Arlon CuClad 233 PCB Laminate: Datasheet, Specs & RF Applications

There’s a pattern most RF engineers follow when they’re specifying a substrate for the first time: they either reach for the highest-performance material they can justify (which often means CuClad 217) or they grab a familiar ceramic-filled hydrocarbon laminate. What gets overlooked surprisingly often is Arlon CuClad 233 — the material that actually sits in the practical sweet spot for a large proportion of microwave PCB designs.

CuClad 233 isn’t trying to win a spec sheet competition. It delivers a Dk of 2.33 and a dissipation factor of 0.0013 at 10 GHz — not the absolute lowest numbers available in its class, but combined with meaningfully better dimensional stability and mechanical robustness than CuClad 217, it represents a different engineering compromise. And for filters, couplers, power dividers, and phased array antennas that need both low loss and consistent manufacturing yield, that compromise looks very sensible.

This guide covers the complete technical picture for Arlon CuClad 233: what it is, what the numbers actually mean for your design, how to fab it without issues, and where it fits in the RF laminate landscape.

What Is Arlon CuClad 233?

Arlon CuClad 233 is a cross-plied, woven fiberglass-reinforced PTFE (polytetrafluoroethylene) laminate designed specifically for microwave and RF printed circuit board applications. Originally developed and manufactured by Arlon Materials for Electronics (MED), the CuClad product line is now owned and produced by Rogers Corporation following Rogers’ acquisition of Arlon’s electronics materials business. The product continues to be specified by both trade names — “Arlon CuClad 233” and “Rogers CuClad 233” — in engineering documentation, material databases, and supply chains.

The designation “233” directly represents its nominal dielectric constant: Er = 2.33. This places it in the middle of the CuClad series, which spans from Er 2.17 (CuClad 217, maximum PTFE content for lowest possible loss) through to Er 2.40–2.60 (CuClad 250, maximum glass content for mechanical stability). CuClad 233 uses a medium fiberglass-to-PTFE ratio, deliberately calibrated to balance low dielectric constant and dissipation factor without giving up the mechanical robustness that engineers need when a board has to survive assembly, mounting, and field use.

The construction is cross-plied — alternating layers of PTFE-coated fiberglass cloth are oriented at 90° to each other through the laminate stack. This is not incidental; it’s the structural decision that gives CuClad 233 its claim to true XY-plane electrical and mechanical isotropy, a property that no other woven or non-woven fiberglass PTFE laminate can replicate. For a broader look at the Arlon PCB material family and how CuClad 233 fits across the full portfolio, that context is worth understanding when you’re comparing across multiple substrate candidates.

Arlon CuClad 233 Full Datasheet and Specifications

The numbers below are sourced from the official Rogers/Arlon CuClad series datasheet. These are typical properties — as the datasheet explicitly states, they should not be used as specification limits in procurement documents. For application-critical procurement, use the Rogers Laminate Properties Tool for confirmed test data, or specify the “LX” grade to receive individual piece test reports.

Electrical Properties

Parameter	Value	Test Method / Condition
Dielectric Constant (Dk) at 1 MHz	2.33	IPC TM-650 2.5.5.3, C23/50
Dielectric Constant (Dk) at 10 GHz	2.33	IPC TM-650 2.5.5.5C
Dissipation Factor (Df / tan δ) at 10 GHz	0.0013	IPC TM-650 2.5.5.5C
Dk Stability vs. Frequency	Very high (flat from 1 MHz to 20+ GHz)	—
Volume Resistivity	8.0 × 10⁸ MΩ·cm	IPC TM-650 2.5.17.1
Surface Resistivity	2.4 × 10⁶ MΩ	IPC TM-650 2.5.17.1
Dielectric Breakdown Voltage	>180 V/mil	IPC TM-650 2.5.6.2

Physical and Mechanical Properties

Parameter	Value	Test Method
Density	2.26 g/cc (0.0817 lb/in³)	ASTM D792 Method A
Water Absorption	0.02%	IPC TM-650 2.6.2.2
Tensile Strength (MD / CMD)	510 / 414 psi	IPC TM-650 2.4.19
Peel Strength (1 oz Cu / 2 oz Cu)	10.3 / 9.8 lb/in	IPC TM-650 2.4.8
Flexural Modulus	371 (×10³ psi)	—
Thermal Conductivity	0.258 W/m·K	—
Coefficient of Thermal Expansion (Z-axis)	194 ppm/°C (below Tg)	IPC TM-650 2.4.41
Flammability	Meets UL94-V0	UL94

