Everything you need to know about Arlon DiClad 870 — full electrical and mechanical specs, how it compares to DiClad 880 and DiClad 527, fabrication requirements for PTFE processing, and design tips for radar, base station, and phased array applications.
Every experienced RF PCB designer has run into the same compromise at some point: the substrate that gives you the best electrical numbers is often the one that causes the most headaches in fabrication and the most variance in production. DiClad 880 is a perfect example — Dk 2.17, dissipation factor as low as 0.0009 at 10 GHz, but soft, dimensionally challenging, and unforgiving if your fabricator’s PTFE process isn’t dialed in. Go the other direction toward DiClad 522 or 527 and you get excellent mechanical stability, but the Df creeps up to 0.0018.
Arlon DiClad 870 lives exactly in the middle. With a nominal Dk of 2.33 and a Df of 0.0013 at 10 GHz, it gives up a modest amount of loss performance compared to DiClad 880 in exchange for meaningfully better dimensional stability and mechanical robustness. For a very wide range of radar feed networks, base station antennas, LNA boards, and phased array circuits, that is a trade worth making — and DiClad 870 has a strong installed base in military and commercial high-frequency electronics to prove it.
This complete review covers the material composition, full specification profile, where DiClad 870 sits in the broader Arlon/Rogers DiClad family, what to watch for during fabrication, and how to use it well in real designs.
What Is Arlon DiClad 870?
Arlon DiClad 870 is a woven fiberglass reinforced, PTFE-based composite laminate originally developed by Arlon Materials for Electronics and now produced and marketed under the Rogers Corporation brand following Rogers’ acquisition of Arlon. It is part of the DiClad series — a family of PTFE/woven-glass composites distinguished by precise control of the fiberglass-to-PTFE content ratio across different products.
DiClad 870 uses a medium fiberglass-to-PTFE ratio, specifically engineered to reduce the dielectric constant and dissipation factor compared to the higher-glass DiClad 522/527 products, while retaining more dimensional stability than the very-high-PTFE DiClad 880. The result is a Dk of 2.33 — the same nominal value as Arlon CuClad 233 and IsoClad 933 — with a Df of 0.0013 at 10 GHz that clearly outperforms any thermoset laminate in its class.
One structural point worth establishing early: DiClad materials, including DiClad 870, use parallel-plied construction. All PTFE-coated fiberglass plies are aligned in the same direction. This distinguishes them from CuClad products, which use cross-plied construction for true X-Y isotropy. For most filter, coupler, power divider, and LNA board applications, parallel-plied construction is entirely adequate. Only when your design requires symmetric electrical behavior in orthogonal directions — certain phased array and balanced circuit topologies — does the parallel-plied construction of DiClad 870 become a constraint.
Working with quality Arlon PCB fabricators who have PTFE processing experience is essential when using DiClad 870 in production.
Arlon DiClad 870 Full Specification Table
The following table presents the typical electrical, mechanical, and environmental properties for Arlon DiClad 870. These are typical values from the Rogers/Arlon datasheet and published material databases. They are not to be used as specification limits. Always verify against the current official datasheet for your specific thickness and lot.
| Property | Value | Test Method |
| Dielectric Constant (Dk) @ 10 GHz | 2.33 | IPC TM-650 2.5.5.5 |
| Dissipation Factor (Df) @ 10 GHz | 0.0013 | IPC TM-650 2.5.5.5 |
| Dissipation Factor (Df) @ 1 MHz, 50% RH | 0.0009 | IPC TM-650 2.5.5.3 |
| Thermal Coefficient of Dk (TCDk) | -161 ppm/°C (-10 to 140°C) | IPC TM-650 2.5.5.7 |
| CTE (X-axis) | 17 ppm/°C | IPC TM-650 2.4.41 |
| CTE (Y-axis) | 29 ppm/°C | IPC TM-650 2.4.41 |
| CTE (Z-axis) | 217 ppm/°C | IPC TM-650 2.4.41 |
| Moisture Absorption | 0.02% | IPC TM-650 2.6.2 |
| Copper Peel Strength (1 oz, 10s @ 288°C) | 14 lbs/in | IPC TM-650 2.4.8 |
| Arc Resistance | > 180 seconds | ASTM D495 |
| UL Flammability Rating | UL94-V0 | UL94 |
| NASA Outgassing (TML) | 0.01% | NASA SP-R-0022A |
| NASA Outgassing (CVCM) | 0.01% | NASA SP-R-0022A |
| Ply Orientation | Parallel-plied | — |
| Construction Type | Woven fiberglass / PTFE composite | — |
The 0.02% moisture absorption value is worth calling out specifically. This is among the lowest moisture absorption figures in the PTFE laminate category — genuinely exceptional performance for an outdoor or aerospace substrate. The NASA outgassing values (TML 0.01%, CVCM 0.01%) are similarly low, qualifying DiClad 870 for use in vacuum and space-adjacent environments where outgassing threatens optical or sensor performance.
