Arlon IsoClad 917: PTFE Random Glass Fiber Laminate – Specs & Applications

Most engineers who’ve spent time with RF substrates are familiar with the usual dilemma: pick a woven fiberglass PTFE laminate for dimensional stability and dimensional predictability, or go with something softer and less reinforced to squeeze out the last bit of electrical performance. Arlon IsoClad 917 doesn’t fit neatly into that framing because it introduces a third structural option — random, non-woven fiberglass — that changes the trade-off completely. It achieves a Dk of 2.17 or 2.20 and a Df of 0.0013 at 10 GHz, which puts it in the same electrical ballpark as Rogers RT/duroid 5880 and Arlon DiClad 880. What makes IsoClad 917 genuinely different is what the non-woven fiber architecture delivers: true three-dimensional isotropy, the ability to be physically bent into conformal and wrap-around antenna geometries, and Arlon’s proprietary longer-fiber process that provides better dimensional stability and Dk uniformity than other non-woven PTFE laminates in the same class. If you’re designing conformal antennas, radar systems, missile guidance hardware, or any application where the circuit needs to conform to a curved surface or where in-plane electrical isotropy is critical, IsoClad 917 is a material worth understanding thoroughly. This guide covers everything: official specs, complete mechanical data, thickness options, fabrication guidance, full comparisons to competing materials, and five engineer-level FAQs.

What Is Arlon IsoClad 917?

Arlon IsoClad 917 is a non-woven fiberglass-reinforced PTFE composite laminate manufactured for use as a printed circuit board substrate in microwave and RF applications. Unlike the DiClad and CuClad product families — which both use woven fiberglass reinforcement — IsoClad uses randomly oriented, longer glass fibers distributed through the PTFE matrix using a proprietary process. This non-woven, random fiber structure is what sets IsoClad apart structurally from every other Arlon PTFE laminate.

The IsoClad family consists of two products: IsoClad 917 (Dk 2.17 or 2.20) and IsoClad 933 (Dk 2.33). IsoClad 917 sits at the low-Dk, low-loss end of the series — it uses a low ratio of fiberglass to PTFE to achieve the lowest dielectric constant and dissipation factor available in a non-woven fiberglass/PTFE laminate. IsoClad 933 uses more fiberglass for better mechanical rigidity, at the cost of a higher Dk.

IsoClad 917 is manufactured by Arlon EMD, now operating under Elite Material Co. (EMC) of Taiwan following the January 2021 acquisition. The product is also marketed under the Rogers Corporation portfolio following Rogers’ acquisition of Arlon’s microwave laminate line. Specifications and material performance remain consistent with the original Arlon characterization.

The IsoClad 917 product description on the Rogers product page summarizes the key structural benefit precisely: the non-woven reinforcement allows these laminates to be used in applications where the final PCB may be bent in shape, including conformal or wrap-around antennas. No woven glass laminate — DiClad, CuClad, or otherwise — can make that claim. The woven structure locks fiber orientation and prevents bending without fracturing the glass weave. IsoClad 917’s random fiber architecture allows the material to flex without fiber delamination, which opens application categories that are simply inaccessible to conventional rigid RF laminates.

Arlon IsoClad 917 Full Electrical Specifications

All values below are sourced from the official Arlon IsoClad datasheet published by Midwest PCB, tested per IPC and ASTM methods noted. These are the values to use in simulation, impedance stack-up models, and field solvers.

Parameter	Test Method	Condition	IsoClad 917
Dielectric Constant (Dk) @ 10 GHz	IPC TM-650 2.5.5.5	C23/50	2.17 or 2.20
Dissipation Factor (Df) @ 10 GHz	IPC TM-650 2.5.5.5	C23/50	0.0013
Thermal Coefficient of Er (ppm/°C)	IPC TM-650 2.5.5.5 Adapted	–10°C to +140°C	–157
Volume Resistivity (MΩ-cm)	IPC TM-650 2.5.17.1	C96/35/90	1.5 × 10¹⁰
Surface Resistivity (MΩ)	IPC TM-650 2.5.17.1	C96/35/90	1.0 × 10⁹
Arc Resistance (seconds)	ASTM D-495	D48/50	> 180
Dielectric Breakdown (kV)	ASTM D-149	D48/50	> 45
Water Absorption (%)	MIL-S-13949H / IPC TM-650 2.6.2.2	E1/105 + D24/23	0.04
Flammability	UL 94 Vertical Burn / IPC TM-650 2.3.10	C48/23/50, E24/125	UL94-V0