Outgassing Properties (NASA SP-R-0022A)

Parameter	CuClad 233 Value	NASA Maximum Allowed
Total Mass Loss (TML)	0.01%	1.00%
Collected Volatile Condensable Material (CVCM)	0.01%	0.10%
Water Vapor Regain (WVR)	0.00%	—
Visible Condensate	None	—

The outgassing numbers are particularly notable: TML of 0.01% is 100× below the NASA acceptance threshold. This is what enables CuClad 233 to be used in satellite and space-qualified hardware where contamination of optical surfaces or precision mechanisms is a hard constraint.

Available Configurations

Attribute	Options
Copper Cladding Weight	1/2 oz, 1 oz, 2 oz electrodeposited (ED)
Copper Type	Standard ED; rolled (RA) copper on request
Standard Panel Sizes	36″ × 36″ (cross-plied); 36″ × 48″ (parallel-plied)
Ground Plane Options	Bonded aluminum, brass, or copper plate
LX Testing Grade	Individual piece testing with test report
RoHS Compliance	Yes

The Cross-Plied Construction Advantage — Why It Matters at 233

You’ll see the cross-plied construction mentioned in any CuClad datasheet, but the practical engineering significance is sometimes underexplained. Here’s what it actually means for CuClad 233 specifically.

In a conventional single-direction woven fiberglass PTFE laminate, the fiberglass cloth runs primarily in one direction. The PTFE fills the weave, but the material is not symmetric in the XY plane — the Dk measured along the warp direction is slightly different from the Dk measured in the weft direction. For simple one-off microwave components, this anisotropy is too small to matter. For precision coupled-line filters or broadside couplers where tight spacing tolerances determine coupling, it can shift the centre frequency measurably.

CuClad 233’s cross-plied construction places alternating fiberglass plies at 90° to each other, so at any point on the laminate surface, the fiberglass distribution is balanced in all in-plane directions. The result is genuine electrical isotropy — the Dk is the same regardless of trace orientation on the panel. This is the property that Rogers correctly identifies as unique to the CuClad series versus any competing woven or non-woven fiberglass PTFE laminate.

For CuClad 233 specifically — positioned as the stability-balanced member of the series — this isotropy combines with the additional dimensional stability from the medium glass loading to make it the most reliable CuClad grade for designs where you need to maintain tight coupling coefficients across a production run.

Arlon CuClad 233 vs. Competing RF Laminates

Understanding where CuClad 233 sits relative to alternatives helps you justify the material specification internally and communicate clearly with your fabricator.

CuClad 233 Within the CuClad Family

Material	Dk (10 GHz)	Df (10 GHz)	Glass/PTFE Ratio	Best For
CuClad 217	2.17 / 2.20	0.0009	Lowest	Minimum loss, XY isotropy critical
CuClad 233	2.33	0.0013	Medium	Balanced loss + stability
CuClad 250GT	2.40–2.60	0.0015–0.0018	Highest	Mechanical robustness priority

CuClad 233 vs. Other Common RF Substrates

Material	Dk	Df	Construction	Advantage vs. CuClad 233	Disadvantage vs. CuClad 233
Arlon CuClad 233	2.33	0.0013	Cross-plied woven PTFE/glass	— (reference)	—
Rogers RT/Duroid 5880	2.20	0.0009	Random glass fibre / PTFE	Lower Dk and loss	Less dimensional stability; no XY isotropy
Rogers RO4003C	3.55	0.0027	Ceramic-filled hydrocarbon	Better dimensional stability; FR-4 fab-compatible	Higher Dk and loss
Taconic TLY-5	2.17	0.0009	Woven glass / PTFE	Similar low-loss profile	No cross-plied isotropy claim
FR-4 (standard)	~4.5	~0.020	Woven glass / epoxy	Low cost; easy fab	Far higher loss; unsuitable above ~1 GHz
Isola IS680-280	2.80	0.0047	Woven glass / hydrocarbon-ceramic	Better dimensional stability	Higher Dk and Df

The key decision boundary is between CuClad 233 and CuClad 217. If your application is primarily loss-budget constrained and dimensional stability is not a concern, CuClad 217 has lower loss. If you’re designing a multi-element filter or coupler bank where panel-to-panel manufacturing consistency matters as much as raw insertion loss, CuClad 233’s better dimensional stability and slightly higher glass content tilts the balance in its favour.