Available Thickness Options for Arlon DiClad 870
DiClad 870 is available across a practical range of standard substrate thicknesses. The table below reflects standard configurations from the Arlon/Rogers materials guide.
| Thickness (inches) | Thickness (mm) | Notes |
| 0.010″ | 0.254 | Thin, suitable for compact multilayer RF signal layers |
| 0.020″ | 0.508 | Most common for 2-layer microwave circuits |
| 0.031″ | 0.787 | Standard microstrip and stripline work |
| 0.047″ | 1.194 | Moderate substrate for LNA and coupler boards |
| 0.062″ | 1.575 | Common for power dividers and combiners |
| 0.125″ | 3.175 | Thick substrates, structural applications |
Copper cladding is available in ½ oz, 1 oz, and 2 oz electrodeposited (ED) copper on both sides as standard offerings. Rolled annealed (RA) copper may be available on request and is worth considering for designs operating above 20 GHz, where the smoother surface profile of RA foil reduces conductor-dominated loss. Master sheet sizes are available up to 36″ × 72″, which supports multi-circuit panel layouts for volume production.
Understanding the Medium Fiberglass/PTFE Ratio in DiClad 870
The engineering principle that defines DiClad 870’s position in the DiClad family is worth understanding in practical terms, not just as a specification number.
Pure PTFE has a dielectric constant of approximately 2.1 and essentially no dielectric loss at microwave frequencies. As you add woven fiberglass reinforcement — which has a Dk in the 5–6 range — you raise the composite Dk and introduce a small amount of additional loss. You also gain dimensional stability, improved registration, and better mechanical handling. The fiberglass-to-PTFE ratio is therefore a tunable parameter that allows Arlon/Rogers to offer a range of PTFE-based products at different operating points.
DiClad 870 uses fewer plies of woven fiberglass and a higher ratio of PTFE content compared to DiClad 527 or DiClad 522, but more glass than DiClad 880. This produces a Dk of 2.33 — which is both lower and more electrically favorable than the DiClad 527 range of 2.40–2.65 — while preserving significantly better dimensional behavior than DiClad 880. The Df of 0.0013 at 10 GHz represents a clear improvement over DiClad 527’s 0.0018, and while it doesn’t quite match DiClad 880’s 0.0009, the gap is modest for the majority of application budgets.
In practical design terms, a system noise figure impact from the DiClad 870 vs. DiClad 880 loss difference is typically well under 0.1 dB for a few inches of transmission line at X-band — easily within normal design margin. What that step from DiClad 880 to DiClad 870 gets you in return is noticeably better panel-to-panel dimensional consistency and a substrate that is less likely to cause registration problems in multilayer builds or dimensional yield issues in high-volume antenna production.