The Df of 0.0013 at 10 GHz is the number that defines where IsoClad 917 sits in the loss landscape. It’s lower than DiClad 870 (Df 0.0013 — actually a match) and DiClad 522/527 (Df 0.0022), and within a factor of 1.4× of the absolute best in its class (DiClad 880 and RT/duroid 5880 at Df 0.0009). For the vast majority of designs operating below 30 GHz, Df 0.0013 is more than adequate to meet insertion loss requirements.

One number worth flagging is water absorption at 0.04%. This is slightly higher than DiClad 880 and DiClad 870 (both 0.02%), which is a consequence of the non-woven fiber structure exposing slightly more surface area. In practice, the 0.04% level is still extremely low — far below the 0.1–0.5% range typical of conventional FR-4 — but it is worth accounting for in outdoor or marine installations and in pre-bake protocols before assembly.

The Dk is stable across frequency. The official IsoClad datasheet includes a Dk vs. frequency plot from 0 to 30 GHz showing less than ±1% variation in Dk across the entire measured range — a characteristic property of PTFE-based materials that thermoset laminates simply don’t replicate. The Df vs. frequency plot similarly shows stable, flat loss tangent behavior from DC to 30 GHz. These stability curves are the practical reason why PTFE substrates simplify wideband and multi-octave designs: you model the circuit at one frequency, and the material doesn’t introduce frequency-dependent corrections that force re-optimization at other bands.

Arlon IsoClad 917 Full Mechanical and Physical Properties

The mechanical data for IsoClad 917 tells the honest story of what the non-woven, low-fiberglass structure delivers — and where its limitations lie.

Parameter	Test Method	Condition	IsoClad 917
CTE — X Axis (ppm/°C)	IPC TM-650 2.4.24 / Mettler TMA	0°C to 100°C	46
CTE — Y Axis (ppm/°C)	IPC TM-650 2.4.24 / Mettler TMA	0°C to 100°C	47
CTE — Z Axis (ppm/°C)	IPC TM-650 2.4.24 / Mettler TMA	0°C to 100°C	236
Tensile Modulus — X/Y (kpsi)	ASTM D-638	A, 23°C	133 / 120
Tensile Strength — X/Y (kpsi)	ASTM D-882	A, 23°C	4.3 / 3.8
Compressive Modulus (kpsi)	ASTM D-695	A, 23°C	182
Flexural Modulus (kpsi)	ASTM D-790	A, 23°C	213
Density (g/cm³)	ASTM D-792 Method A	A, 23°C	2.23
Thermal Conductivity (W/mK)	ASTM E-1225	100°C	0.263
Peel Strength (lbs/in)	IPC TM-650 2.4.8	After Thermal	10

A few figures stand out immediately. The X-axis CTE of 46 ppm/°C and Y-axis CTE of 47 ppm/°C are nearly identical — which is precisely the point. In woven fiberglass laminates, the CTE in the warp and fill directions of the cloth differ because fiber density differs between those directions. With random fibers, the reinforcement is statistically isotropic in the X-Y plane, producing essentially equal CTEs in both directions. For antenna designs where the radiating element dimensions must be thermally stable in both planar directions equally, this isotropy is a genuine performance advantage over woven glass alternatives.

The tensile modulus of 133 kpsi (X-axis) is the lowest in the Arlon PTFE family — significantly softer than DiClad 880 at 267 kpsi, let alone DiClad 522/527 at 706 kpsi. This is the direct mechanical consequence of the low fiberglass content and non-woven structure. IsoClad 917 is the softest, most flexible PCB laminate in the Arlon RF catalog. That flexibility is an intentional design feature when conformal antenna applications are the target. It is a handling challenge when standard rigid PCB fabrication processes are used without modification.

