Arlon AD255C PCB Material: Properties, Datasheet & Applications

Picking the right laminate for an antenna or feed network PCB is one of those decisions that looks straightforward until you’re six months into a design and chasing yield problems or unstable PIM performance across a temperature sweep. Arlon AD255C sits in a genuinely useful position in the RF laminate landscape: it’s a third-generation PTFE composite engineered specifically for base station antennas and commercial wireless infrastructure, and it solves the three problems that matter most in that application space — insertion loss, passive intermodulation (PIM), and phase stability across temperature. This guide covers the full picture: what the material is made of, the complete property set, how it compares to its nearest competitors, design and fabrication considerations, and the resources you need to get from datasheet to manufactured board.

What Is Arlon AD255C? Material Origins and Construction

The Arlon brand in RF laminates has a long history. Arlon Electronic Materials developed the AD Series specifically for high-volume commercial wireless applications, targeting a price-performance point between basic PTFE/glass and premium low-loss materials like RT/duroid 5880. Rogers Corporation acquired Arlon in 2015, and the Arlon PCB AD Series now operates under Rogers’ Advanced Electronics Solutions division, retaining the original part numbers and material specifications.

The “AD” designation stands for Antenna Dielectric. The “255” reflects a nominal dielectric constant of 2.55. The “C” suffix is a generational marker — the third generation of the AD Series formulation. Understanding what changed across generations clarifies why the C version is now the standard production choice.

The original AD Series used straight PTFE and woven fiberglass — the “L” generation. Cost reduction combined with a need for better thermal expansion performance led to the “A” generation, which introduced ceramic-filled layers alongside the fiberglass reinforcement. This step reduced both Z-axis CTE and dissipation factor. The “C” generation took that further, increasing the proportion of ceramic-filled layers again. The result is lower dissipation factor and lower Z-axis thermal expansion than either predecessor — two improvements that matter directly for outdoor antenna reliability and insertion loss over the product’s life.

AD255C laminates combine the superior thermal properties of a fluoropolymer resin system with selected ceramic materials and fiberglass reinforcement to yield an RF laminate material with lower loss, lower thermal expansion properties, and lower passive intermodulation (PIM).

The composite construction results from three elements working together. The PTFE fluoropolymer matrix provides the low-loss dielectric foundation — PTFE’s non-polar molecular structure gives it inherently low energy absorption at microwave frequencies. The woven fiberglass reinforcement adds mechanical rigidity and reduces X-Y plane CTE beyond what bare PTFE achieves. The microdispersed ceramic filler, embedded within the PTFE layers, controls Z-axis expansion and — critically — improves thermal stability of the dielectric constant, which is what enables phase stability across temperature cycling.

Arlon AD255C Electrical Properties: Full Datasheet Specifications

Dielectric Constant and Loss Tangent

These are the specs every RF engineer goes to first, and for good reason — they determine trace dimensions, insertion loss, and power efficiency of every transmission line in the design.

Property	Value	Test Frequency	Test Method
Dielectric Constant (Dk)	2.55	10 GHz	IPC TM-650 2.5.5.6c
Dk Tolerance	±0.04	—	Controlled production spec
Dissipation Factor (Df)	0.0014	10 GHz	IPC TM-650 2.5.5.6c
Dissipation Factor (Df)	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. In a corporate feed network for a base station antenna with dozens of splitting and combining elements, Dk variation from board to board translates directly into impedance variation and amplitude/phase inconsistency between antenna elements. A tighter Dk means fewer board-level tuning iterations and more consistent radiation pattern performance in production.

The 0.0014 dissipation factor at 10 GHz is the number that determines how much signal becomes heat over the length of a transmission line. At typical 5G sub-6 GHz frequencies, the actual Df is even lower — closer to 0.0011 at 1 GHz. For an antenna feed board with multiple branching paths, each a few centimeters long, this loss level keeps total insertion loss well below the threshold where it would meaningfully degrade antenna gain or efficiency.

PIM Performance

PIM values as low as −165 dBc are achievable with AD255C using S1 smooth foil. This is one of the headline capabilities of the AD Series materials and a central reason why they dominate base station antenna feed network designs. When two or more high-power carriers are present simultaneously — as they are in every multi-band base station — the PIM products generated by non-linearities in the antenna materials can land inside a receive band and bury weak incoming signals. Ultra-low PIM material like AD255C, combined with appropriate copper foil and assembly practices, keeps these interference products well below the sensitivity floor.

