Arlon CLTE-MW is a PTFE/ceramic/glass laminate engineered for 5G and millimeter wave PCB applications. Explore complete specs, loss tangent data, fabrication tips, material comparisons, and FAQs in this PCB engineer’s guide.

If you’ve been hunting for a substrate that can handle 5G millimeter wave frequencies without breaking your budget or your fabrication shop, Arlon CLTE-MW deserves a serious look. As someone who’s spent time evaluating RF laminates for demanding antenna and amplifier designs, I can tell you that getting material selection wrong at mmWave frequencies isn’t just a performance issue — it’s a system failure waiting to happen.

This guide covers everything you need to know about Arlon CLTE-MW: what it’s made of, how its key specs translate to real-world design decisions, where it fits and where it doesn’t, and how it compares to the competition. Whether you’re designing a 28 GHz 5G phased array or a 40 GHz point-to-point link, the information here will help you decide if CLTE-MW belongs in your next build.

What Is Arlon CLTE-MW? Understanding the Material Background

Arlon CLTE-MW is a ceramic-filled, woven glass reinforced PTFE composite laminate originally developed by Arlon Electronic Materials — now part of Rogers Corporation after their acquisition of Arlon LLC. The CLTE series has long been one of Arlon’s flagship microwave laminate families, and the CLTE-MW variant was specifically engineered to address the growing demand for cost-effective, high-performance substrates in 5G and other millimeter wave applications.

The “CLTE” designation stands for Coefficient of Linear Thermal Expansion — a name that reflects the product line’s primary design goal: minimizing dimensional and electrical changes due to temperature variation. The “-MW” suffix indicates its optimization specifically for millimeter wave frequency ranges.

Rogers acquired Arlon in 2015, which means CLTE-MW is now sold under the Rogers Corporation umbrella. However, the Arlon branding and product heritage remain strong in the industry, and engineers continue to refer to these materials as “Arlon CLTE-MW” in their daily work. If you’re working with an Arlon PCB supplier, this context matters for procurement and technical support conversations.

Material Composition: Why PTFE + Ceramic + Spread Glass?

Understanding why Arlon CLTE-MW performs the way it does starts with understanding its three-component material system.

PTFE Base Matrix

Polytetrafluoroethylene (PTFE) is the workhorse of high-frequency laminate systems. Its inherently non-polar molecular structure means it produces almost no dielectric loss, even as frequencies climb into the millimeter wave range. PTFE-based materials have been the substrate of choice for radar, satellite, and defense RF circuits for decades.

The downside of pure PTFE? It’s dimensionally unstable, difficult to process, and thermally soft. Raw PTFE laminates can creep under clamping pressure and require special drilling, through-hole preparation, and bonding procedures. The ceramic and glass additions in Arlon CLTE-MW directly address these weaknesses.

Ceramic Filler Loading

The ceramic powder filler in Arlon CLTE-MW serves multiple critical functions. First, it raises the dielectric constant from PTFE’s baseline of approximately 2.1 to a more useful value near 3.0, which allows for more compact circuit geometries. Second, it improves thermal conductivity significantly compared to unfilled PTFE. Third, and crucially for temperature-sensitive applications, the ceramic filler stabilizes the dielectric constant over temperature — reducing the phase shifts that plague pure PTFE circuits as operating temperatures change.

The “high filler loading” mentioned in CLTE-MW’s design specifications also helps minimize the influence of the glass weave on electromagnetic wave propagation, a phenomenon known as the glass weave effect that becomes increasingly problematic as frequency rises.

Spread Glass Reinforcement

At millimeter wave frequencies above 20 GHz, conventional woven glass reinforcement can cause serious problems. The alternating resin-rich and glass-rich regions of a standard woven fabric create periodic variations in local dielectric constant. At high enough frequencies, these variations act as a diffraction grating, causing signal skew, insertion loss variation, and unwanted radiation.

Arlon CLTE-MW uses spread glass reinforcement — a weaving process that flattens and spreads the glass bundles to create a much more uniform fiber distribution. Combined with the high ceramic filler loading, this dramatically reduces glass weave effects. For PCB designers working above 20 GHz, this is not a minor detail; it’s the difference between a design that measures like a simulation and one that doesn’t.