The peel strength of 10 lbs/in is lower than the DiClad family’s typical 14 lbs/in, reflecting the lower fiber content and the inherent low surface energy of PTFE. Proper PTFE surface activation before plating is even more critical with IsoClad 917 than with the more heavily reinforced DiClad materials.

IsoClad 917 NASA Outgassing Data

Parameter	IsoClad 917 Result	NASA Pass Limit
Total Mass Loss (TML)	0.02%	< 1.00%
Collected Volatile Condensable Material (CVCM)	0.00%	< 0.10%
Water Vapor Regain	0.02%	—
Visible Condensate	None	None

IsoClad 917 clears NASA ASTM E595 outgassing requirements with the same comfortable margin as the rest of the Arlon PTFE product line. The inert chemistry of PTFE is what drives these negligible outgassing results, and it holds regardless of the fiber architecture.

The Defining Feature: True 3D Isotropy in Arlon IsoClad 917

The isotropy of Arlon IsoClad 917 is the property that most distinguishes it from every woven fiberglass PTFE laminate on the market, and it deserves a dedicated discussion because it affects design outcomes in ways that aren’t obvious from a datasheet scan.

In a woven glass laminate, the fiberglass plies are aligned in specific directions — warp and fill for standard weaves, or specific rotation angles for cross-plied constructions like CuClad. These directional fiber orientations produce anisotropic electrical and mechanical properties. Dk measured in the X-direction differs slightly from Dk measured in the Y-direction because the effective fiber density differs between those two directions. CTE differs between X and Y for the same reason.

In IsoClad 917, the glass fibers are randomly distributed in all directions. There is no preferred fiber orientation. The result is highly isotropic properties in X, Y, and Z directions — a claim that Arlon explicitly makes in the datasheet. This isotropy has practical consequences in several applications:

Phased Array Antennas: In a phased-array panel where antenna elements are distributed across a large area in both X and Y, any anisotropy in the substrate Dk produces different electrical lengths for traces routed in different directions. Phase errors at individual elements accumulate and degrade beam quality. An isotropic substrate eliminates this source of phase error entirely.

Conformal and Wrap-Around Antennas: When a flat PCB is bent to conform to a curved surface — a missile body, an aircraft fuselage, a vehicle exterior — the bending stress is distributed across the material. Woven glass, with its locked fiber orientations, resists bending and can delaminate or crack under the strain. Random fibers in IsoClad 917 allow the material to accommodate bending without structural failure, making conformal antenna fabrication practical.

Radomes and Low-Loss Dielectric Structures: Applications where the substrate itself is a structural part of the antenna system (radomes, lens elements) benefit from isotropic dielectric properties that present the same Dk to waves arriving from any angle.

Available Thicknesses and Copper Options for IsoClad 917

IsoClad 917 is available in 36″×48″ master sheet size as standard. The material is supplied with copper cladding on both sides. Standard copper options include ½ oz (18 µm), 1 oz (35 µm), and 2 oz (70 µm) electrodeposited copper foil. Rolled copper foil and other weights are available on request. IsoClad is also available bonded to a heavy metal ground plane (aluminum, brass, or copper) that provides integral mechanical support and heat sinking.

Typical Core Thickness	Thickness (mm)	Notes
10 mil	0.254 mm	Thin core stripline use
20 mil	0.508 mm	Common 50-ohm microstrip base
31 mil	0.787 mm	Standard single-layer work
62 mil	1.575 mm	Thicker core applications

When ordering IsoClad products, specify dielectric constant (2.17 or 2.20), thickness, cladding weight, panel size, and any special considerations. Availability of specific Dk/thickness combinations should be confirmed with your distributor — IsoClad 917 is a specialty material and not as widely stocked as DiClad 522/527. Lead times can vary.

IsoClad 917 vs. IsoClad 933: The IsoClad Family Comparison

Understanding where IsoClad 917 sits relative to its family sibling IsoClad 933 is the first question to resolve before specifying either product.

