In today's rapidly evolving electronics landscape, engineers constantly face the dual challenges of high-frequency signal integrity and effective thermal management. Whether you are designing for 5G communications, radar systems, or high-speed digital interfaces, selecting the right substrate material is often the critical factor that determines project success. Today, we are excited to introduce a meticulously engineered double-sided copper PCB built on Isola I-Tera MT40 — a high-performance material platform tailored for your most demanding RF and high-speed digital applications.

Product Specifications: Engineered for Performance

Every detail of this PCB has been carefully optimized to meet the rigorous demands of precision analog and high-frequency circuits.

Material System — Double-sided copper construction using Isola I-Tera® MT40 high-frequency laminate, a thermoset material that bridges the gap between PTFE performance and FR-4 process economics.

Dielectric Thickness — At 0.254mm (10 mil), this substrate thickness is ideally suited for microstrip, coplanar waveguide, and precision impedance-controlled designs, offering a practical balance between manufacturability and electrical performance.

Finished Copper Weight — With 1oz (35μm) copper on both sides, this configuration provides robust current-carrying capacity while maintaining the fine-feature resolution needed for high-frequency trace geometries.

Surface Finish — Immersion silver is specified for its excellent solderability, low contact resistance, and superior flatness — all critical attributes for consistent high-frequency signal transmission and reliable assembly.

Legend and Silkscreen — The top side features oil-free white legend for clear component identification, while the bottom side intentionally omits any legend or ink. This oil-free bottom design eliminates potential dielectric contamination on critical RF paths and provides a pristine surface for heatsink or chassis mounting.

Panel Dimensions — Each panel measures 108mm x 35mm, a compact form factor suitable for module integration and space-constrained applications.

Edge Plating — Specified at designated locations, this metal wrap-around plating provides effective EMI shielding, low-inductance grounding paths, and enhanced mechanical robustness at board edges.

Understanding I-Tera MT40: A Material Science Breakthrough

I-Tera MT40 represents Isola's flagship thermoset laminate solution for high-speed digital and RF/microwave printed circuit designs. Unlike traditional PTFE-based materials that often require specialized handling and costly fabrication processes, I-Tera MT40 delivers comparable or superior electrical performance while remaining fully compatible with standard FR-4 manufacturing lines. This unique combination has made it a preferred choice among design engineers worldwide.

Thermal Performance: Built to Handle the Heat

Modern high-frequency designs pack significant power into increasingly compact footprints. I-Tera MT40 is engineered to withstand these thermal challenges with impressive headroom.

The glass transition temperature of 215°C (measured by DSC) ensures dimensional stability even during lead-free assembly processes, while the decomposition temperature of 360°C provides a wide safety margin for multiple reflow cycles and potential over-temperature events. Perhaps most importantly, the Z-axis coefficient of thermal expansion shows a total expansion of just 2.8% from 50°C to 260°C. This remarkably low expansion significantly reduces the mechanical stress on plated through-holes, virtually eliminating the risk of barrel cracking that often plagues inferior materials in high-reliability applications.

The thermal conductivity rating of 0.61 W/m·K offers a tangible thermal pathway for heat dissipation from active components to ground planes or external heatsinks. This becomes increasingly critical as power amplifiers, processors, and RF front-end modules push higher output power levels in confined board areas.

Electrical Performance: Preserving Signal Fidelity

At the heart of any high-speed design lies the dielectric material's ability to maintain signal integrity across frequency, temperature, and time. I-Tera MT40 excels in this domain with truly industry-leading characteristics.

The dielectric constant measures 3.45 at 2GHz, and what makes this particularly impressive is the material's stability across both temperature and frequency. I-Tera MT40 maintains this Dk value within a tight tolerance from -55°C to +125°C, and up to W-band frequencies extending beyond 75GHz. This eliminates the frustrating "dielectric drift" phenomenon that forces designers to over-design or accept performance degradation under real-world operating conditions. Your impedance calculations made at room temperature will hold true when the board is deployed in the field.

Equally important is the dissipation factor of just 0.0031 at 2GHz. For a non-PTFE thermoset material, this exceptionally low loss tangent is nothing short of remarkable. The direct benefits include reduced insertion loss, minimized crosstalk between adjacent traces, improved signal-to-noise ratios, and better overall system sensitivity. These advantages become increasingly pronounced as data rates exceed 10Gbps or carrier frequencies enter the millimeter-wave spectrum.

Additional electrical properties further reinforce the material's suitability for demanding applications. The volume resistivity of 1.33 × 10⁷ MΩ·cm, surface resistivity of 1.33 × 10⁵ MΩ, and dielectric breakdown voltage of 45.4 kV all speak to a dielectric that maintains its insulating properties under stress. The Comparative Tracking Index rating of Class 3 provides assurance against surface arcing in high-voltage or contaminated environments.