PIM values must be qualified at the design level — the foil type, surface finish, copper weight, and assembly quality all contribute. Rogers specifies typical PIM values based on S1 foil testing at specific thicknesses. Always validate PIM with the exact copper and finish combination planned for production.

Arlon AD255C Mechanical and Thermal Properties

Coefficient of Thermal Expansion

CTE is where the ceramic filler makes its biggest contribution to practical reliability.

Property	Value	Units	Test Method
CTE — X-axis	14–16	ppm/°C	IPC TM-650 2.4.41
CTE — Y-axis	14–16	ppm/°C	IPC TM-650 2.4.41
CTE — Z-axis	~50	ppm/°C	IPC TM-650 2.4.41
Thermal Conductivity	0.42	W/m·K	ASTM C518
Decomposition Temp (Td)	>300°C	—	TGA
Operating Temperature	−55 to +125	°C	—
Water Absorption	<0.03	%	IPC TM-650 2.6.2

The X/Y CTE values of 14–16 ppm/°C closely track copper’s CTE of approximately 17 ppm/°C. That proximity is intentional — it minimizes differential expansion stress between the copper conductors and the substrate during thermal cycling, which protects BGA solder joints and copper trace adhesion in designs that see repeated temperature cycles.

The Z-axis CTE of approximately 50 ppm/°C is significantly lower than standard unfilled PTFE/glass laminates, which typically run 150–200 ppm/°C in the Z-direction. For plated through-holes, Z-axis expansion during solder reflow and field thermal cycling is the primary fatigue driver. That Z-axis CTE of 50 ppm/°C is considerably lower than typical PTFE laminates, which improves plated through-hole reliability significantly. In a panel antenna designed to survive ten or more years of outdoor thermal cycling, this improvement is not marginal — it’s a meaningful reliability differentiator.

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
Flammability	V-0	UL 94

The low water absorption of <0.03% is critical for outdoor applications. Moisture ingress changes the dielectric constant of most laminate materials — PTFE’s near-zero uptake means the electrical properties of AD255C remain stable whether the antenna is operating in a high-humidity coastal installation or a dry continental climate.

Available Configurations: Thickness and Copper Options

Standard Dielectric Thicknesses

The AD Series is currently available in a limited combination of dielectric thickness (0.015″ – 0.062″). Thicker dielectrics can be developed to meet customer requirements.

Thickness (inches)	Thickness (mm)	Common Use Case
0.015″	0.381	Single-layer patch antennas, thin feed networks
0.020″	0.508	Compact antenna arrays
0.030″	0.762	Microstrip feed networks, branch-line couplers
0.060″	1.524	Thicker combiner boards
0.062″	1.575	Standard panel feed boards

Copper Foil Options

Foil Type	Surface Roughness	Best Application
ED (Electrodeposited)	Standard	General microwave circuits
S1 (Special Smooth)	Low profile	PIM-sensitive base station antenna work
Reverse Treated ED	Enhanced peel	High-power amplifier boards
IM (Inverted Mass)	High adhesion	Applications requiring robust foil bonding

For any base station antenna application where PIM specification must be met, the S1 smooth foil is not optional — it’s the required configuration. The surface roughness of the copper-dielectric interface directly affects the micro-scale non-linearities that generate PIM products. Rough foil equals worse PIM. If you’re specifying AD255C for a PIM-critical design and choosing foil type is treated as a minor detail, expect PIM test failures.