Parameter	IsoClad 917	IsoClad 933
Fiberglass/PTFE Ratio	Low	Higher
Dk @ 10 GHz	2.17 / 2.20	2.33
Df @ 10 GHz	0.0013	0.0016
Thermal Coefficient of Er (ppm/°C)	–157	–132
CTE — X Axis (ppm/°C)	46	31
CTE — Y Axis (ppm/°C)	47	35
CTE — Z Axis (ppm/°C)	236	203
Tensile Modulus X (kpsi)	133	173
Tensile Strength X (kpsi)	4.3	6.8
Compressive Modulus (kpsi)	182	197
Flexural Modulus (kpsi)	213	239
Density (g/cm³)	2.23	2.27
Relative Mechanical Rigidity	Lower	Higher
Best For	Lowest Dk, conformal apps	Better rigidity, mid-Dk

Choose IsoClad 917 when you need the lowest possible Dk (2.17/2.20) and Df (0.0013) in the non-woven PTFE family, or when the design requires conformal bending. Choose IsoClad 933 when the Dk 2.33 is adequate for your impedance requirements and you need better dimensional stability and mechanical robustness from the higher fiberglass content.

Arlon IsoClad 917 vs. Rogers RT/duroid 5880: Direct Comparison

RT/duroid 5880 is the most frequently cited competing product for IsoClad 917, and the comparison is warranted — both are non-woven (random microfiber) PTFE laminates targeting the same low-Dk, low-loss application space.

Parameter	Arlon IsoClad 917	Rogers RT/duroid 5880
Glass Structure	Longer random non-woven fibers	Random glass microfibers
Dk @ 10 GHz	2.17 / 2.20	2.20 (± 0.02)
Df @ 10 GHz	0.0013	0.0009
Water Absorption (%)	0.04	0.02
CTE — X Axis (ppm/°C)	46	31
CTE — Y Axis (ppm/°C)	47	48
Tensile Modulus X (kpsi)	133	~130 (approx.)
Peel Strength (lbs/in)	10	~8–10
Isotropy	Highly isotropic X/Y/Z	Highly isotropic X/Y
Min Thickness Available	10 mil	5 mil (0.127 mm)
Proprietary Fiber Process	Yes (longer fibers, better Dk uniformity)	Standard random microfiber
Global Availability	Less common	Widely stocked

The electrical comparison is close but not identical. RT/duroid 5880 delivers Df 0.0009 vs IsoClad 917’s 0.0013 — that’s a real difference of about 44% in loss tangent, which becomes noticeable in long traces or at high frequencies. If insertion loss is the sole decision criterion, RT/duroid 5880 has the edge.

Where IsoClad 917 claims an advantage is in its proprietary longer-fiber process. Arlon’s datasheet explicitly states that IsoClad products use longer random fibers and a proprietary process to provide greater dimensional stability and better dielectric constant uniformity than competitive non-woven fiberglass/PTFE laminates of similar dielectric constants. This is a direct claim of superiority over RT/duroid 5880-class materials in terms of Dk uniformity across the panel — relevant for large-format arrays where panel-level Dk variation translates to phase errors. Whether this advantage is material in your specific design requires validation with your fabricator using actual lot measurements.

IsoClad 917 vs. Arlon DiClad 880: Woven vs. Non-Woven at the Same Dk

Both IsoClad 917 and DiClad 880 target the Dk 2.17/2.20 range with very similar electrical performance, but they’re structurally different in a fundamental way.

Parameter	Arlon IsoClad 917	Arlon DiClad 880
Glass Structure	Non-woven random fibers	Woven fiberglass
Dk @ 10 GHz	2.17 / 2.20	2.17 / 2.20
Df @ 10 GHz	0.0013	0.0009
CTE — X Axis (ppm/°C)	46	25
CTE — Y Axis (ppm/°C)	47	34
CTE — Z Axis (ppm/°C)	236	252
X-Y Isotropy	True isotropy (46 vs 47)	Anisotropic (25 vs 34)
Tensile Modulus X (kpsi)	133	267
Conformability	Can be bent	Rigid — cannot be bent
Best For	Conformal, isotropic designs	Standard rigid boards needing very low Df

DiClad 880 is the better choice when you need the lowest possible Df (0.0009 vs 0.0013) and dimensional stability in a flat, rigid PCB. IsoClad 917 is the better choice when true X-Y isotropy is required or when the design requires physical bending of the substrate. The X-axis CTE of IsoClad 917 (46 ppm/°C) is significantly higher than DiClad 880 (25 ppm/°C), which means less dimensional stability under temperature — a direct consequence of the lower fiberglass content and non-woven structure. For designs where dimensional stability during thermal cycling is a primary constraint, DiClad 880’s woven glass structure gives it a meaningful advantage.