Arlon DiClad 870 vs. DiClad 880 vs. DiClad 527: Choosing the Right Product
The most common material selection decision involving DiClad 870 is a three-way comparison with its immediate neighbors in the DiClad family. The table below lays out the key parameters side by side.
| Parameter | DiClad 527 | DiClad 870 | DiClad 880 |
| Nominal Dk @ 10 GHz | 2.40 – 2.65 | 2.33 | 2.17 – 2.20 |
| Df @ 10 GHz | 0.0018 | 0.0013 | ~0.0009 |
| Fiberglass/PTFE Ratio | Higher glass | Medium glass | Lower glass |
| CTE X-axis (ppm/°C) | ~14 | 17 | Higher |
| Moisture Absorption | 0.03% | 0.02% | Higher |
| Dimensional Stability | Best in series | Good | Lower |
| Mechanical Robustness | Most robust | Good | Softer |
| Ply Orientation | Parallel | Parallel | Parallel |
| Best Application Fit | High-vol production, stability | Balanced loss + stability | Lowest loss priority |
The decision between DiClad 870 and DiClad 880 almost always comes down to loss budget versus fabrication risk. If your system noise figure analysis shows that Df 0.0009 is genuinely required to meet the specification — common in precision receive chains for scientific instruments, some defense radar systems, or very long-run test fixtures — then DiClad 880 is the right choice and you should work with a fabricator who regularly processes very-high-PTFE substrates. If the 0.0013 Df of DiClad 870 achieves your loss budget with margin to spare, the improved dimensional stability and slightly better moisture performance make DiClad 870 the more practical and reliable production choice.
The choice between DiClad 870 and DiClad 527 is generally straightforward: DiClad 870 has better electrical performance (lower Dk and lower Df) at the cost of slightly reduced dimensional stability versus DiClad 527. If your application demands the better loss numbers and your fabricator is comfortable with PTFE processing, DiClad 870 is the right move. If you’re in a high-volume production environment where dimensional yield drives unit economics, DiClad 527 may win even though its Df is 38% higher.
How Arlon DiClad 870 Compares to Other Brands at Dk 2.33
DiClad 870 is not the only product targeting the Dk 2.33 market. The following comparison helps position it against frequently considered alternatives.
| Material | Manufacturer | Dk | Df @ 10 GHz | Ply Type | Notes |
| DiClad 870 | Rogers/Arlon | 2.33 | 0.0013 | Parallel | Medium PTFE, balanced |
| CuClad 233 | Rogers/Arlon | 2.33 | 0.0013 | Cross-plied | X-Y isotropic version of same Dk |
| IsoClad 933 | Rogers/Arlon | 2.33 | ~0.0015 | Non-woven random | Flexible/conformal applications |
| Rogers RT/duroid 5870 | Rogers | 2.33 | 0.0012 | PTFE/microfiber | Non-woven, similar Df |
| Rogers RO4003C | Rogers | 3.55 | 0.0027 | Thermoset | Much higher Dk, not directly comparable |
| Standard FR4 | Various | 4.2–4.5 | > 0.020 | Thermoset | Not suitable above ~1 GHz |
DiClad 870 and CuClad 233 share the same Dk and very similar Df, but the construction differs. CuClad 233 uses cross-plied construction for X-Y isotropy, making it the preferred choice when true isotropy is needed. DiClad 870’s parallel-plied construction provides better Dk uniformity in the laminate plane along the fiber direction, which can be advantageous for circuits that predominantly run in one direction. For most standard filter, LNA, and coupler designs, either material performs equivalently and the choice may come down to panel format preferences or fabricator experience.
Typical Applications for Arlon DiClad 870
DiClad 870’s application profile reflects its balanced position in the DiClad family: low enough loss for demanding RF circuits, stable enough for production-level manufacturing and outdoor/field deployments.
| Application Category | Specific Use Cases |
| Military Radar | Radar feed networks, T/R module substrates, AESA aperture distribution boards |
| Missile Guidance | RF front-end substrates in guidance and seeker systems |
| Phased Array Networks | Commercial phased array antenna circuits at X-band and below |
| Base Station Antennas | Low-loss base station feed networks and LNA boards |
| Satellite Communications | Uplink and downlink passive networks where outgassing matters |
| Digital Radio Systems | DAB and digital radio antenna circuits |
| Passive Microwave | Bandpass filters, hybrid couplers, Wilkinson dividers, LNA matching networks |
| Space Applications | Outgassing-qualified substrates for near-space or satellite hardware |
The missile guidance application is one where DiClad 870’s combination of properties aligns particularly well. Guidance systems require not just low loss for clean signal reception, but also vibration and shock resistance, wide operating temperature range, and long shelf-life stability. DiClad 870 is a soft substrate relative to ceramics, which means it handles shock and vibration loads without cracking. Its 0.02% moisture absorption ensures the Dk doesn’t shift measurably over years of storage. The wide arc resistance (>180 seconds) provides an additional reliability margin in high-voltage-adjacent circuits.
