Complete engineering guide to Arlon DiClad 527 — electrical and mechanical specs, DiClad 527 vs 522 comparison, fabrication requirements, NASA outgassing data, and application guide for RF and microwave PCB designers.

There’s a recurring dilemma in microwave PCB design that most RF engineers know well: you need low loss for your circuit to perform, but you also need a substrate that doesn’t fight you at every step of the fabrication process. Very high-PTFE-content laminates like DiClad 880 or CuClad 217 offer exceptional electrical properties, but they’re soft, dimensionally tricky, and require fabricators who know exactly what they’re doing. On the other side, standard thermoset materials like RO4003 are far easier to process but can’t match the loss performance of PTFE at higher frequencies.

Arlon DiClad 527 occupies a deliberate middle position in this landscape. It’s a woven fiberglass reinforced, PTFE-based composite laminate that prioritizes dimensional stability and mechanical robustness without abandoning the low-loss credentials that make PTFE materials worth the trouble. Understanding where DiClad 527 fits, what it delivers, and how to design and fabricate with it is what this guide is for.

What Is Arlon DiClad 527?

Arlon DiClad 527 is a woven fiberglass reinforced PTFE-based composite material designed for use as a printed circuit board substrate in high-frequency and microwave applications. It belongs to the DiClad product family originally developed by Arlon Materials for Electronics — now part of Rogers Corporation following Rogers’ acquisition of Arlon LLC.

The defining design principle behind DiClad 527 is its high fiberglass-to-PTFE ratio. This ratio is precisely controlled to push the material toward greater dimensional stability, better registration, and mechanical behavior that approaches conventional PCB substrates, while still maintaining the low loss properties inherent to PTFE-based systems. The Dk range of 2.40 to 2.65 reflects this compromise: slightly higher than the ultra-pure PTFE end of the spectrum (Dk ~2.1), but significantly lower than any thermoset or ceramic-filled material.

An important distinction to understand about DiClad 527 compared to its CuClad counterparts is ply orientation. The coated fiberglass plies in DiClad materials are aligned in the same direction — this is parallel-plied construction, not cross-plied. If your application requires true X-Y isotropy (as some phased array antenna designs do), you’d need to look at the CuClad family instead. But for the majority of filter, coupler, LNA, and power divider applications where single-direction dimensional stability is the priority, parallel-plied DiClad 527 is often the better practical choice.

For engineers looking at the full spectrum of Arlon PCB materials, DiClad 527 represents the high-stability end of the DiClad series for the 2.4–2.65 Dk range.

Arlon DiClad 527 Key Specifications

The table below presents the typical electrical and mechanical properties for Arlon DiClad 527. These are typical values and should not be used as specification limits. Always verify against the current Rogers/Arlon datasheet for your specific thickness and application.

Property	Value	Test Method
Dielectric Constant (Dk) @ 10 GHz	2.40 – 2.65	IPC TM-650 2.5.5.5
Dissipation Factor (Df) @ 10 GHz	0.0018	IPC TM-650 2.5.5.5
Dielectric Constant @ 1 MHz	2.40 – 2.65	IPC TM-650 2.5.5.3
Thermal Coefficient of Er (TCDk)	-153 ppm/°C	IPC TM-650 2.5.5.7
CTE (X-axis)	~14 ppm/°C	IPC TM-650 2.4.41
CTE (Y-axis)	~21 ppm/°C	IPC TM-650 2.4.41
CTE (Z-axis)	~173 ppm/°C	IPC TM-650 2.4.41
Tensile Modulus	706 kpsi	ASTM D882
Water Absorption	0.03%	IPC TM-650 2.6.2
Specific Gravity	2.31 g/cm³	ASTM D792
Thermal Conductivity	~0.254 W/m·K	ASTM E1461
UL Flammability Rating	UL94-V0	UL94
NASA Outgassing (TML)	0.02%	NASA SP-R-0022A
NASA Outgassing (CVCM)	0.00%	NASA SP-R-0022A
Typical Peel Strength (1 oz Cu)	≥ 14 lbs	IPC TM-650 2.4.8

Two numbers in that table deserve special attention. The water absorption of just 0.03% is remarkably low — even by PTFE standards — and it has real-world consequences in base station antenna and outdoor radar applications where long-term moisture stability is critical. The NASA outgassing data (essentially zero CVCM) also explains why DiClad 527 shows up in satellite and space-adjacent programs where outgassing is a qualification constraint.