Key Applications for Arlon IsoClad 917

Conformal and Wrap-Around Antennas

This is the signature application that makes IsoClad 917 unique in the Arlon product line. A conformal antenna is one that conforms to the shape of the structure it’s mounted on — a missile body, an aircraft fuselage, a vehicle roof panel, or a wearable device. These applications require the antenna substrate to be physically bent to match the contour of the host structure. Woven glass PTFE laminates crack or delaminate when bent; IsoClad 917’s random fiber structure accommodates the bend without structural failure. The non-woven reinforcement allows these laminates to be used more easily in applications where the final circuit will be bent to shape.

Radar and Electronic Warfare Systems

Military radar feeds, electronic warfare receivers, and signal intelligence (SIGINT) systems are all cited target applications for IsoClad 917. These programs typically require broad bandwidth, very low insertion loss, and substrate electrical properties that remain stable across wide operating temperature ranges. IsoClad 917’s flat Dk and Df across frequency, combined with NASA-qualified outgassing performance, make it a viable substrate for high-reliability military RF assemblies.

Missile Guidance System PCBs

Guidance system electronics face a combination of demanding requirements: wide temperature range, vibration and shock, high-frequency operation, and the physical constraint that electronics must often conform to the geometry of the missile body. IsoClad 917 addresses the electrical performance and physical conformability requirements simultaneously. It is specifically listed as a target application in the official Arlon IsoClad datasheet.

Stripline and Microstrip RF Circuits

Beyond conformal applications, IsoClad 917 serves as a flat substrate for standard microstrip and stripline designs where the isotropic Dk and very low loss are the primary drivers. Its Dk of 2.17/2.20 produces wider traces than higher-Dk materials for equivalent characteristic impedance, which reduces conductor resistive losses — a useful property in high-power or loss-critical circuits.

Radomes and Dielectric Lens Structures

Applications where the substrate doubles as a structural dielectric in the antenna system — radomes covering phased arrays, dielectric lenses for beam shaping — benefit from IsoClad 917’s true 3D isotropy and low Dk. A Dk that is equal in all spatial directions ensures that electromagnetic waves incident from any angle see the same effective dielectric constant, which is important for maintaining consistent radome transmission properties across the antenna’s scan angle.

PCB Fabrication Considerations for Arlon IsoClad 917

IsoClad 917 shares all the fundamental PTFE processing requirements of the DiClad family, with some additional handling care necessitated by its lower mechanical rigidity.

Panel Handling

With a tensile modulus of just 133 kpsi, IsoClad 917 is the most flexible and easily deformed substrate in the Arlon RF product line. Panels must be handled with care — stored flat, supported fully during transport, and handled with clean gloves to prevent contamination and surface scratching. Even minor surface damage in the active circuit area can affect impedance uniformity in microstrip structures.

Drilling

Standard PTFE drilling protocols apply: sharp, new carbide bits; reduced feed rate and spindle speed compared to FR-4; entry and exit backup material; and significantly reduced hit count per bit relative to FR-4 parameters. The softness of IsoClad 917 makes it more susceptible to drill bit smearing than the more rigid DiClad laminates. Fresh bits are not optional — they make a measurable difference in hole wall quality and plated via reliability.

PTFE Surface Activation

The non-woven PTFE surface of IsoClad 917 is chemically inert and will not bond to electroless copper without surface activation. Sodium naphthalene etching or plasma etching is required before metallization. Peel strength of 10 lbs/in (after thermal) underscores the importance of proper activation — inadequate treatment will result in pad lifting and via delamination that typically emerge during thermal cycling. Confirm your fabricator’s documented and validated activation process before committing your design to a new shop.