Arlon DiClad 870 PCB Design Considerations
Trace Width and Impedance Calculation
Dk 2.33 produces wider traces for a given impedance on a given substrate thickness compared to higher-Dk materials. For a 50-ohm microstrip on 0.031″ DiClad 870, the trace width is considerably wider than on Rogers RO4003C at the same thickness. This is generally advantageous — wider lines have lower resistive loss and are easier to manufacture within tolerance — but it does require accurate calculation. Always use the correct Dk value in your transmission line calculator. Do not assume Dk 2.33 is a fixed single number across all thicknesses; verify the datasheet value for your specific substrate thickness and order specification.
Dielectric Constant Stability Across Frequency
One of PTFE’s defining advantages is Dk stability across frequency. DiClad 870 maintains a consistent Dk from 1 MHz through well into the millimeter-wave range. This means a design computed at your center frequency will behave predictably across the full operating band without frequency-dependent Dk corrections. For broadband circuit designs — octave-bandwidth amplifiers, wideband limiters, multi-octave filters — this property eliminates a significant category of simulation uncertainty.
Thermal Coefficient of Dk (TCDk) in Temperature-Sensitive Designs
DiClad 870 has a TCDk of -161 ppm/°C across the -10°C to 140°C temperature range at 10 GHz. The negative sign means the Dk decreases as temperature increases — the material becomes electrically “faster” at elevated temperatures. For phased array feed networks where phase consistency must be maintained across a military temperature range, this TCDk will produce a measurable shift in electrical phase length. Include this effect in your thermal-electrical budgeting. If the TCDk of DiClad 870 causes too much phase variation in your specific design, Arlon’s CLTE series (ceramic-filled PTFE with improved TCDk) is worth evaluating as an alternative.
Z-Axis CTE and Via Reliability
With a Z-axis CTE of 217 ppm/°C, DiClad 870 shows a high thermal expansion in the through-board direction — a property shared by all PTFE-based laminates. Copper’s CTE is approximately 17 ppm/°C, so the mismatch between the expanding PTFE dielectric and the copper barrel in a plated through-hole is significant during thermal cycling. To manage this, keep via aspect ratios below 8:1 where possible, specify conservative drill-to-pad ratios for reliable annular ring coverage, and consider blind or buried vias for signal-layer connections in multilayer stackups where the full board thickness does not need to be traversed.
Wider Line Widths and Their Effect on Conductor Loss
An often-underappreciated benefit of DiClad 870’s low Dk is that the wider trace widths required for a given impedance directly reduce resistive conductor loss. At X-band and above, conductor losses in microstrip can dominate over dielectric losses on PTFE-based substrates. A wider trace cross-section lowers the conductor loss per unit length. This is why DiClad 870’s datasheet specifically notes that the stable, low Dk supports wider line widths for lower insertion loss — it’s not just a material property note, it’s a practical circuit performance advantage.
Fabrication Guidelines for Arlon DiClad 870
Material Handling and Storage
Store DiClad 870 panels in a clean, temperature- and humidity-controlled environment. Moisture absorption is very low at 0.02%, but surface contamination from fingerprints, particulates, or chemical exposure will affect plating adhesion and lamination quality. Handle panels with clean gloves and process promptly after removing from protective packaging.
Drilling Requirements
Use fresh carbide drill bits and limit drill stack heights to one or two panels. Worn tooling is the most common cause of PTFE smear in drilled holes. Use appropriate aluminum entry material and backup material to support clean hole entry and breakthrough. Inspect hole walls before proceeding to surface activation and plating.