Arlon CLTE-MW Key Specifications and Properties

Here’s a consolidated view of the material properties that matter most for RF and mmWave PCB design:

Electrical Properties

Property	Value	Condition
Dielectric Constant (Dk)	~3.00	10 GHz
Loss Tangent (Df)	0.0015	10 GHz
Dielectric Strength	630 V/mil	—

Thermal Properties

Property	Value
Z-axis CTE	30 ppm/°C
Thermal Conductivity	0.42 W/(m·K)
Moisture Absorption	0.03%

Mechanical and Fabrication Properties

Property	Value
Available Thicknesses	3 mil, 4 mil, 5 mil, 6 mil, 7 mil, 8 mil, 10 mil (7 options)
Copper Foil Options	Rolled, Reverse Treated ED, Standard ED
Flammability Rating	UL94 V-0

Why These Numbers Matter in Practice

Loss tangent of 0.0015 at 10 GHz is genuinely impressive. For comparison, standard FR-4 runs 0.020 or higher, and even well-regarded hydrocarbon laminates like Rogers RO4350B come in at 0.0037. In a 10-inch signal path at 28 GHz, the difference between 0.0037 and 0.0015 Df can mean 2–3 dB of additional insertion loss — easily the difference between a working system and a failing link budget.

Z-axis CTE of 30 ppm/°C is excellent for plated through-hole (PTH) reliability. Copper expands at roughly 17 ppm/°C. The closer a laminate’s z-axis expansion tracks copper, the less mechanical stress accumulates at barrel-to-pad interfaces during thermal cycling. For boards expected to survive hundreds of thermal cycles — common in automotive, aerospace, and outdoor telecom applications — this matters enormously.

Moisture absorption of 0.03% is one of the lowest values available in any commercial laminate. Water has a dielectric constant of approximately 80. Even trace moisture uptake causes measurable Dk drift, which translates directly into impedance variation and phase error. For outdoor 5G base station antennas or automotive radar modules that see humidity cycling over their lifetime, 0.03% moisture absorption provides excellent long-term electrical stability.

Seven thickness options from 3 to 10 mils directly addresses one of the core challenges in mmWave board design: controlling signal-to-ground spacing. At 28 GHz and above, dielectric thickness drives impedance, conductor loss, and surface wave behavior. Having ultra-thin options down to 3 mils gives designers the flexibility to hit characteristic impedance targets on very narrow trace widths without needing excessive stack-up compensations.

Arlon CLTE-MW vs. Competing Materials: Where Does It Fit?

PCB material selection is always a trade-off exercise. Here’s how Arlon CLTE-MW stacks up against the alternatives you’re most likely to encounter:

Arlon CLTE-MW vs. Rogers RO4350B

Parameter	Arlon CLTE-MW	Rogers RO4350B
Dielectric Constant	~3.00	3.48
Loss Tangent (10 GHz)	0.0015	0.0037
Z-axis CTE	30 ppm/°C	32 ppm/°C
Moisture Absorption	0.03%	0.06%
Processing	PTFE-specialized	FR-4 compatible
Typical Cost	Higher	Moderate

RO4350B is arguably the most popular high-frequency laminate on the market because it processes like FR-4. If your fab has no PTFE experience, RO4350B is the safer production choice. But at 28 GHz and above, the 2.5x difference in loss tangent between RO4350B and CLTE-MW starts showing up clearly in system-level performance, particularly in antenna efficiency and amplifier gain.

Arlon CLTE-MW vs. Arlon CLTE-XT

The CLTE-XT is Arlon’s premium option within the CLTE family. It achieves even lower loss (Df around 0.0012), lower moisture absorption, tighter Dk and thickness tolerances, and better phase stability vs. temperature than CLTE-MW. If you’re building a temperature-sensitive phased array radar or a space-grade communications module, CLTE-XT is worth the cost premium. For most commercial 5G applications where cost efficiency matters and the moderate temperature range is acceptable, CLTE-MW hits a better price-performance point.

Arlon CLTE-MW vs. Rogers RT/duroid 5880

RT/duroid 5880 is a PTFE/glass composite with a Dk of 2.2 and an exceptionally low Df of 0.0009 — the benchmark for ultra-low-loss mmWave applications. It’s widely used in radar front ends and satellite receiver chains where insertion loss is critical. CLTE-MW’s higher dielectric constant (3.0 vs. 2.2) allows for more compact circuitry, while RT/duroid 5880 offers lower absolute loss. For very wide-band antennas or highest-sensitivity receiver designs, RT/duroid 5880 wins on raw loss performance. For compact modules where size constraints are real, CLTE-MW’s higher Dk provides useful design flexibility.