Arlon AD255C vs. Competing RF Laminates

Material selection rarely happens in isolation — most engineers are comparing AD255C against several other candidates for the same design slot. Here is how AD255C stacks up against the materials it most commonly competes with:

Material	Dk (10 GHz)	Df (10 GHz)	Z-CTE (ppm/°C)	PIM Rating	Processing	Relative Cost
Arlon AD255C	2.55 ±0.04	0.0014	~50	Excellent (S1 foil)	PTFE process	Medium-Low
Arlon AD250C	2.50 ±0.04	0.0014	~45	Excellent (S1 foil)	PTFE process	Medium-Low
Rogers RO4350B	3.48 ±0.05	0.0037	~46	Moderate	FR4-compatible	Low
Rogers RT/duroid 5880	2.20 ±0.02	0.0009	~237	Low	PTFE process	High
Taconic TLX-8	2.55 ±0.04	0.0019	~181	Moderate	PTFE process	Medium
Isola IS680 AG338	3.38	0.0025	~38	Moderate	Modified FR4	Low

AD255C vs. AD250C: The two materials share identical dissipation factor and the same generational architecture. The difference is the nominal Dk — 2.55 vs. 2.50. On a practical design level, the higher Dk of AD255C produces slightly narrower 50Ω traces and slightly smaller antenna elements for the same frequency target compared to AD250C. This makes AD255C better suited when board real estate is constrained or when antenna element pitch is tight in an array design.

AD255C vs. RO4350B: RO4350B has a significantly higher Dk (3.48) and loss tangent (0.0037 at 10 GHz) compared to AD255C. RO4350B’s major advantage is FR4-compatible processing — no special drilling or through-hole treatment required, which makes it easier to fabricate at shops without PTFE process capability. However, for PIM-critical antenna work, RO4350B’s PIM performance doesn’t match AD255C, and the higher Df means measurably more insertion loss at frequencies above 3 GHz. The choice between them is straightforward: if PIM and loss are the spec drivers, AD255C wins; if FR4-compatible fab and lower cost are the priorities, RO4350B is the choice.

AD255C vs. RT/duroid 5880: RT/duroid 5880 offers lower Dk (2.20) and better Df (0.0009) for the most demanding low-loss applications, but its Z-axis CTE of ~237 ppm/°C is five times higher than AD255C. That makes PTH reliability in duroid 5880 boards a persistent concern over thermal cycling. AD255C is the better choice for antenna boards that need long-term reliability in thermal environments, while duroid 5880 remains the choice for maximum loss performance in laboratory-grade or aerospace designs.

AD255C PCB Design Guidelines

Impedance Calculation and Design Dk

Rogers recommends using a design Dk of 2.60 for impedance calculations. This accounts for manufacturing tolerances and ensures your fabricated boards match simulations more closely than using the nominal 2.55 value. This is a practical and important tip — nominal Dk values are measured under lab conditions, and real fabricated boards land at slightly different effective Dk values depending on copper foil roughness contribution and process variation. Using 2.60 as your design Dk in your electromagnetic solver will produce trace widths that are more likely to hit target impedance in the first prototype run.

For 50Ω microstrip on 0.030″ (0.762 mm) AD255C with 1 oz copper, the trace width will run approximately 2.0–2.2 mm depending on the exact copper weight and surface finish. Always verify with a field solver — simplified closed-form formulas become less reliable at microwave frequencies where trace geometry effects are significant.

Transmission Line Configuration

Microstrip is the most common configuration on AD255C for antenna feed work — it keeps the design simple, allows easy tuning of trace widths, and the dielectric stability of AD255C means the impedance profile holds up across frequency with minimal dispersion. Stripline works well for multilayer feed networks where isolation between adjacent signal layers is needed, but requires careful attention to via transitions and stub effects at higher frequencies.

Grounded coplanar waveguide (GCPW) is worth considering for transitions to connectors and for designs where dielectric thickness variation could affect impedance — GCPW is less sensitive to substrate thickness variation than microstrip, which is useful in higher-tolerance fabrication environments.

PCB Stackup Design for Multilayer AD255C Boards

Multilayer AD255C boards require PTFE-compatible bonding films at layer interfaces. Standard FR4 prepreg is not compatible — it flows and cures differently than PTFE materials and creates adhesion failures at elevated temperatures. Compatible bonding films include FEP (fluorinated ethylene propylene) adhesive films and Rogers’ RO4400 series bonding ply.

Hybrid stackups that combine AD255C RF layers with FR4 dielectric layers for non-RF digital routing are used in some commercial antenna controller boards. These hybrid constructions require close coordination with the PCB manufacturer — the mismatch in lamination temperature requirements between PTFE and FR4 materials means the press cycle must be carefully engineered to avoid delamination at the PTFE/FR4 interface.