PTFE Hole Wall Activation — Non-Negotiable
This is the process step that separates fabricators who genuinely know PTFE from those who are guessing. PTFE is chemically inert and will not form a reliable bond with electroless copper without activation. The two standard methods are sodium naphthalate (or sodium ammonia) chemical etching and plasma etch. Both roughen and chemically modify the PTFE hole wall surface to create adhesion sites for the copper deposit. Skipping or under-performing this step produces plated through-holes that pass initial electrical testing but fail under thermal cycling — often dramatically and catastrophically.
Before selecting a fabricator, ask directly: what PTFE activation method do you use, and how do you validate activation quality? If the answer is vague or the fabricator cannot confirm this is a standard step in their process, that is a serious disqualification for DiClad 870 production.
Etching, Assembly, and Soldering
Standard cupric chloride or ammoniacal etchants are fully compatible with DiClad 870’s electrodeposited copper. The copper peel strength of 14 lbs/in provides good support for fine-line etching. DiClad 870 is lead-free process compatible and handles standard SMT reflow profiles without issue. The 0.02% moisture absorption means essentially no moisture is present to outgas and cause solder splash or delamination during reflow. Profile your oven for the actual thermal mass of the board — PTFE laminates conduct heat differently from FR4.
Common Design and Production Pitfalls with Arlon DiClad 870
Confusing DiClad 870 with DiClad 880 in documentation. The two products have similar names and sit adjacent in the DiClad series. DiClad 870 is Dk 2.33, DiClad 880 is Dk 2.17–2.20. Using the wrong Dk in your transmission line calculations from the outset propagates an impedance error through the entire design. Double-check your material call-out on the PCB fabrication drawing against the intended substrate.
Neglecting TCDk in outdoor or wide-temperature designs. At -161 ppm/°C, a 100°C temperature swing shifts the Dk by approximately 0.037. For a tuning-sensitive circuit like a narrowband combline filter at 10 GHz, this drift can produce several MHz of center frequency shift between summer and winter outdoor conditions. Model this into your design simulation with temperature as a swept variable.
Assuming DiClad 870 can be processed exactly like FR4. The PTFE activation step and PTFE-compatible bonding ply selection in multilayer builds are not optional accommodations — they are fundamental requirements. An FR4 fabricator who applies FR4 process parameters to DiClad 870 will produce boards with marginal or failed PTH reliability, even if the boards appear electrically functional off the assembly line.
Not verifying sheet-to-sheet Dk consistency. For precision RF circuits where impedance tolerance is tight, request Dk test data for the specific lot of material being used. Standard production testing covers sampling, not every sheet. If your circuit is sensitive to lot-to-lot Dk variation — as a narrow-bandwidth filter would be — consider specifying individual-sheet test reporting, similar to the LX grade available on CuClad products.
Useful Resources for Arlon DiClad 870 Engineers
| Resource | Description | Link |
| Rogers DiClad 870/880 Product Page | Official Rogers/Arlon product page with property sampling | rogerscorp.com |
| DiClad Series Datasheet (RS Online) | Complete DiClad family datasheet covering all variants | docs.rs-online.com |
| Arlon Microwave & RF Materials Guide | Full DiClad product comparison table with CTE, outgassing, and more | integratedtest.com PDF |
| MatWeb DiClad 870 Entry | Material database entry with all DiClad 870 properties | MatWeb |
| Rogers Laminate Properties Tool | Interactive comparator for all Rogers laminate families | rogerscorp.com tools |
| IPC TM-650 Test Methods | Standard test methods referenced in the DiClad 870 datasheet | ipc.org |
| Arlon Laminate Guide PDF | Arlon laminate technical guide covering PTFE processing | arlonemd.com |
| RayPCB Arlon PCB Resource | Fabrication resource for Arlon high-frequency PCB materials | RayPCB Arlon PCB |