Impedance Control and Dk Selection

IsoClad 917 is available in Dk 2.17 and Dk 2.20. Always request the actual measured Dk certificate for your specific material lot and use that value in your field solver. As with all PTFE laminates, request low-profile or rolled copper foil if your design operates above 15 GHz to reduce conductor roughness losses at frequencies where skin depth becomes comparable to foil surface roughness.

Conformal Bending Process

For applications where IsoClad 917 is being bent into a conformal shape, bending should be performed after etching but before component assembly. Bend radius should be confirmed with your fabricator — there is a minimum bend radius below which even IsoClad 917 will crack or delaminate. Bending over a mandrel to control radius uniformity is standard practice for conformal antenna fabrication.

For full fabrication support with IsoClad 917, including conformal bending guidance, PTFE process validation, and stack-up design consultation, working with an experienced Arlon PCB specialist is the practical first step before committing your design to production.

Full Arlon PTFE Family Comparison: Where IsoClad 917 Fits

Parameter	DiClad 522/527	DiClad 870	DiClad 880	IsoClad 917	IsoClad 933
Glass Structure	Woven	Woven	Woven	Non-woven	Non-woven
Dk @ 10 GHz	2.40–2.65	2.33	2.17/2.20	2.17/2.20	2.33
Df @ 10 GHz	0.0022	0.0013	0.0009	0.0013	0.0016
CTE — X/Y (ppm/°C)	14 / 21	17 / 29	25 / 34	46 / 47	31 / 35
Tensile Modulus X (kpsi)	706	485	267	133	173
X-Y Isotropy	Anisotropic	Anisotropic	Anisotropic	Isotropic	Isotropic
Conformable	No	No	No	Yes	Limited
Relative Rigidity	Highest	Moderate	Low	Lowest	Low

This table makes the unique value of IsoClad 917 visible immediately: it is the only Arlon RF laminate in the Dk 2.17/2.20 range that delivers true in-plane isotropy and conformability. If either of those properties matters to your design, IsoClad 917 is the answer. If neither matters and you need the lowest Df at that Dk range, DiClad 880 is stronger on the Df metric.

Useful Resources for Engineers Working With Arlon IsoClad 917

Resource	Description	Link
Official Arlon IsoClad Datasheet (PDF)	Full IsoClad 917 and 933 spec table including all electrical, mechanical, and outgassing data	midwestpcb.com (PDF)
Rogers IsoClad 917 Product Page	Official Rogers/Arlon product page with Laminate Properties Tool access	rogerscorp.com
MatWeb IsoClad 917 Material Entry	Searchable material property database entry for IsoClad 917	matweb.com
LookPolymers IsoClad 917 Entry	Aggregated property overview for Arlon IsoClad 917	lookpolymers.com
Hughes Circuits IsoClad Materials Guide	Fabricator overview of IsoClad 917 and 933 with application context	hughescircuits.com
Arlon RF & Microwave Materials Guide (PDF)	Full Arlon product line guide including IsoClad, DiClad, CuClad, CLTE, and AD series	integratedtest.com (PDF)
Arlon EMD Official Website	Manufacturer’s official documentation portal for all Arlon laminates	arlonemd.com
RF Global Net IsoClad Overview	Technical overview of IsoClad applications and features with datasheet download link	rfglobalnet.com

Frequently Asked Questions About Arlon IsoClad 917

1. Can Arlon IsoClad 917 actually be bent, and what is the minimum bend radius?

Yes — the non-woven fiber structure of IsoClad 917 allows the material to be physically bent into conformal shapes without the fiber delamination or cracking that would occur in a woven glass laminate like DiClad or CuClad. The minimum bend radius is not published as a universal specification because it depends on core thickness — thinner cores tolerate tighter radii than thicker ones. In practice, for a 31 mil (0.787 mm) core, a bend radius of approximately 25–50mm is achievable without delamination, though this should be validated with your fabricator for your specific thickness and copper weight. Bending is performed on the etched panel before component assembly, over a controlled mandrel. Consult your fabricator early if conformal bending is part of your manufacturing process — it requires specific tooling and process documentation.