Against RO4003C, the comparison is fundamentally different: CuClad 233 offers lower loss (Df 0.0013 vs. 0.0027) and lower Dk (2.33 vs. 3.55), but RO4003C is processable on standard FR-4 fabrication lines, which translates to broader fab availability and lower piece-part cost for non-critical designs.

RF and Microwave Applications for Arlon CuClad 233

The combination of low Dk, low dissipation factor, XY electrical isotropy, and better dimensional stability than CuClad 217 defines a specific application space. These are the use cases where CuClad 233 gets specified repeatedly:

Microwave Bandpass Filters — This is probably the most common CuClad 233 application in production RF hardware. Edge-coupled or combline bandpass filters rely on tightly controlled coupled-line spacing to set the coupling coefficient and hence the filter response shape. The dielectric constant uniformity across the panel directly determines how consistently the filter centre frequency and passband shape reproduce from piece to piece. CuClad 233’s cross-plied isotropy and tight Dk control make it the preferred substrate for narrow-band filter designs in S-band through Ku-band.

Directional Couplers — Branch-line and rat-race couplers, and microstrip directional couplers in general, are sensitive to the Dk value at the design frequency. CuClad 233’s stable Dk from low frequency through X-band and beyond means that the electrical quarter-wave sections designed into a 3 dB coupler maintain their intended electrical length across the operating band. Production couplers for transmitter monitoring, signal splitting, and reflectometer networks in radar front-ends are common applications.

Power Dividers and Combiners — Wilkinson dividers and corporate feed networks for antenna arrays require matched electrical path lengths and predictable impedance control. CuClad 233 is a frequent choice for these structures, particularly in military radar where the feed network is a large, multi-element structure. The panel-size availability (up to 36″ × 48″) is also relevant here — large antenna feed networks sometimes require full-panel layout to avoid inter-panel joins.

Low Noise Amplifier (LNA) Input Matching Networks — The input matching network of a low-noise amplifier contributes directly to system noise figure. At C-band and X-band, the difference in substrate insertion loss between CuClad 233 and a higher-loss material like RO4003C is measurable at the system level. CuClad 233 is a common choice for LNA input networks in ground-based radar, satellite receivers, and instrumentation receivers where noise figure budget is tight.

Military Radar and Electronic Warfare (EW) Hardware — CuClad 233 appears in the datasheets of every major military radar programme, ECM module, and ESM receiver that was designed from the 1990s through the present. Its qualification history in defence applications is extensive, and its inclusion in multiple approved materials lists (AMLs) for US and NATO defence programmes means specifying it carries lower programme risk than a newer material without that track record.

Phased Array Antenna Substrates — The XY isotropy discussed earlier becomes a hard requirement for phased array antenna feed networks where you need matched electrical path lengths to radiating elements oriented in multiple directions on the same panel. CuClad 233 handles this well, and its slightly better dimensional stability versus CuClad 217 makes it preferred in multi-layer phased array constructions where the laminate sees thermal cycling during assembly.

Satellite and Space Electronics — The near-zero outgassing performance (TML 0.01%, CVCM 0.01%) places CuClad 233 well within the requirements for space-qualified hardware. Satellite transponder output networks, passive RF components for payload assemblies, and satellite receiver front-ends have all used CuClad 233 as the substrate of choice.

Designing RF Circuits on CuClad 233: What to Watch

Impedance Control and Trace Width

With Dk = 2.33, a 50 Ω microstrip trace on a typical 0.031″ (0.787 mm) substrate will be approximately 2.2–2.4 mm wide. This is wider than you’d need on RO4003C (Dk 3.55) for the same impedance and thickness, which means lower resistive loss per unit length — a secondary benefit of the low-Dk material class.

Use a simulator that accounts for dispersion at your operating frequency. Rogers’ MWI-2010 impedance calculator supports CuClad material properties. For designs above 10 GHz, model the conductor loss explicitly — at these frequencies, surface roughness of the copper foil is a significant contributor to total insertion loss.