5 Frequently Asked Questions About Arlon DiClad 870
1. What is the main difference between Arlon DiClad 870 and DiClad 880?
Both are PTFE/woven fiberglass laminates from the same Rogers/Arlon family, but they target different points in the loss-versus-stability trade-off. DiClad 870 has a nominal Dk of 2.33 and a Df of 0.0013 at 10 GHz, while DiClad 880 drops to Dk 2.17–2.20 and Df approximately 0.0009 at 10 GHz by using a higher PTFE content. DiClad 870 compensates with better dimensional stability, slightly lower moisture absorption (0.02% vs. DiClad 880’s slightly higher value), and better mechanical handling. For most practical high-frequency applications, DiClad 870’s loss performance is entirely sufficient, and its better processability makes it the more production-friendly choice.
2. Is Arlon DiClad 870 appropriate for space or satellite applications?
Yes. DiClad 870 qualifies for space-adjacent applications based on its NASA outgassing data: Total Mass Loss (TML) of 0.01% and Collected Volatile Condensable Materials (CVCM) of 0.01%. Both values are well within the NASA outgassing threshold typically required for satellite hardware (TML < 1.0%, CVCM < 0.1%). The extremely low moisture absorption of 0.02% also supports long shelf life and stable performance in vacuum environments where absorbed moisture would otherwise outgas and potentially affect nearby optical or sensor surfaces.
3. Can Arlon DiClad 870 be used in multilayer PCB stackups?
Yes. DiClad 870 can be used in multilayer designs, but it requires PTFE-compatible bonding materials — not standard FR4 prepregs. Use Rogers-specified bonding films or PTFE bondply materials designed for high-frequency multilayer construction. The Z-axis CTE of 217 ppm/°C must be considered in via reliability calculations, particularly for through-board vias in applications with wide thermal cycling. Blind and buried via constructions help manage the CTE mismatch by limiting barrel length.
4. What surface finishes are compatible with Arlon DiClad 870?
Standard surface finishes used with PTFE-based PCBs are compatible with DiClad 870. These include ENIG (Electroless Nickel Immersion Gold), immersion silver, immersion tin, and ENEPIG. HASL (Hot Air Solder Leveling) is generally not recommended for PTFE laminates because the high-temperature tin-lead or lead-free solder bath can cause localized thermal damage. For microwave circuits where surface roughness affects conductor loss at higher frequencies, ENIG is often preferred because the controlled gold thickness provides a clean, consistent microstrip surface.
5. How does Arlon DiClad 870 perform at millimeter-wave frequencies above 30 GHz?
PTFE’s inherent Dk stability across frequency means DiClad 870 maintains consistent dielectric properties well into the millimeter-wave range. However, as frequency rises above 20–30 GHz, conductor-dominated loss increasingly outweighs dielectric loss even on an excellent substrate like DiClad 870. At these frequencies, the copper surface roughness becomes the dominant loss mechanism. For mmWave designs on DiClad 870, specify low-profile or rolled annealed copper foil rather than standard electrodeposited copper, and include a copper roughness correction factor in your EM simulation insertion loss predictions. The Df of 0.0013 remains low enough to be a minor contributor to total insertion loss well through Ka-band.
Final Thoughts on Arlon DiClad 870
Arlon DiClad 870 is a material that rewards engineers who take the time to understand what “medium fiberglass/PTFE ratio” actually delivers in practice. The Dk 2.33 and Df 0.0013 at 10 GHz are strong numbers — genuinely competitive with anything in the PTFE laminate category at this Dk level. The 0.02% moisture absorption and qualified NASA outgassing performance extend its usefulness well beyond indoor electronics into outdoor infrastructure, airborne systems, and satellite hardware.
What DiClad 870 asks in return is a fabrication partner who takes PTFE processing seriously: proper hole wall activation, PTFE-compatible bonding materials for multilayer builds, and appropriate drilling parameters. With the right fabricator, these are not difficult requirements. They’re just different from FR4.
For RF and microwave engineers evaluating laminate choices in the Dk 2.2–2.5 range, DiClad 870 should be a standard candidate on any comparison shortlist. In many cases — especially where the design must perform reliably across temperature, humidity, and years of field service — it will be the final answer.