Drilling and Through-Hole Preparation

This is where most of the PTFE-specific process knowledge matters. The fluoropolymer matrix in AD255C is soft compared to FR4 — it doesn’t break cleanly under the drill bit but tends to smear and compress at the hole wall if drilling parameters aren’t optimized. Signs of poor drilling include hole wall smearing, bell-mouthed holes, and delamination around the drill entry. Use sharp carbide tooling, run lower spindle speeds than FR4, and apply cooling appropriately.

Plasma treatment (CF4/O2) is preferred before PTH for better adhesion. The fluoropolymer surface of PTFE is inherently non-stick — that’s exactly why it doesn’t accept copper plating without surface activation. Sodium naphthalene chemical etch or CF4/O2 plasma etch both break up the fluorine bonds at the hole wall surface, creating active sites for copper adhesion. Skipping this step or performing it inadequately is the single most common cause of PTH reliability failures on PTFE-based PCBs. A shop that doesn’t have this step in its documented PTFE process flow should not be fabricating AD255C boards.

Assembly and Soldering Considerations

Pre-bake cores at 110–125°C for 30 minutes before lamination to remove any absorbed moisture. While AD255C’s water absorption is very low at <0.03%, pre-baking before lamination is standard practice and eliminates any risk of moisture-related void formation during the lamination press cycle.

Standard lead-free reflow profiles are fully compatible with AD255C — PTFE’s decomposition temperature exceeds 300°C and the material handles solder reflow temperatures without degradation. The low CTE values in X and Y reduce solder joint stress during reflow compared to materials with higher thermal expansion.

Layout Best Practices for Low PIM Performance

Maintain smooth, gradual bends on high-power RF traces. Sharp 90° corners create current crowding at the outer edge of the bend, which generates local non-linearities — one of the contributors to PIM in an otherwise clean design. Use 45° chamfers as a minimum, with curved bends preferable for PIM-critical transmission lines.

Minimize ground via transitions in high-current RF paths. Each via is a small physical discontinuity and a potential PIM source in high-power designs. Route RF signals on a single layer wherever physically possible, and keep the number of layer changes to the absolute minimum required by the design.

Specify tight trace width tolerances with your fab house — ±0.025 mm or better on controlled-impedance lines is appropriate for microwave frequencies. Trace width variation changes the realized impedance, which in high-power antenna applications generates reflection-related PIM contributions in addition to the direct impact on insertion loss.

Typical Applications of Arlon AD255C

Typical applications include base station antenna applications, commercial antennas, digital audio broadcasting (DAB) antennas (satellite radio), and radar manifolds and feed networks.

Base Station Antenna Feed Networks: The primary design target. Corporate feed networks distributing signal from the radio unit to antenna elements in panel antennas rely on AD255C’s combination of low loss, controlled Dk, and ultra-low PIM to maintain radiation pattern performance and system sensitivity across the full antenna aperture.

5G Massive MIMO Antenna Panels: In 5G NR massive MIMO configurations with 32T32R, 64T64R, or larger antenna element counts, the feed network losses must be kept to an absolute minimum because they scale directly into total radiated power and system efficiency. AD255C’s insertion loss performance at sub-6 GHz frequencies makes it the material of choice for these feed structure PCBs.

Radar Manifolds for Automotive ADAS: Radar front-end antennas in 77 GHz ADAS systems benefit from AD255C’s stable dielectric constant over the automotive temperature range (−40°C to +105°C or +125°C) and the low-loss performance that keeps radar sensitivity high.

SDARS and GPS Patch Antennas: Satellite Digital Audio Radio Service (SDARS) systems operating in the 2.3 GHz band and GPS receive antenna patches at 1.575 GHz both benefit from the consistent Dk and low loss of AD255C for accurate element tuning and efficient gain performance.

Commercial Distributed Antenna Systems (DAS): Indoor DAS infrastructure handling multiple carrier frequencies simultaneously in large buildings and venues demands low PIM and consistent performance across a wide frequency range — both core strengths of AD255C.