Stripline vs. Microstrip

CuClad 233 works well in both microstrip and stripline configurations. In multilayer designs, stripline benefits from the XY isotropy most directly — fields are fully contained in the dielectric, so any in-plane Dk variation directly affects impedance. The cross-plied construction’s contribution to uniformity is more impactful in stripline than microstrip, where a portion of the field travels in air above the trace.

Copper Foil Selection

Standard 1 oz or 1/2 oz electrodeposited copper is appropriate for most CuClad 233 designs. At frequencies above 10 GHz, specify smooth or very-smooth copper foil if insertion loss is critical — the skin depth at 10 GHz is roughly 0.66 μm, comparable to standard ED copper surface roughness. Rolled (RA) copper is available on special order and is the right choice for Ka-band and above.

Fabricating Arlon CuClad 233 PCBs

PTFE-based laminates like CuClad 233 demand fabrication procedures that differ from FR-4 practice. Choosing a fab house without documented PTFE laminate experience is a reliable way to get damaged through-holes and board-level reliability failures. Here’s what the process requires:

Drilling

PTFE is mechanically softer and more elastic than FR-4. Standard FR-4 drill bits and feed rates will smear rather than cut the PTFE matrix, producing a bore wall that is poorly conditioned for copper plating. Use carbide or diamond-coated drill bits specified for PTFE composites, with feed rates and stack heights matched to PTFE-grade practice. Your fab house should have documented PTFE drill programs.

Through-Hole Surface Preparation

PTFE’s chemical inertness — the same property that makes it useful as a low-friction engineering material — creates a serious adhesion problem for plated through-holes. The standard permanganate desmear chemistry used on FR-4 does not generate reactive surface sites on PTFE. Two approaches work:

Sodium etch (chemical): Products such as FluoroEtch or Poly-Etch chemically strip fluorine from the PTFE bore wall, creating reactive carbon sites that allow electroless copper to adhere. This is the most widely used production method for PTFE PCB fabrication.

Plasma treatment: An oxygen/CF₄ or oxygen/argon plasma activates the PTFE surface in a dry process. It produces clean, consistent surface activation without chemical waste, but requires the right plasma equipment and is less common in volume production shops.

Barrel cracking and PTH pull-out in PTFE boards are almost always the result of skipping or incorrectly performing this surface preparation step. Verify with your fab house that they are performing it.

Surface Finish Recommendations

For CuClad 233 microwave circuits, ENIG (Electroless Nickel Immersion Gold) is the preferred surface finish. ENIG provides a flat, solderable, wire-bondable surface with predictable electrical behaviour at microwave frequencies. HASL (Hot Air Solder Levelling) is avoided for precision RF work because the solder surface topography is too rough for consistent RF performance at frequencies above a few GHz.

Immersion silver is also used in some applications — it provides an even flatter surface than ENIG with lower loss at very high frequencies, but requires more careful handling to prevent tarnishing.

How to Order Arlon CuClad 233 Correctly

A complete material call-out for CuClad 233 should include the following parameters to avoid ambiguity:

Parameter	Example Specification
Material	CuClad 233 (Er = 2.33)
Dielectric Thickness	0.031″ (0.787 mm)
Copper Cladding	1 oz ED, double-sided
Panel Size	18″ × 24″ cut-to-size
Testing Grade	Standard or “LX” (individual piece test report)
Ground Plane	None / Bonded aluminum (if required)
RoHS Compliance	Required

The “LX” testing option is worth the additional cost for defence, space, and precision instrumentation programmes. Each laminate piece is individually tested, and a test report ships with the order. For commercial wireless infrastructure designs where lot-level traceability is sufficient, standard grade is appropriate.

Useful Resources for Arlon CuClad 233

Resource	Description	URL
Rogers CuClad 233 Product Page	Official Rogers product page with Laminate Properties Tool link	rogerscorp.com – CuClad 233
CuClad Series Datasheet (PDF)	Full Rogers CuClad 217/233/250 datasheet	rogerscorp.com datasheet PDF
Legacy Arlon CuClad Datasheet (MidwestPCB)	Historical Arlon-era CuClad series full datasheet	midwestpcb.com PDF
MatWeb CuClad 233 Data Entry	Material property database with SI/imperial conversion	matweb.com – CuClad 233
Rogers MWI Impedance Calculator	Online microstrip/stripline calculator supporting CuClad properties	rogerscorp.com resources
IPC-4103 Standard	Specification for High-Frequency (Microwave) Base Materials	ipc.org
NASA Outgassing Database	GSFC spacecraft materials outgassing data (confirms CuClad compliance)	outgassing.nasa.gov
LookPolymers CuClad 233 Entry	Cross-referenced material property aggregator	lookpolymers.com

5 FAQs About Arlon CuClad 233

Q1: Is there a meaningful RF performance difference between Arlon CuClad 233 and CuClad 217?