2. How does IsoClad 917 compare to Taconic TP-2 or similar non-woven PTFE laminates?

Taconic TP-2 is a non-woven (random glass microfiber) PTFE laminate with comparable Dk (2.10–2.17) and Df (~0.0009–0.0012) to IsoClad 917. The key claim in the Arlon IsoClad specification is that IsoClad products use longer random fibers and a proprietary process to deliver better dimensional stability and Dk uniformity than competitive non-woven fiberglass/PTFE laminates of similar dielectric constants. This is a direct competitive claim targeting products like Taconic TP-2 and RT/duroid 5880. In material evaluations for large-format panels, requesting Dk uniformity measurements across the panel area from actual material lots is the best way to validate this claim for your specific application.

3. Is IsoClad 917 suitable for multilayer PCB constructions?

Yes, IsoClad 917 can be used as cores in multilayer RF constructions. Compatible PTFE-based bonding plies are required — standard FR-4 prepreg is not compatible with PTFE lamination cycles and bonding chemistry. The lower mechanical rigidity (tensile modulus 133 kpsi) compared to DiClad laminates means that multilayer stackups using IsoClad 917 cores need to be designed with appropriate mechanical support — thin IsoClad 917 multilayers can be more prone to board warpage than stiffer woven-glass equivalents. Work with a fabricator experienced in PTFE multilayer constructions to define appropriate stackup constraints and lamination parameters for your specific build.

4. What is the difference between IsoClad 917 and CuClad 217 from Arlon?

Both IsoClad 917 and CuClad 217 target the Dk 2.17/2.20 range, but they are structurally different. CuClad 217 is a woven fiberglass/PTFE laminate with cross-plied (alternating 90°) ply orientation, providing true electrical and mechanical isotropy in the XY plane — a feature Arlon describes as unique to CuClad. IsoClad 917 achieves XY isotropy through random fiber distribution rather than cross-plied woven construction. CuClad 217’s woven structure makes it more dimensionally stable and mechanically rigid than IsoClad 917. IsoClad 917’s non-woven structure makes it conformable — bendable — which CuClad 217 is not. For flat rigid PCB applications where XY isotropy is needed, CuClad 217 offers better mechanical stability. For conformal or wrap-around antenna applications, IsoClad 917 is the correct choice.

5. Does IsoClad 917 require any special storage or handling compared to standard DiClad laminates?

The storage requirements are similar — cool, dry conditions away from direct sunlight, stored flat to prevent warpage — but the handling precautions are more demanding due to IsoClad 917’s lower mechanical rigidity. The tensile modulus of 133 kpsi (about half of DiClad 880, and one-fifth of DiClad 522) means panels flex and deform more easily under their own weight when handled unsupported. Always support panels across their full width when moving them; never grip them at a corner or edge only. Surface contamination (skin oils, particulates) affects PTFE surface activation quality during plating, so clean glove handling is mandatory. For long-term storage, keeping panels interleaved with clean cardboard or separator sheets prevents surface damage and contamination.

Conclusion

Arlon IsoClad 917 is a specialized substrate for a specific class of design challenges — the ones where true X-Y-Z isotropy and/or physical conformability are genuine requirements, not simply nice-to-have features. Its Dk of 2.17/2.20 and Df of 0.0013 at 10 GHz deliver genuine low-loss performance in the same application space as Rogers RT/duroid 5880 and Arlon DiClad 880. What separates IsoClad 917 from both of those materials is what its non-woven random fiber structure uniquely enables: the ability to bend the finished circuit into a conformal shape for wrap-around antenna fabrication, and the true three-dimensional isotropy that eliminates directional Dk variation in both flat-panel phased arrays and radome structures.

For applications that don’t need conformability or 3D isotropy, DiClad 880 offers better Df (0.0009) with higher mechanical rigidity, and RT/duroid 5880 is more widely stocked with an equally strong electrical specification. But for conformal antennas, missile-body electronics, wrap-around radar elements, and any phased array application where true X-Y Dk isotropy is a hard requirement, Arlon IsoClad 917 is the material the application is asking for.

For sourcing, conformal fabrication support, and expert guidance on IsoClad 917 stack-ups and processing requirements, working with an experienced Arlon PCB manufacturer ensures your material selection translates correctly into a manufacturable design.