Useful Technical Resources for Arlon AD255C

Resource	Description	Link
Rogers AD Series Datasheet (AD250C, AD255C, AD300D, AD350A)	Official Rogers datasheet with full property tables	rogerscorp.com
Rogers Laminate Properties Tool	Interactive filter and comparison tool for all Rogers/Arlon materials	Rogers Laminate Tool
Rogers MWI-2010 Microwave Impedance Calculator	Impedance calculator optimized for Rogers materials including AD Series	Rogers Calculator
MatWeb AD255C Data Entry	Full property table with converted engineering units	matweb.com
UL Prospector AD255 Entry	Physical, mechanical, and electrical data in UL’s materials database	ulprospector.com
Legacy Arlon AD Series PDF (via Cirexx)	Original Arlon AD Series technical PDF with Dk vs. frequency graphs	cirexx.com/AD-Series.pdf
Legacy AD255C Datasheet PDF (via Circuiti Stampati)	Direct Arlon AD255C single-material PDF	circuiti-stampati.com/AD255C.pdf
IPC TM-650 Test Methods	Standard test methods referenced throughout the AD255C datasheet	ipc.org/tm-650
Cirtech AD255C Material Page	Technical comparison and interactive product selector	cirtech-electronics.com

Arlon AD255C FAQs

Q1: What is the difference between Arlon AD255C and AD250C?

Both are third-generation PTFE/woven fiberglass/microdispersed ceramic composite materials from the same AD Series family with identical Df values of 0.0014 at 10 GHz. The difference is the nominal dielectric constant: AD250C is Dk = 2.50 ±0.04, while AD255C is Dk = 2.55 ±0.04. The slightly higher Dk of AD255C produces marginally narrower 50Ω traces and slightly more compact antenna elements for the same frequency, which is useful when board space is constrained. AD250C gives slightly wider traces, which can reduce conductor loss. In most practical base station antenna designs either material works, and the choice often comes down to which one the manufacturer has in stock and what the existing tooling traces are optimized for.

Q2: Can Arlon AD255C be processed on standard FR4 equipment?

Partially. AD255C uses the same general PCB fabrication steps — drilling, plating, etching, solder mask — but requires PTFE-specific process parameters at each stage. Drilling requires adjusted speeds and feeds with sharp carbide tooling to avoid hole wall smearing. Through-holes require sodium naphthalene or plasma (CF4/O2) etch surface activation before copper plating to achieve adequate adhesion. Lamination uses PTFE-compatible bonding films rather than standard FR4 prepreg. If a shop has only ever processed FR4, they should not be attempting AD255C boards without process development work first.

Q3: What design Dk should I use for impedance calculations in AD255C?

Rogers recommends using a design Dk of 2.60 rather than the nominal 2.55 for impedance calculations. The nominal value is the measured dielectric constant under standardized lab test conditions. In a real fabricated board, the contribution of copper foil roughness and process variation means the effective Dk seen by a microstrip transmission line is slightly higher than the substrate’s measured Dk. Using 2.60 in your impedance calculator or EM solver will produce trace dimensions that are more likely to land on target impedance in the first prototype run. Using 2.55 tends to produce traces that are slightly narrow, pushing the realized impedance above 50Ω.

Q4: What makes AD255C suitable for outdoor antenna installations?

Three material properties combine to make AD255C reliable in outdoor antenna applications. First, the microdispersed ceramic filler lowers the thermal coefficient of the dielectric constant, meaning Dk (and therefore trace impedance and antenna resonance) drifts very little across the −55°C to +125°C operating temperature range. Second, the Z-axis CTE of ~50 ppm/°C is substantially lower than unfilled PTFE laminates, which reduces PTH barrel fatigue over years of daily thermal cycling. Third, water absorption is below 0.03%, so the material’s electrical properties don’t shift between dry and humid conditions — an important attribute for antennas installed in coastal, tropical, or seasonal environments.

Q5: Is Arlon AD255C still manufactured by Arlon, and where can it be purchased?

Arlon was acquired by Rogers Corporation in 2015. AD255C is currently manufactured and sold by Rogers Corporation under the Arlon AD Series brand name. The material specifications, part numbers, and datasheet are maintained by Rogers. It can be purchased directly through Rogers for large-volume orders or through authorized electronic materials distributors for smaller quantities. Many RF-capable PCB manufacturers maintain stock of AD255C and can source it as part of a turnkey fabrication contract. When purchasing, request a material certificate to verify that the laminate is genuine Rogers/Arlon material meeting the published datasheet specification.