
Is quartz fabric more difficult to process than standard glass fabric?
Quartz fabric requires careful handling but isn’t dramatically harder to process than E-glass. Key considerations include: avoiding alkali contamination (remove fingerprints with alcohol before processing), using compatible sizing chemistry for your resin system, and proper moisture control during lamination. Drilling and routing are similar to glass, though quartz’s hardness causes somewhat faster tool wear.
Where can I purchase IPC-QF-143 and quartz fabric products?
IPC-QF-143 is available from the IPC Store (shop.ipc.org) for approximately $79. For quartz fabric products, major suppliers include JPS Composite Materials (Astroquartz product line), Saint-Gobain Advanced Ceramic Composites (Quartzel products), and specialty high-frequency laminate suppliers. Finished quartz-reinforced laminates are available from Rogers Corporation, Taconic, and other RF laminate manufacturers—specify materials under IPC-4103 slash sheets that include quartz reinforcement.
Conclusion
IPC-QF-143 defines the woven quartz fabrics that enable PCB laminates with the lowest dielectric losses available from any glass-type reinforcement. The ultra-high purity (99.95%+ SiO2) of quartz fiber delivers exceptional properties: dielectric constant of 3.7-3.8, loss tangent as low as 0.0001, near-zero CTE of 0.5 ppm/°C, and temperature capability exceeding 1000°C.
For RF and microwave circuits operating at 10 GHz and above—including radomes, satellite communication systems, phased array antennas, and 5G millimeter-wave equipment—quartz-reinforced laminates per IPC-QF-143 provide the signal integrity that demanding applications require. While the 10-15x cost premium over E-glass limits quartz to specialized applications, the performance improvement is essential when ultra-low loss and dimensional stability determine system success.
Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