Available Thickness and Dk Options for Arlon DiClad 527

One of DiClad 527’s practical advantages is its wide range of available thicknesses, starting from very thin substrates that are useful in compact multilayer RF stackups. The table below summarizes standard configurations from the Arlon/Rogers materials guide.

Thickness (inches)	Thickness (mm)	Available Dk Options
0.005″	0.127	2.50, 2.55
0.010″	0.254	2.45, 2.50, 2.55, 2.60
0.015″	0.381	2.45, 2.50, 2.55
0.020″	0.508	2.45, 2.50, 2.55, 2.60
0.031″	0.787	2.45, 2.50, 2.55, 2.60
0.047″	1.194	2.50, 2.55, 2.60
0.062″	1.575	2.45, 2.50, 2.55, 2.60
0.125″	3.175	2.50, 2.55, 2.60

Master sheet sizes are available in 36″ × 72″, 36″ × 48″, and 36″ × 36″. The range of available sheet sizes, combined with the wide thickness offering, makes DiClad 527 well suited for multi-circuit panel layouts and moderate-to-high volume production runs.

Copper cladding is available in ½ oz, 1 oz, and 2 oz electrodeposited (ED) copper. For fine-line or millimeter-wave designs where conductor surface roughness becomes a dominant loss mechanism, rolled annealed (RA) copper may be available on request and is worth specifying.

Understanding the DiClad 527 Fiberglass-to-PTFE Ratio Design Philosophy

To design well with DiClad 527, it helps to understand what the high fiberglass-to-PTFE ratio actually buys you — and what it costs you.

Pure or near-pure PTFE laminates like DiClad 880 deliver the lowest possible loss (Df approaching 0.0009 at 10 GHz) and the lowest Dk (~2.17), but the high PTFE content makes the material soft and dimensionally challenging. Etching-induced dimensional change is larger, registration in multilayer builds is harder to control, and the boards require more care in handling during fabrication. For a one- or two-layer prototype in a research lab, this is manageable. For a high-volume production run of base station antenna boards, it’s a real manufacturing risk.

DiClad 527 adds significantly more fiberglass reinforcement compared to DiClad 880 or DiClad 870. DiClad 522 and DiClad 527 use a higher fiberglass/PTFE ratio to provide mechanical properties approaching conventional substrates. Other advantages include better dimensional stability and lower thermal expansion in all directions. The tradeoff is a Df of 0.0018 at 10 GHz rather than 0.0009 — roughly double the dielectric loss. For most base station antenna, radar feed network, and LNA applications, 0.0018 is still excellent performance, and the dimensional stability benefits are very much worth it.

The consistency and control of the PTFE-coated fiberglass cloth is the other key quality attribute. The woven fiberglass reinforcement in DiClad products provides greater dimensional stability than nonwoven fiberglass reinforced PTFE based laminates of similar dielectric constants. The consistency and control of the PTFE coated fiberglass cloth allows Arlon to offer a greater variety of dielectric constants and produces a laminate with better dielectric constant uniformity than comparable non-woven fiberglass reinforced laminates. Dk uniformity within a panel is not just a comfort specification — it directly affects the yield of tuning-sensitive circuits like bandpass filters and branch-line hybrids.

Arlon DiClad 527 vs. DiClad 522: Key Differences

DiClad 527 is frequently paired with DiClad 522 in documentation, and engineers new to the DiClad family often ask what distinguishes them. Both share the same Dk range (2.40–2.65) and application profile, but they are distinct products used in complementary ways.

Parameter	DiClad 522	DiClad 527
Dk Range @ 10 GHz	2.40 – 2.60	2.40 – 2.65
Dissipation Factor @ 10 GHz	0.0018	0.0018
Thinnest Available	0.015″	0.005″
Thickest Available	0.250″	0.125″
Best Fit	Thicker single-layer boards, power circuits	Thin RF circuits, multilayer builds
Ply Orientation	Parallel-plied	Parallel-plied
Water Absorption	0.03%	0.03%

The most practical difference between the two is the thickness range. DiClad 527 goes down to 0.005″ (0.127 mm), making it the right choice when you need a thin dielectric for compact impedance-controlled lines or when you’re building a multilayer stackup with thin RF signal layers. DiClad 522 covers the thicker range and goes up to 0.250″, which is advantageous for substrates that double as structural elements in outdoor antenna housings or power amplifier boards.

In many multilayer designs combining DiClad materials, DiClad 527 provides the thin inner signal layers while DiClad 522 serves as a thicker core or outer layer. Both are processed using the same PTFE-based fabrication approach.

