Arlon AD250C Laminate: Datasheet, Properties & PCB Design Guide

If you’ve been tasked with designing a base station antenna feed network, a radar manifold, or a high-volume commercial wireless PCB where insertion loss and passive intermodulation have to be tightly controlled, the Arlon AD250C laminate will show up on your shortlist quickly. It’s one of those materials that experienced RF engineers keep coming back to precisely because it hits an unusual combination: genuinely low loss, controlled dielectric constant, low PIM, and a price point that makes it viable for production-scale telecom hardware — not just R&D prototypes.

This guide pulls together the full technical picture on Arlon AD250C: what’s in it, what the key properties actually mean for your design, how it compares to competing materials, and the practical fabrication and layout considerations you need to know before you submit your Gerbers to a PTFE-capable PCB shop.

What Is Arlon AD250C? Background and Material Composition

Arlon was originally a standalone specialty laminate manufacturer founded in 1969. Rogers Corporation acquired Arlon in 2015, and the AD Series brand now sits under Rogers’ Advanced Electronics Solutions division. The Arlon PCB material heritage is fully intact — the AD Series datasheet, part numbers, and brand identity have been preserved — but the manufacturing and distribution infrastructure is Rogers’.

The “AD” in AD250C stands for Antenna Dielectric, which tells you immediately what this family was engineered for. The “250” refers to a nominal dielectric constant of 2.50. The “C” suffix marks the third generation of the formulation — the progression went from the original PTFE/woven glass (“L” designation), to ceramic-filled layers added for cost and lower Z-axis CTE (“A” designation), to the current “C” version which increases ceramic-filled layers further, reducing both dissipation factor and Z-axis expansion compared to its predecessors.

The construction of AD250C is a composite of three material components working together: a PTFE fluoropolymer matrix provides the base low-loss dielectric foundation; woven fiberglass reinforcement gives the laminate mechanical rigidity and reduces CTE in the X-Y plane; and microdispersed ceramic filler embedded within the PTFE layers drives thermal stability of the dielectric constant and reduces Z-axis expansion beyond what plain PTFE/glass can achieve. It’s the ceramic component that separates the AD Series from basic PTFE/glass laminates — it’s the reason AD250C maintains phase stability across temperature cycling, which is critical for outdoor antenna applications where boards go from −40°C winter nights to 85°C in a sun-baked radome.

Arlon AD250C Electrical Properties

Dielectric Constant and Loss Tangent

These are the numbers that drive every RF design decision, and they’re where AD250C earns its place in the spec.

Property	Value	Test Condition	Test Method
Dielectric Constant (Dk)	2.50	10 GHz	IPC TM-650 2.5.5.6c
Dk Tolerance	±0.04	—	Production controlled
Dissipation Factor (Df)	0.0014	10 GHz	IPC TM-650 2.5.5.6c
Dissipation Factor	0.0011	1 GHz	—
Volume Resistivity	>10⁷ MΩ·cm	—	IPC TM-650 2.5.2.1
Surface Resistivity	>10⁷ MΩ	—	IPC TM-650 2.5.2.1

The Dk tolerance of ±0.04 is tight by commercial PTFE standards. That level of consistency matters enormously in antenna phase array designs, where impedance matching depends on predictable trace dimensions across every manufactured board. If the dielectric constant wanders, your calculated trace width for 50Ω won’t actually be 50Ω in production, and you start chasing yield issues that trace back to material variation rather than anything in your fabrication process.

The 0.0014 dissipation factor at 10 GHz is the headline loss figure. To put that in practical terms: at base station operating frequencies (700 MHz to 5.8 GHz), the loss tangent is even lower than the 10 GHz value, typically around 0.0011 at 1 GHz. For a 100mm microstrip transmission line at 3.5 GHz, the dielectric loss contribution from AD250C is a fraction of a dB — in most designs, copper conductor losses will dominate long before the dielectric becomes the limiting factor.

PIM Performance

Passive Intermodulation is one of the less visible but increasingly critical specifications for antenna materials used in multi-carrier base station applications. When two or more high-power carrier signals pass through an antenna assembly, non-linear interactions in the materials create intermodulation products — spurious signals that can fall inside a receive band and degrade sensitivity.

AD250C delivers ultra-low PIM values as low as −165 dBc, though the practical PIM performance depends heavily on the copper foil type. Rogers specifies PIM values using S1 smooth foil on 0.030″ and 0.060″ thick laminates using their internal test method. If you’re designing for a PIM-sensitive base station antenna, verify PIM performance with the exact copper and finish combination you plan to run in production — PIM is one of those specs where lab-to-lab variability is real and worth checking.