Target Applications for Arlon CLTE-MW

Arlon CLTE-MW was designed with a specific set of applications in mind, and it genuinely excels in these environments:

5G Millimeter Wave Infrastructure

The 5G NR FR2 bands (24.25–52.6 GHz) place extreme demands on substrate materials. Tight Dk tolerances, low loss, and physical thickness options that enable proper signal-to-ground spacing make Arlon CLTE-MW a natural fit for 5G mmWave antenna modules, massive MIMO arrays, and beamforming front-end circuits. The spread glass reinforcement is particularly relevant here — phase coherence across an antenna array depends on identical electrical path lengths, and glass weave effects are a real source of inter-element phase error.

Radar Systems (Automotive and Defense)

Automotive radar operating at 77–79 GHz for ADAS applications, and defense radar at various mmWave bands, both benefit from CLTE-MW’s combination of low loss, low moisture absorption, and excellent dimensional stability. The 30 ppm/°C z-axis CTE is critical for multilayer radar modules that must survive the thermal extremes of under-hood automotive environments (-40°C to +125°C).

Amplifiers and Active Components

Power amplifiers and low-noise amplifiers (LNAs) benefit directly from low-loss substrates. Every 0.1 dB of substrate insertion loss is 0.1 dB of added noise figure in a receive chain or 0.1 dB of lost output power in a transmit path. For designs where thermal management is also a concern — which describes most power amplifier applications — CLTE-MW’s thermal conductivity of 0.42 W/(m·K) helps move heat away from active devices more effectively than lower-conductivity PTFE alternatives.

Antennas, Baluns, Couplers, and Filters

These passive components all benefit from stable Dk, low loss, and predictable dimensional behavior over temperature. Antenna designs are particularly sensitive to Dk variation because it directly affects resonant frequency. A patch antenna designed for 28 GHz on a substrate whose Dk drifts with temperature will shift in resonant frequency as the environment changes — not acceptable behavior in a production system. CLTE-MW’s temperature-stable dielectric constant helps these designs perform consistently in the field.

PCB Fabrication Considerations for Arlon CLTE-MW

PTFE-based laminates require different handling and processing than epoxy/glass substrates. Before sending a CLTE-MW design to your PCB fabricator, make sure they have verified experience with the following process steps:

Drilling and Through-Hole Preparation

PTFE is soft and tends to smear during drilling, creating a non-conductive PTFE film on the drilled hole wall that prevents copper adhesion during electroless plating. Proper through-hole preparation requires a sodium or plasma etch step to chemically activate the PTFE surface. Skipping this step results in unreliable or absent plated through-hole copper and dramatic reliability failures in the field.

Copper Foil Selection

CLTE-MW supports three copper foil options: rolled (RA) copper, reverse treated ED copper, and standard ED copper. For high-frequency signal layers, rolled or reverse-treated ED copper offers lower surface roughness, which directly reduces conductor loss at high frequencies. At 28 GHz, skin depth in copper is approximately 0.4 μm — comparable to the surface roughness of standard ED copper. Rough surface copper can add 20–40% additional conductor loss compared to smooth copper at these frequencies. This is not an area to compromise on for mmWave designs.

Dimensional Stability and Registration

PTFE laminates have higher thermal expansion than glass/epoxy boards in the x-y plane. For multilayer designs, accurate layer-to-layer registration requires attention to lamination parameters and careful design of the board’s panel tooling system. Discuss expected shrinkage compensation factors with your fabricator before finalizing your design data.

Hybrid Stackups

It’s common in real-world designs to use CLTE-MW for the critical RF signal layers while using lower-cost materials for DC power distribution and digital control layers. These hybrid stackups can provide excellent system-level cost optimization. However, the CTE mismatch between PTFE-based layers and epoxy-glass layers must be managed carefully to avoid delamination during thermal cycling. Work with a fabricator who has tested and qualified hybrid stackup designs before committing to production.

Material Selection Decision Framework

Use this quick-reference table to help decide whether Arlon CLTE-MW fits your project:

Design Requirement	CLTE-MW Fit
Frequency above 20 GHz	✅ Excellent
Very low insertion loss required	✅ Excellent
Tight impedance tolerance needed	✅ Excellent
Moisture exposure expected	✅ Excellent
PTFE fabrication capability at fab	Required
Budget-constrained project	⚠️ Consider RO4350B
Extreme phase stability needed	⚠️ Consider CLTE-XT
Frequency below 10 GHz	⚠️ Overspecified
Large volume, cost-sensitive	⚠️ Evaluate alternatives