Yes, but it’s application-dependent. CuClad 217 has Dk 2.17 and Df 0.0009 versus CuClad 233’s Dk 2.33 and Df 0.0013. In terms of microstrip insertion loss, the difference at 10 GHz on a typical 0.031″ substrate is real but modest — on the order of 0.01–0.02 dB/cm. For a short matching network or coupler, the difference is negligible. For a long feed network in a large phased array antenna running at X-band, it accumulates. The more impactful difference for most production applications is dimensional stability: CuClad 233’s medium glass loading gives it better stability through the manufacturing process, which often translates to better yield on tight impedance-controlled designs.

Q2: Can I design a circuit for CuClad 217 and just switch to CuClad 233?

Not without re-optimisation. The Dk values differ by about 7%, which directly affects trace widths and electrical lengths. A 50 Ω microstrip trace at the same dielectric thickness will be narrower on CuClad 233 than on CuClad 217. Any quarter-wave or half-wave resonant element will be shorter. For simple matching networks, a layout re-spin after material change is straightforward. For a narrowband filter designed around CuClad 217, substituting CuClad 233 without re-optimising will shift the passband centre frequency and likely detune the return loss.

Q3: Does Arlon CuClad 233 require a PTFE-qualified fabricator?

Yes, without exception. CuClad 233 is a PTFE-composite laminate and requires the same special processing that all PTFE PCB materials need: PTFE-grade drill bits, controlled feed rates, sodium etch or plasma treatment for through-hole surface activation, and appropriate handling practices (PTFE is sensitive to contamination from standard FR-4 shop chemicals). Submitting a CuClad 233 design to a shop that only processes FR-4 and ceramic-filled hydrocarbon laminates is a fabrication quality risk. Always confirm PTFE laminate experience before placing the order.

Q4: Is Arlon CuClad 233 available from stock, or is it a long-lead material?

Availability varies by thickness and copper cladding combination. Standard configurations — 0.031″ with 1 oz copper, for example — are typically carried in stock by Rogers distributors and RF specialty PCB suppliers. Less common thicknesses, single-sided cladding, or large master sheet formats may require a short lead time. The “LX” grade (individual piece testing) generally requires a longer lead time because of the additional testing step. For defence programme planning purposes, confirm availability with your Rogers distribution channel early in the design phase.

Q5: How does CuClad 233 compare to Rogers RT/Duroid 5880 for filter applications?

RT/Duroid 5880 (Dk 2.20, Df 0.0009) has lower loss than CuClad 233, but it uses a random (non-woven) glass microfibre reinforcement rather than cross-plied woven fiberglass. That means it doesn’t have the same XY isotropy, and its Dk uniformity across a panel can be slightly less consistent than CuClad 233’s. For filters where tight coupling coefficient control and repeatable centre frequency across a production run are primary requirements, CuClad 233’s cross-plied construction and controlled Dk uniformity can outperform the lower-loss RT/Duroid 5880 at the production yield level. For a one-off prototype where minimum insertion loss is the only criterion, RT/Duroid 5880 wins on raw loss performance.

Summary: When CuClad 233 Is the Right Choice

Arlon CuClad 233 fills the design space between the ultra-low-loss CuClad 217 and the mechanically robust CuClad 250 with a combination that many production RF engineers find more practical for real-world designs than either extreme. If you’re building filters that have to hit a tight centre frequency specification across a production run, couplers that need matched electrical behaviour regardless of trace orientation, or phased array feed networks where dimensional stability through assembly matters as much as raw insertion loss, CuClad 233 is the substrate that resolves those requirements in a single material choice.

Its application history in military radar, EW hardware, satellite communications, and precision microwave passive components is extensive. It has a long qualification track record in defence AMLs. And because it processes with the same PTFE fabrication practices as CuClad 217, a fab shop that can handle one can handle the other — meaning you’re not adding supply chain complexity by choosing CuClad 233 for dimensional-stability-sensitive designs while using CuClad 217 for loss-critical ones.