Arlon AD250C Mechanical and Thermal Properties

Thermal Properties

Property	Value	Units	Test Method
Coefficient of Thermal Expansion (X-axis)	14–16	ppm/°C	IPC TM-650 2.4.41
Coefficient of Thermal Expansion (Y-axis)	14–16	ppm/°C	IPC TM-650 2.4.41
Coefficient of Thermal Expansion (Z-axis)	40–50	ppm/°C	IPC TM-650 2.4.41
Thermal Conductivity	0.42	W/m·K	ASTM C518
Decomposition Temperature (Td)	>300	°C	TGA
Operating Temperature Range	−55 to +125	°C	—

The X/Y CTE of 14–16 ppm/°C is close to copper’s CTE of approximately 17 ppm/°C. That matching matters for BGA solder joint reliability and for maintaining pad registration across temperature cycles. Earlier PTFE/glass laminates without ceramic had significantly higher X-Y CTE, which created reliability concerns in assemblies exposed to repeated thermal cycling. The ceramic filler in AD250C directly addresses this.

The Z-axis CTE of 40–50 ppm/°C is higher than the X/Y values, as expected for laminate materials, but still substantially better than unfilled PTFE. In plated through-holes, Z-axis expansion during thermal excursions is what creates barrel stress and fatigue cracking. The lower Z-axis CTE of AD250C compared to standard PTFE/glass improves PTH reliability over lifetime thermal cycling — an important consideration for outdoor infrastructure hardware that has to survive years of daily temperature swings.

Mechanical Properties

Property	Value	Units
Tensile Strength (X-axis)	85	MPa
Flexural Modulus	2,200	MPa
Peel Strength (1 oz copper)	≥4.0	N/mm (lbs/in)
Water Absorption	<0.02	%
Flammability	V-0	UL 94

The low water absorption of <0.02% is not just a mechanical property — it directly protects electrical performance in outdoor installations. Moisture ingress shifts the dielectric constant of most laminate materials. PTFE’s near-zero water uptake means the Dk of AD250C stays stable whether the board is installed in Arizona desert heat or Scottish coastal humidity.

Available Thicknesses and Copper Options

Understanding available configurations is essential before you commit to a stackup. These are the standard commercially available options — non-standard thicknesses can sometimes be ordered for high-volume programs.

Standard Dielectric Thicknesses

Thickness (inches)	Thickness (mm)	Notes
0.015″	0.381 mm	Common for single-layer filters
0.020″	0.508 mm	—
0.030″	0.762 mm	Popular for microstrip antenna work
0.060″	1.524 mm	Standard for thicker feed network boards
0.062″	1.575 mm	—

Thicker dielectrics can be developed to customer specifications for high-volume programs — the standard range covers the majority of antenna and feed network applications.

Copper Foil Options

Foil Type	Description	Best For
ED (Electrodeposited)	Standard copper foil	General microwave circuits
S1 (Special Smooth)	Smoother surface, lower conductor loss	PIM-sensitive antenna designs
IM Foil (Inverted Mass)	High peel strength	Applications needing robust adhesion
Reverse Treated	Enhanced peel strength	High-power amplifier boards

For PIM-critical antenna work, the S1 smooth foil is the recommended choice. Rougher copper surfaces create micro-scale surface area for non-linear effects that worsen PIM performance. If PIM is in your specification, this copper choice is not optional.

Arlon AD250C vs. Competing RF Laminates

One question that comes up frequently in material selection meetings: why AD250C and not RO4350B, RT/duroid 5880, or Taconic TLX-8? The answer depends on your priority ranking between loss, PIM, dimensional stability, processability, and cost.