Arlon DiClad 527 Compared to Other High-Frequency Laminates

Choosing between DiClad 527 and competitive or sibling materials comes down to understanding the performance and processability trade-offs in your specific application.

Material	Nominal Dk	Df @ 10 GHz	Mechanical Stability	Best Application
Arlon DiClad 880	2.17 – 2.20	~0.0009	Lower	Lowest loss priority
Arlon DiClad 870	2.33	~0.0013	Medium	Balanced Dk/loss
Arlon DiClad 527	2.40 – 2.65	0.0018	High	Stable production, base station
Rogers RT/duroid 5880	2.20	0.0009	Lower	Lowest loss, lab/defense
Rogers RO4003C	3.55	0.0027	Very High	Thermoset, volume production
Standard FR4	4.2 – 4.5	>0.020	Very High	Not suitable for microwave

DiClad 527 delivers a loss performance that is roughly 3× better than RO4003C at 10 GHz, while offering mechanical stability that is considerably better than RT/duroid 5880 or DiClad 880. For applications where the antenna gain budget or filter insertion loss specification is tight but where production volumes and fabrication yield also matter, DiClad 527 hits a genuinely useful operating point that neither the ultra-low-loss nor the thermoset materials can match.

Typical RF and Microwave Applications for Arlon DiClad 527

The application set for DiClad 527 is well defined by its combination of low loss, excellent dimensional stability, very low moisture absorption, and favorable outgassing behavior.

Application Category	Specific Use Cases
Military & Defense	Radar feed networks, missile guidance RF circuits, electronic warfare receive chains
Phased Array Systems	Commercial phased array antenna feed networks (radar, comms, AESA)
Cellular Infrastructure	Low-loss base station antenna feed networks, tower-top LNA boards
Satellite & Space	Uplink/downlink microwave circuits where outgassing is a constraint
Digital Radio & Broadcasting	DAB, satellite radio antenna circuits and combiners
Passive RF Components	Filters, directional couplers, power dividers, hybrid couplers, LNAs

The low moisture absorption of 0.03% deserves emphasis in the base station context. Outdoor antenna systems experience temperature cycling, condensation, and long-term humidity exposure. A substrate that absorbs moisture changes its Dk, which shifts the resonant frequency of antenna elements and the center frequency of filters. DiClad 527’s near-zero moisture absorption gives antenna designers confidence that the RF performance they characterize in the lab will be maintained across years of field deployment.

The NASA outgassing data (TML 0.02%, CVCM 0.00%) is equally significant for satellite and space-adjacent applications. Outgassing in vacuum can contaminate optical surfaces and sensitive detector materials. DiClad 527 meets the threshold that satellite programs typically impose.

PCB Design Considerations for Arlon DiClad 527

Impedance Control and Trace Width Calculation

A Dk range of 2.40–2.65 rather than a single fixed value is the most important design consideration for trace width calculation. Unlike a thermoset material with a tight, fixed Dk, DiClad 527’s Dk depends on the specific Dk option ordered and the actual fabricated laminate thickness. Always use the actual Dk value for the specific sub-grade you are ordering (e.g., 2.50, 2.55, or 2.60) rather than a midpoint assumption.

For a 50-ohm microstrip on DiClad 527 at Dk 2.55 and 0.031″ substrate thickness, the required trace width will be significantly different from the same circuit on FR4. Use an accurate electromagnetic field solver or a validated transmission line calculator with the correct Dk and substrate thickness. Do not copy trace widths from FR4 designs.

Dk Stability Across Frequency

One of the well-known advantages of PTFE-based materials is how stable the dielectric constant is across frequency. DiClad 527, like all DiClad and CuClad materials, maintains essentially flat Dk from 1 MHz through the microwave range. This simplifies wideband circuit design — you don’t need to apply frequency-dependent Dk corrections to your simulation, and the impedance behavior you compute at your center frequency is representative of the full operating band.

Managing TCDk in Temperature-Sensitive Designs

DiClad 527 has a thermal coefficient of Er (TCDk) of approximately -153 ppm/°C. This means the dielectric constant decreases as temperature increases. For precision phase-matching applications — phased array feed networks where beam pointing accuracy depends on consistent electrical phase — this temperature-induced Dk shift can produce measurable beam squint at temperature extremes. Budget the TCDk into your system-level analysis for any phase-sensitive application.

