RF Laminate Stock List | Thickness & Copper Options

What Does “RF Laminate Stock” Actually Mean?

RF laminate stock refers to the specific thickness, copper weight, and panel-size combinations that laminate manufacturers and their authorized distributors keep on the shelf for immediate or short-lead shipment. Not every catalog entry is a stock item—Rogers alone lists hundreds of Dk/thickness/copper permutations, but only a fraction ship within two to four weeks. Knowing which constructions are genuinely in stock determines whether your prototype runs in weeks or months.

This guide maps the most commonly stocked RF laminates by family, thickness, and copper cladding, explains the practical impact of choosing a non-stock build, and gives you tools to convert copper weights and plan stackups before you commit to a laminate call-out.

Why Stock Availability Matters for RF Projects

A custom-thickness or non-standard copper laminate order from Rogers or Isola typically adds 8–16 weeks to procurement, sometimes longer for PTFE-based materials that require sintering. For prototyping and low-volume radar or antenna builds, that delay can push an entire program schedule. Designing around a stocked construction—even if it means a slight impedance re-tune—often saves more calendar time than it costs in engineering effort.

Stock items also tend to carry lower minimum-order quantities. A stocked RO4350B panel in 0.508 mm (20 mil) with ½ oz copper can often be bought in single-panel quantities from distributors, while a 0.762 mm (30 mil) panel with 2 oz copper on both sides may require a full-press run.

Commonly Stocked RF Laminates by Family

The table below reflects typical distributor and manufacturer stock patterns. Availability shifts with demand, but these constructions have been reliably stocked over multiple years. Panel sizes are usually 12 × 18 in (305 × 457 mm) or 18 × 24 in (457 × 610 mm) unless noted.

For a deeper breakdown of every available thickness across brands, see the full RF laminate thickness chart. If you need to compare I-Tera MT40 against RO4350B for a mixed digital-RF board, the comparison covers Dk stability, loss tangent, and processing differences side by side.

Copper Cladding: What Ships and What Doesn’t

Most RF laminates are stocked with ½ oz (17.5 µm / 0.7 mil) or 1 oz (35 µm / 1.4 mil) electrodeposited (ED) copper. Rolled-annealed (RA) copper, which offers better fatigue life for flex-rigid builds, is available on some PTFE families but rarely from stock—expect a made-to-order lead time. Two-ounce copper (70 µm / 2.8 mil) is stocked on a few RO4000-series thicknesses; anything heavier than 2 oz is almost always a special order. For builds that call for 3 oz or above, consult the thick copper RF PCB fabrication guide for process limits.

Copper Weight Converter

Enter a copper weight in ounces to see the equivalent thickness in mils and micrometers, or work in reverse. This is useful when reconciling laminate datasheets (which list copper in oz) with stackup tools (which need a dimension).

As a quick sanity check: 1 oz copper equals roughly 35 µm or 1.4 mil. When you stack two 1 oz copper layers on a 10 mil core, the total clad thickness is about 12.8 mil (0.325 mm)—a detail that matters when you feed numbers into a board thickness calculator for a multilayer RF stackup.

Non-Stock Constructions: What to Expect

Requesting a laminate that falls outside the stocked matrix—say, RO4350B in 40 mil (1.016 mm) with 2 oz copper—triggers a press run at the manufacturer. Typical consequences:

• Lead time: 8–16 weeks for thermoset laminates (RO4000, I-Tera); 12–20+ weeks for PTFE (RT/duroid, TLY).
• Minimum order: Often 10–25 panels, depending on the press format.
• Price premium: Expect 1.5–3× the unit cost of a stock panel. The RF laminate price guide breaks down cost drivers in detail.

One practical workaround: bond two thinner stock cores with a bondply (e.g., RO4450F or FEP film for PTFE) to reach a non-standard total dielectric height. This keeps you on stock material and lets the fabricator handle the thickness in lamination. The trade-off is an extra lamination cycle and an additional interface that must be accounted for in the Dk model.

Thickness Tolerance and Its RF Impact

Even when you select a stocked laminate, the as-received thickness can vary. Rogers specifies ±0.5 mil (±13 µm) on a 10 mil core and ±1.5 mil (±38 µm) on a 60 mil core. That tolerance directly shifts the characteristic impedance of a microstrip line—on a 10 mil RO4350B core at 50 Ω, a ±0.5 mil swing in dielectric height moves the impedance roughly ±2–3 Ω. The detailed math and mitigation strategies are covered in the laminate thickness tolerance impact article.