Material	Dk	Df at 10 GHz	Z-CTE (ppm/°C)	PIM Rating	Processability	Cost Level
Arlon AD250C	2.50	0.0014	40–50	Very Low	Standard PTFE	Medium-Low
Rogers RO4350B	3.48	0.0037	46	Moderate	FR4-like	Low
Rogers RT/duroid 5880	2.20	0.0009	237 (Z)	Low	Requires PTFE process	High
Taconic TLX-8	2.55	0.0019	210 (Z)	Low	PTFE process	Medium
Isola IS680 AG338	3.38	0.0025	38	Moderate	Modified FR4	Low

Where AD250C wins: it offers one of the lowest dissipation factors available at its price point, with controlled Dk tolerance tighter than most alternatives in the 2.5 range, excellent PIM performance with S1 copper, and far better Z-axis CTE than RT/duroid 5880. If you need Dk below 2.3, RT/duroid 5880 is still the choice. If PIM is not a concern and the operating frequency is under 6 GHz, RO4350B is cheaper and easier to process. But for base station antenna feed networks, 5G sub-6 GHz infrastructure, and radar manifolds where you need low loss, low PIM, and stable Dk across temperature — AD250C is purpose-built.

AD250C PCB Design Guide

Transmission Line Design on AD250C

With Dk = 2.50, impedance calculations for microstrip lines produce slightly wider traces than you’d get on a higher-Dk material. For 50Ω microstrip on a 0.030″ (0.762 mm) AD250C substrate with 1 oz copper, the trace width runs approximately 2.2–2.4 mm depending on copper thickness and the exact Dk realized at the operating frequency. Always verify with an electromagnetic field solver or controlled-impedance calculation tool — don’t rely on rule-of-thumb formulas at microwave frequencies.

Stripline configurations on AD250C work well for multilayer antenna and combiner designs. The tighter Dk tolerance of ±0.04 gives you more confidence that your modeled impedance will match the fabricated board, which simplifies the iteration process.

Stackup Considerations for Multilayer AD250C Boards

AD250C laminates are fully compatible with standard PTFE PCB processing. When designing multilayer stacks with AD250C, there are several practical points to keep in mind:

Use PTFE-compatible prepreg or bonding layers. Standard FR4 prepreg is not compatible — it cures at different temperatures and creates adhesion and mechanical mismatch issues at the layer interfaces. Rogers and Arlon offer compatible bonding films for lamination.

Hybrid stackups mixing AD250C with FR4 layers for non-RF routing layers are done in practice but require careful management at the press stage. The PTFE material softens and flows differently than FR4 under lamination temperature and pressure. Work with your PCB manufacturer early in the design process if you’re considering a hybrid stack.

Drilling and Hole Preparation

PTFE materials are soft and gummy compared to FR4 — they behave differently under the drill bit. Drill parameters need to be tuned for PTFE to avoid hole wall smearing, bell-mouthing, and delamination. Experienced PTFE fabricators run lower drill speeds, use sharper tooling, and cool the process carefully. If your intended PCB shop doesn’t have documented experience with PTFE laminates, this is not the job for them to learn on.

Sodium naphthalene etching (or plasma etching as a cleaner alternative) of through-hole walls before copper plating is standard for PTFE-based materials. The fluoropolymer surface is inherently non-wettable and doesn’t accept copper plating adhesion without surface activation. Skipping or inadequately performing this step produces poor PTH reliability — one of the most common failure modes on PTFE boards built by shops without proper process controls.

Soldering and Assembly

AD250C’s operating temperature range of −55°C to +125°C comfortably covers standard lead-free reflow profiles. PTFE itself has excellent high-temperature stability — decomposition temperature exceeds 300°C — so standard SMT assembly does not threaten the laminate. The low water absorption minimizes any pre-bake requirements that are common with some high-Dk ceramic-filled materials.

Layout Best Practices for Low PIM

To preserve the low PIM properties of AD250C in a finished assembly:

Avoid sharp corners on high-power transmission lines. Use smooth radii on any bends in RF lines — 45° chamfers are acceptable but curved bends are better for PIM-critical designs. Sharp corners create current crowding that generates local non-linearities.

Minimize unnecessary via transitions in high-current RF paths. Each via transition introduces a small discontinuity and a potential PIM source. Route RF signals on a single layer where possible and keep transitions to the absolute minimum needed.

Specify tight trace width and spacing tolerances with your fab — typically ±0.025 mm or better on controlled-impedance lines for microwave work. Trace width variation directly changes the realized impedance and insertion loss profile.

Typical Applications of Arlon AD250C

AD250C is specifically designed for base station antenna applications, commercial antennas, digital audio broadcasting antennas including satellite radio, and radar manifolds and feed networks. In practice, engineers use it in:

Base station antenna corporate feed networks — the combining and splitting structures that distribute signal across multiple radiating elements in a panel antenna. This is the core application, where both insertion loss and PIM directly affect system performance at the base station level.