Z-Axis CTE and Via Reliability

At approximately 173 ppm/°C in the Z-axis, DiClad 527’s Z-axis CTE is much higher than copper (~17 ppm/°C). This CTE mismatch drives barrel fatigue in plated through-holes during thermal cycling. For multilayer DiClad 527 boards used in environments with wide temperature swings — outdoor base station electronics, airborne radar systems — keep via aspect ratios low (ideally below 8:1), avoid excessively long barrel lengths, and consider the use of micro-via or blind via constructions for signal layers where possible.

Fabrication Guidelines for Arlon DiClad 527

Processing DiClad 527 is a different discipline from FR4 fabrication. The material’s PTFE base brings several process-specific requirements that must be followed to achieve reliable, high-yield boards.

Cutting and Panel Preparation

DiClad 527’s higher fiberglass content compared to DiClad 880 makes it somewhat more forgiving to cut and shear than ultra-soft PTFE laminates, but it is still a PTFE composite. Use sharp tooling and maintain clean cutting surfaces. Store panels in a controlled environment — temperature- and humidity-stable — and process them promptly after unpacking to minimize surface contamination that can affect subsequent processing steps.

Drilling

Drill at low stack heights — one to two panels maximum per stack. Use carbide drill bits with sharp cutting edges, and use appropriate entry and exit materials to support clean hole walls at entry and break-through. Inspect drilled hole walls before plating. PTFE smear inside holes — caused by heat buildup from dull tooling or excessive feed rates — is a leading cause of plated through-hole reliability failure in PTFE-based laminates.

PTFE Hole Wall Activation

This is the most critical process step unique to PTFE laminates. PTFE is chemically inert and will not bond to electroless copper without surface activation. Before electroless copper deposition, every hole wall must be treated with either a sodium naphthalate chemical etch or a plasma etch process to roughen and activate the PTFE surface. Skipping or under-performing this step causes plated through-holes that appear acceptable visually but fail under thermal cycling due to poor adhesion between the PTFE surface and the copper deposit.

Confirm with your fabricator specifically which PTFE activation process they use and how they validate it. This should be a standard qualification question, not an afterthought.

Etching and Copper Processing

Standard cupric chloride or ammoniacal etchants are compatible with DiClad 527’s electrodeposited copper foils. Peel strength for 1 oz copper on DiClad 527 is typically above 14 lbs/inch, which is good for fine-line processing. Handle etched panels carefully — while DiClad 527 is more mechanically robust than DiClad 880, it is still more susceptible to edge damage than a thermoset laminate.

Multilayer Lamination

Bonding DiClad 527 cores into multilayer structures requires PTFE-compatible bonding plies. Standard FR4 prepregs are not appropriate. Use Rogers-specified bonding films or PTFE-based bonding plies designed for high-frequency multilayer construction. Follow the bonding film supplier’s recommended temperature and pressure profiles precisely — deviations lead to non-uniform bond line thickness, which directly causes impedance variation across the panel.

Assembly and Soldering

DiClad 527 is lead-free process compatible and conforms to IEC 61249-2-21. Standard SMT reflow profiles are compatible with the material. The low water absorption of 0.03% means there is virtually no risk of moisture-induced delamination or solder splashing during reflow. Profile your oven based on the actual thermal behavior of the populated board — PTFE laminates distribute heat differently from FR4 due to lower thermal conductivity.

Common Pitfalls When Working with Arlon DiClad 527

Specifying an incorrect Dk for trace width calculation. DiClad 527 is available in multiple Dk sub-grades (2.45, 2.50, 2.55, 2.60, 2.65). Using a generic “2.5” value when your actual ordered material is 2.60 introduces an impedance error that accumulates across all transmission lines in the design. Confirm the exact Dk specification at the time of ordering and use that value in your models.

Applying parallel-plied dimensions to a cross-plied assumption. DiClad 527 uses parallel-plied construction — all fiberglass plies run in the same direction. The material is not isotropic in the X-Y plane. This is generally not a problem for most microwave circuit topologies, but if your design relies on equal electrical behavior in orthogonal orientations (certain balanced antenna designs, for example), DiClad 527 is the wrong material choice. Use CuClad 250 instead for cross-plied construction at a similar Dk.

Not qualifying the PTFE activation step. The sodium etchant or plasma activation step before electroless copper is not optional. Fabricators who primarily process thermoset materials may not have this step in their standard process flow. Verify it explicitly before awarding a job.

Ignoring moisture effects on long-term field deployment. DiClad 527’s 0.03% water absorption is excellent, but it is not zero. For very long service life outdoor antenna applications (15+ years), understand the encapsulation and sealing of the final assembly and verify that the board is not exposed to prolonged standing water.