Conformal Coating on Stocked RF Boards

After fabrication, many RF assemblies receive a conformal coating for moisture and contamination protection—especially boards destined for outdoor radar or marine antenna systems. Coating thickness matters at microwave frequencies because any dielectric layer on top of a microstrip trace shifts its effective Dk. Typical conformal coatings (acrylic, silicone, parylene) add 25–75 µm per side; exceeding that range can measurably detune a patch antenna or filter.

Use the tool below to check your target coating thickness and convert between common units.

For example, a 50 µm silicone conformal coat (Dk ≈ 2.7) over a 10 GHz microstrip on RO4003C will lower the resonant frequency of a patch element by roughly 0.5–1.5%, depending on geometry. If your design margin is tight, simulate the coated structure or specify a thinner coat and verify coverage meets IPC-CC-830C requirements.

Panel Sizes and Cut-to-Size Options

Standard stock panels are 12 × 18 in or 18 × 24 in. Some distributors also carry 18 × 12 in and 24 × 18 in half-panels. Rogers offers a few high-runners (RO4350B, RO4003C) in 18 × 48 in production panels for high-volume shops. If your fabricator’s press can only handle 18 × 24 in, ordering a 24 × 36 in panel is wasted material—confirm the working panel size before specifying the laminate order.

How to Specify RF Laminate Stock in Your Fab Drawing

A clear material call-out prevents the fabricator from substituting a non-equivalent laminate. Include all of the following on your fab drawing or stackup notes:

1. Manufacturer and grade: e.g., “Rogers RO4350B” (not just “3.48 Dk laminate”).
2. Core thickness: in both mil and mm, referencing the manufacturer’s nominal (e.g., “20 mil / 0.508 mm nominal”).
3. Copper cladding: weight in oz and type (ED or RA), both sides (e.g., “½ oz ED / ½ oz ED”).
4. Dk value and test frequency: e.g., “Dk = 3.48 ± 0.05 at 10 GHz per Rogers RO4350B datasheet.”
5. Acceptable alternates: If you can tolerate a substitute (e.g., Taconic RF-35 in place of RO4350B), list it explicitly with Dk bounds. If no substitute is acceptable, state “No material substitution permitted.”

Omitting any of these fields opens the door to a procurement mismatch that may not surface until RF test—by which time you have lost weeks.

Stock Strategy: Balancing Design Ideal vs. Supply Reality

The most reliable approach for new RF designs is to start from the stock list, not from a theoretical optimum. Steps:

1. Identify the two or three laminate families that meet your Dk, Df, and thermal requirements.
2. Cross-reference each family’s stocked thicknesses and copper weights against your impedance and stackup targets.
3. Run the impedance calculation on the nearest stock construction; if it lands within your tolerance window (typically ±5 Ω for 50 Ω lines), lock it in.
4. Reserve a non-stock build only when the performance gap cannot be closed by trace-width adjustment or a bonded-core approach.

This workflow avoids the common trap of designing around a 15 mil core that nobody stocks, then scrambling to re-spin the board when procurement quotes a 14-week lead time.

Frequently Asked Questions

Which RF laminate has the shortest lead time?

Rogers RO4350B and RO4003C in standard thicknesses (10, 20, 60 mil) with ½ oz or 1 oz copper are the most widely stocked RF laminates worldwide, typically shipping in 2–4 weeks from authorized distributors.

Can I get 2 oz copper on a stock RF laminate?

Limited options exist—Rogers stocks some RO4350B and RO4003C panels with 2 oz copper in 20 and 60 mil thicknesses. Beyond that, 2 oz cladding is generally a made-to-order item with 8–12 week lead times.

Is PTFE laminate harder to get than thermoset?

Yes. PTFE-based laminates (RT/duroid 5880, Taconic TLY) require sintering and are produced in smaller batches. Stock lead times run 4–6 weeks versus 2–4 weeks for thermoset families like RO4000.

What happens if my fabricator substitutes a different laminate?

Even a laminate with the same nominal Dk can differ in Df, moisture absorption, CTE, and Dk-vs-frequency slope. An unauthorized substitution can shift impedance, increase insertion loss, and change thermal behavior. Always require written approval before any material change.

Do distributors cut RF laminates to custom sizes?

Most authorized distributors sell full panels only. Some offer guillotine cutting for a fee, but tolerances are ±1/16 in (±1.6 mm), which is acceptable for fabrication panelization but not for finished board dimensions.