5G sub-6 GHz massive MIMO antenna panels, where antenna element count is high and the feed structure losses must be minimized to avoid excessive total antenna gain degradation.

Satellite ground station receive and transmit chains, where wide operating temperature range and phase stability across temperature are essential for maintaining beam pointing accuracy.

Radar feed networks and manifolds in commercial weather radar and traffic monitoring systems, where low loss and dimensional stability across environmental conditions define system reliability.

Useful Technical Resources for Arlon AD250C

Resource	Description	Link
Rogers AD Series Datasheet (AD250C, AD255C, AD300D, AD350A)	Official datasheet with full property tables	rogerscorp.com
Rogers Laminate Properties Tool	Interactive tool to filter and compare all Rogers/Arlon laminates	rogerscorp.com/laminate-properties
Rogers MWI-2010 Impedance Calculator	Microstrip and stripline impedance calculator for Rogers materials	rogerscorp.com/calculators
MatWeb AD250C Data Entry	Material property database with converted units for engineering calculations	matweb.com
IPC TM-650 Test Methods	Full library of IPC test methods referenced in AD250C datasheet	ipc.org/tm-650
Cirexx AD Series PDF (Legacy Arlon)	Original Arlon AD Series technical PDF with dielectric constant vs. frequency graphs	cirexx.com/AD-Series.pdf
Rogers PCB Design Guidelines for PTFE Laminates	Application notes on drilling, plating, and processing PTFE circuit boards	rogerscorp.com/resources
UL Prospector AD250 Entry	Physical, mechanical, and electrical specs in UL’s materials database	ulprospector.com

Arlon AD250C FAQs

Q1: What is Arlon AD250C and who makes it today?

Arlon AD250C is a PTFE/woven fiberglass/microdispersed ceramic composite laminate designed for RF and microwave PCB applications, particularly base station antenna and feed network circuits. Arlon Electronic Materials was acquired by Rogers Corporation in 2015. The AD250C product line is now manufactured and sold under Rogers Corporation’s Advanced Electronics Solutions division, retaining the Arlon brand name. When you order AD250C material through Rogers or their distributors, you’re getting the same material specification but from Rogers’ manufacturing infrastructure.

Q2: How does the “C” designation in AD250C differ from earlier AD Series versions?

The original PTFE and woven fiberglass formulations used an “L” suffix. Increased demand for lower-cost versions led to ceramic-filled layers replacing some of the unfilled resin layers — these were the “A” designation products. The “C” designation represents a further increase in ceramic-filled layers, which reduced both Z-axis thermal expansion and dissipation factor values beyond what the “A” generation achieved. In practical terms, AD250C has lower insertion loss and better thermal stability than AD250A for the same nominal dielectric constant.

Q3: Can AD250C be processed on standard FR4 PCB fabrication equipment?

Partially. AD250C is fully compatible with standard PTFE printed circuit board substrate processes. However, the key word is “PTFE processes” — not FR4 processes. PTFE-based materials require specific drilling parameters, sodium or plasma etch surface activation of through-holes before plating, and lamination at different temperatures and pressures than FR4. A shop that only processes FR4 is not equipped to produce reliable AD250C boards. Always verify that your intended PCB manufacturer has active experience with PTFE laminates and can provide evidence of controlled-impedance yields on similar materials.

Q4: What is the controlled dielectric constant tolerance of AD250C, and why does it matter?

AD250C carries a dielectric constant tolerance of ±0.04 across the production population. For antenna designs, the Dk tolerance directly determines how well your calculated trace impedance matches the realized impedance in fabrication. A tighter Dk tolerance means less impedance variation board-to-board, which translates to higher antenna matching yields and more consistent radiation patterns across production runs. Competing materials in this frequency range sometimes carry ±0.05 or wider tolerances — the ±0.04 of AD250C is among the tightest available at this price point.

Q5: How does AD250C perform in outdoor applications with wide temperature swings?

This is one of the material’s strongest points. The ceramic filler in AD250C provides a lower thermal coefficient of the dielectric constant (TCεr) compared to unfilled PTFE/glass. This means the Dk — and therefore the electrical behavior of your antenna or filter — stays more consistent as temperature changes from −40°C in winter to +85°C in a sun-heated radome. Phase stability across temperature is critical in phased array antennas, where temperature-driven phase shifts in feed lines cause beam steering errors. The low water absorption (<0.02%) also means the material’s electrical properties don’t change between dry and humid operating conditions, which matters for outdoor wireless infrastructure exposed to weather.