Useful Resources for Arlon DiClad 527 Engineers

Resource	Description	Link
Rogers DiClad 527 Product Page	Official Rogers/Arlon product page with data sampling	rogerscorp.com
Arlon Microwave & RF Materials Guide	Full DiClad series comparison tables and specifications	integratedtest.com PDF
DiClad Series Datasheet (RS Online)	DiClad 880, 870, 522, 527 full property tables	docs.rs-online.com
MatWeb DiClad 522/527 Entry	Material property database with unit conversions	MatWeb
LookPolymers DiClad 527 Entry	Material summary with typical applications	lookpolymers.com
Rogers Laminate Properties Tool	Interactive sorting and comparison of Rogers laminate properties	rogerscorp.com tools
IPC TM-650 Test Methods	Standard test methods referenced in the DiClad 527 datasheet	ipc.org
RayPCB Arlon PCB Guide	Fabrication guidance for Arlon PCB material families	RayPCB Arlon PCB

5 Frequently Asked Questions About Arlon DiClad 527

1. What is the difference between Arlon DiClad 527 and Rogers RT/duroid 5880?

Both are woven fiberglass reinforced PTFE laminates, but they serve different performance priorities. RT/duroid 5880 has a Dk of 2.20 and a Df of 0.0009 at 10 GHz — lower than DiClad 527’s 0.0018 — making it the choice when insertion loss is the dominant constraint. DiClad 527 compensates with significantly better dimensional stability, better registration, and more predictable behavior in volume production. For military radar and commercial base station antenna programs where production yield and consistency matter alongside loss performance, DiClad 527 is often the more practical choice.

2. Can Arlon DiClad 527 be used for multilayer PCB construction?

Yes, but it requires compatible PTFE-based bonding plies rather than standard FR4 prepregs. The bonding materials must be selected to match the CTE and processing temperature requirements of PTFE-based laminates. DiClad 527’s availability down to 0.005″ makes it well suited as thin signal layers in multilayer RF stackups. Consult Rogers/Arlon’s multilayer design guide and confirm your fabricator’s multilayer PTFE process before designing the stackup.

3. Is DiClad 527 a good choice for base station antenna applications?

It is one of the strongest choices in this category. The combination of Df 0.0018 at 10 GHz, water absorption of only 0.03%, UL94-V0 flammability rating, and very low TCDk makes it well suited for outdoor antenna environments where long-term electrical stability under temperature and moisture cycling is required. The excellent dimensional stability also supports multi-circuit panel processing in the high volumes typical of base station antenna production.

4. Does Arlon DiClad 527 require special etching or activation before plating?

Yes. Like all PTFE-based laminates, DiClad 527 requires hole wall activation before electroless copper deposition. The standard approach is sodium naphthalate chemical treatment or plasma etch. This step oxidizes and roughens the PTFE surface to create mechanical adhesion sites for the copper deposit. Without it, the plated through-holes will appear visually acceptable but will fail under thermal cycling due to adhesion failure at the PTFE-copper interface.

5. How do I choose between DiClad 527 and DiClad 522 for my design?

The primary selection criterion is substrate thickness. If your design requires dielectrics thinner than 0.015″ — common in compact multilayer RF stackups — DiClad 527 is the only option, as it is available down to 0.005″. For thicker substrates in the 0.031″ to 0.250″ range, both materials are available, and the choice comes down to panel size availability and your specific Dk requirement. Both share the same electrical properties (Dk 2.40–2.65, Df 0.0018), so there is no electrical performance reason to prefer one over the other when both thickness options exist for your target dimension.

Final Thoughts on Arlon DiClad 527

Arlon DiClad 527 is a mature, well-characterized material that has earned its place in high-performance RF and microwave PCB design by solving a practical problem: how do you get genuinely low-loss PTFE performance in a substrate that behaves predictably in real production environments?

The answer DiClad 527 gives is a deliberately elevated fiberglass-to-PTFE ratio that improves dimensional stability and registration without pushing the dissipation factor beyond what most base station, radar, and phased array applications can tolerate. The near-zero moisture absorption and excellent NASA outgassing performance extend that reliability into outdoor and space-adjacent deployments.

For any new design in the 2.4–2.65 Dk range where production consistency, long-term stability, and PTFE-class loss performance all matter, DiClad 527 deserves to be the first material on your shortlist — not an afterthought. Just make sure your fabricator has genuine PTFE processing capability and can confirm their hole wall activation process before you commit to a stackup.