Process Compatibility: The Manufacturing Advantage

Perhaps the most compelling argument for choosing I-Tera MT40 over PTFE-based alternatives lies in its exceptional process compatibility. Standard FR-4 fabrication lines can process this material without any special modifications or dedicated equipment.

Unlike PTFE laminates that require aggressive surface treatments — such as sodium etch or plasma activation — to achieve reliable plated through-hole metallization, I-Tera MT40 accepts conventional desmear and electroless copper deposition chemistries without issue. This translates directly to faster prototyping cycles, shorter production lead times, and significantly lower manufacturing costs. Board shops that are already equipped for FR-4 can deliver I-Tera MT40 designs with minimal setup overhead.

The material also demonstrates excellent compatibility with modern assembly processes. It withstands multiple lead-free reflow cycles without degradation, supports sequential lamination for complex multilayer builds, and exhibits strong resistance to conductive anodic filament formation — a critical reliability factor in high-humidity environments. RoHS compliance and UL V-0 flammability rating complete the qualification checklist for virtually any commercial or industrial application.

Design Considerations for This Specific Configuration

The 0.254mm dielectric thickness paired with 1oz copper creates an ideal environment for 50Ω microstrip transmission lines, yielding a trace width of approximately 0.45mm — a dimension that balances manufacturability with impedance accuracy without pushing fabrication limits.

The immersion silver finish offers distinct advantages for high-frequency applications. Unlike HASL, it provides exceptional planarity for consistent impedance. Compared to ENIG, it eliminates the nickel layer that can introduce magnetic losses at microwave frequencies, while silver's intrinsic conductivity — the highest of any metal — ensures minimal contact resistance at connectors and test points.

Edge plating at designated locations serves multiple critical functions. It creates a continuous conductive barrier for effective EMI shielding, provides a low-inductance path to chassis ground that outperforms conventional via stitching, and resists chipping and delamination during handling. The plated edges also enable castellated connections for board-to-board integration.

The deliberate omission of silkscreen ink from the bottom side is an optimization often overlooked by designers. Legend inks possess their own dielectric properties that can perturb sensitive trace impedances or introduce phase shifts. By keeping the bottom surface completely clear of oil-based inks, this design ensures a predictable and controlled dielectric environment while promoting excellent thermal contact with heatsinks or mounting surfaces.

Application Scenarios

The combination of I-Tera MT40's low-loss properties, 0.254mm dielectric thickness, and edge-plating makes this PCB well-suited for demanding applications across multiple industries.

For 5G and millimeter-wave systems, it serves in antenna feed networks, front-end modules, and beamforming controllers. Test and measurement applications include high-speed ADC/DAC evaluation boards, oscilloscope front-ends, and signal generators. In optical communications, it supports 25G+ transceiver modules and active optical cables.

Automotive radar — particularly 77GHz and 79GHz sensors for ADAS — benefits from the material's thermal stability and CAF resistance. Aerospace and defense applications such as phased array radar, electronic warfare, and SATCOM terminals rely on its wide-temperature stability. For high-speed digital, it handles 100G Ethernet interfaces, PCIe Gen 5/6 test points, and FPGA prototype boards with excellent signal integrity.

Manufacturing and Quality Assurance

Our commitment to quality begins with material traceability — every panel of I-Tera MT40 is sourced through authorized distribution channels with full lot traceability from raw material through finished board. This ensures that you receive genuine Isola material with consistent properties.

Controlled impedance testing is performed on each panel to verify that characteristic impedance values meet design targets. Our automated optical inspection systems detect any trace or pad defects before they become field failures. One hundred percent electrical testing confirms continuity and isolation, while random sample thermal stress testing per IPC-6012 validates the board's ability to withstand assembly and operational temperatures.

We maintain rigorous process controls throughout fabrication to ensure that the 0.254mm dielectric thickness and 1oz copper weight are consistently achieved. Edge plating is inspected for coverage, thickness, and adhesion, with cross-section analysis performed on a regular basis.

Conclusion

The relentless pursuit of higher speeds, lower losses, and greater reliability defines modern electronics design. The choice of PCB substrate material has never been more critical, and I-Tera MT40 delivers PTFE-like electrical performance with FR-4 process economics. Our custom-configured double-sided PCB takes full advantage of this material's capabilities, offering a robust, production-ready platform for your most demanding designs.

Whether you are prototyping next-generation 5G infrastructure, developing precision radar systems, or pushing the boundaries of high-speed digital communications, this I-Tera MT40-based PCB provides the performance headroom you need. The combination of low loss, stable dielectric constant, excellent thermal properties, and straightforward manufacturability accelerates development while reducing risk.

Ready to accelerate your next project? Contact us today to discuss your specific requirements.