Useful Resources for Arlon CLTE-MW Design and Procurement

These references will be useful as you move from material selection into detailed design and procurement:

• Rogers Corporation CLTE-MW Product Page — rogerscorp.com/clte-mw-laminates — Includes the Laminate Properties Tool for detailed, filterable specification data
• Rogers Laminate Properties Tool — Interactive database for comparing materials across key electrical, thermal, and mechanical parameters
• IPC-4103 Specification — The industry standard governing PTFE-based high-frequency laminate materials; useful for understanding qualification requirements
• Arlon/Rogers Microwave Materials Design Guide — Available from authorized Rogers distributors; covers fabrication guidelines for PTFE laminates in detail
• Saturn PCB Toolkit — Free impedance calculator that supports PTFE laminate stack-up analysis, useful for trace width and impedance target calculations
• Matweb Material Database — matweb.com — Includes Arlon CLTE material property listings useful for cross-reference and thermal modeling
• Everything RF CLTE-MW Listing — Parametric search and distributor sourcing for CLTE-MW materials

Frequently Asked Questions About Arlon CLTE-MW

Q1: Is Arlon CLTE-MW the same as Rogers CLTE-MW?

Yes. Rogers Corporation acquired Arlon LLC in 2015. CLTE-MW was originally developed and marketed by Arlon but is now manufactured and distributed by Rogers Corporation. The product specifications and performance characteristics are the same material. In practice, engineers and procurement teams still commonly refer to it as “Arlon CLTE-MW,” and it’s sold under the Rogers brand. When sourcing the material, search for both “Arlon CLTE-MW” and “Rogers CLTE-MW” to ensure full distributor coverage.

Q2: Can I process Arlon CLTE-MW on a standard FR-4 PCB production line?

Not directly. PTFE-based laminates require specialized through-hole preparation (plasma or sodium etch activation), different drill parameters, and modified lamination procedures compared to FR-4 processing. Using a fabricator without PTFE experience will result in PTH reliability failures and potentially delamination. Always verify that your PCB manufacturer has documented experience processing PTFE laminates before committing a CLTE-MW design to production.

Q3: What is the maximum operating frequency for Arlon CLTE-MW?

Rogers characterizes CLTE-MW for use up to approximately 40 GHz based on its material properties. In practice, engineers have used it in designs operating beyond 40 GHz, but beyond this range, careful full-wave simulation and physical testing are essential. The spread glass reinforcement helps maintain consistent electrical behavior at higher frequencies, but substrate and conductor loss accumulate rapidly above 40 GHz and need to be verified against your system link budget.

Q4: How does moisture absorption of 0.03% affect long-term performance?

Water has a dramatically higher dielectric constant (~80) than most PCB substrates. Even small amounts of absorbed moisture shift the effective Dk of a laminate, which causes impedance variations and phase errors in precision RF circuits. CLTE-MW’s 0.03% moisture absorption is among the lowest available in any commercial laminate. For a 3-mil-thick substrate, this corresponds to an extremely small absolute volume of water uptake, resulting in negligible Dk shift over the material’s operating life. This makes CLTE-MW well-suited for outdoor, marine, or humid industrial environments.

Q5: What copper foil type should I specify for 28 GHz designs on CLTE-MW?

For designs operating at 28 GHz and above, specify reverse treated ED (RTED) or rolled annealed (RA) copper whenever possible. At these frequencies, skin depth is on the order of surface roughness for standard ED copper, meaning conductor loss increases significantly with rough surfaces. Reverse treated and rolled copper foils offer meaningfully lower surface roughness, reducing conductor loss by 20–40% compared to standard ED copper at mmWave frequencies. This is one of the most impactful low-cost design improvements available in high-frequency PCB design.

Summary: When Arlon CLTE-MW Makes Sense

Arlon CLTE-MW occupies a well-defined and genuinely useful position in the RF laminate landscape. It’s not the cheapest material, and it’s not the absolute lowest-loss option available. What it is, however, is a well-engineered balance of very low loss, excellent dimensional stability, superb moisture resistance, ultra-thin thickness options, and spread glass reinforcement that directly addresses the real failure modes of mmWave board designs.

For engineers building 5G millimeter wave antennas, automotive radar modules, defense radar front ends, or satellite communication hardware — especially designs where physical thickness constraints drive the substrate selection — Arlon CLTE-MW deserves a place on your shortlist. Pair it with a fabricator who knows how to process PTFE laminates correctly, specify the right copper foil for your frequency range, and you have a substrate system capable of supporting some of the most demanding RF designs in production today.

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