RF PCB Materials Comparison: FR4 vs Rogers vs Taconic vs Isola

Choosing the right material for an RF PCB is a design decision that affects electrical performance, manufacturing complexity, and cost. This guide provides a side-by-side comparison of the most common RF laminate families, with practical selection criteria for each.

Master Comparison Table

Property	Standard FR4	Rogers 4003C	Rogers 4350B	Rogers 5880	Taconic TLY-5	Isola I-Tera MT40
Dk @ 10GHz	4.2-4.5	3.38 ±0.05	3.48 ±0.05	2.20 ±0.02	2.20 ±0.02	3.45 ±0.05
Df @ 10GHz	0.020-0.025	0.0027	0.0037	0.0009	0.0009	0.0031
Dk stability (freq)	±5-10%	±2%	±2%	<1%	<1%	±2%
Dk stability (temp)	±2-3%	±0.5%	±0.5%	±0.2%	±0.2%	±0.5%
Resin type	Epoxy/glass	Hydrocarbon ceramic	Hydrocarbon ceramic	PTFE/glass	PTFE/glass	Modified epoxy
Tg (°C)	130-180	>280	>280	—	—	200
CTE z (ppm/°C)	50-70	46	32	237	237	40
UL 94	V-0	HB	V-0	HB	HB	V-0
Processing	Standard	FR4-like	FR4-like	Special (Na etch)	Special (Na etch)	FR4-like
Hybrid compatible	Base	Excellent	Excellent	Difficult	Difficult	Excellent
Relative cost	1x	4-6x	5-7x	15-20x	15-20x	3-5x
Best frequency range	DC-1GHz	1-10GHz	1-10GHz	10-77GHz	10-77GHz	1-15GHz

Material Profiles

Standard FR4

FR4 is the default PCB material — glass-reinforced epoxy with Dk approximately 4.2-4.5 at 1GHz. It is inexpensive, widely available, and easy to manufacture.

RF limitations:

Dk varies with frequency, temperature, and resin content (±5-10%)
Df (0.020-0.025 at 10GHz) causes significant insertion loss above 2GHz
Glass weave creates Dk non-uniformity at fine spatial scales (fiber weave effect)

Acceptable for RF when:

Operating frequency is below 1GHz
Trace lengths are short (<25mm at 5GHz)
Insertion loss budget is generous (loss is not the limiting factor)
Cost is the primary constraint

Not acceptable when:

Antenna elements require Dk accuracy for radiation pattern control
Narrowband filters depend on precise Dk for center frequency
Loss budget is tight at frequencies above 2-3GHz

Rogers 4003C

The workhorse of the RF PCB material world. Thermoset hydrocarbon ceramic laminate with low loss and stable Dk.

Key advantage: Processes like FR4. No sodium etch, no plasma desmear, standard drilling and plating chemistry. This makes it easy to manufacture and ideal for hybrid RF+FR4 stackups.

Key limitation: UL 94 HB flame rating (horizontal burn only). If your product requires V-0, use Rogers 4350B instead.

Available thicknesses: 8, 10, 12, 16, 20, 32, 60 mil (0.203-1.524mm)

Typical applications: Wi-Fi antennas, cellular base station power amplifiers, GPS receivers, 5GHz WLAN modules, radar front-ends below 10GHz.

Rogers 4350B

Very similar to 4003C — same hydrocarbon ceramic resin system with slightly different formulation that achieves UL 94 V-0 flame rating.

Trade-off vs 4003C:

Slightly higher Df (0.0037 vs 0.0027) — approximately 37% more dielectric loss
UL 94 V-0 — required for many commercial and industrial products
Slightly higher Dk (3.48 vs 3.38) — minor impact on trace width calculations

When to choose 4350B over 4003C: When UL 94 V-0 is required by safety certification. If V-0 is not required, 4003C is preferred for its lower loss.

Rogers 5880

PTFE-based laminate for the most demanding high-frequency applications. Ultra-low Df (0.0009) makes it the material of choice for millimeter-wave and microwave circuits above 10GHz.

Key advantages:

Lowest loss in common RF laminates
Extremely stable Dk (2.20 ±0.02, essentially independent of frequency up to 40GHz+)
Suitable for applications up to 77GHz (automotive radar)

Key limitations:

PTFE resin requires special processing (sodium etch, plasma desmear, pre-bake)
Very high CTE z-axis (237 ppm/°C) — creates reliability risk in via-intensive designs
Difficult to combine with FR4 in hybrid stackups (CTE mismatch)
High cost (15-20x standard FR4)
Not suitable for multilayer boards above 4-6 layers (lamination complexity)

Available thicknesses: 5, 10, 15, 20, 25, 31, 62, 125 mil

Typical applications: Automotive radar (24GHz, 77GHz), satellite communication, millimeter-wave antennas, low-noise amplifiers, waveguide transitions.

Taconic TLY-5

PTFE-based laminate comparable to Rogers 5880 in electrical performance. Lower cost in some regions due to different supply chain.

Dk 2.20, Df 0.0009 — essentially identical to Rogers 5880.

Practical difference: Availability and pricing vary by region. Some manufacturers have better supply relationships with Taconic than Rogers, making TLY-5 more readily available. Electrical performance is interchangeable for most applications.

Same processing requirements as Rogers 5880 — sodium etch, plasma desmear, pre-bake.

Isola I-Tera MT40

A modified thermoset laminate that bridges the gap between FR4 and Rogers. Lower loss than FR4, lower cost than Rogers, FR4-compatible processing.

Position in the market: When standard FR4 is too lossy but Rogers cost is not justified. Common in high-speed digital applications (10-25Gbps NRZ) and RF applications below 15GHz where loss requirements are moderate.

Key advantage: UL 94 V-0 flame rating, FR4-like processing, and CTE values close to FR4 (40 ppm/°C z-axis) — making hybrid stackups straightforward with no CTE mismatch concern.

Key limitation: Higher Df than Rogers (0.0031 vs 0.0027 for 4003C) — the loss gap is small but relevant for loss-critical applications above 10GHz.

Selection Decision Tree

Step 1: What is your operating frequency?

Below 1GHz → FR4 is likely sufficient
1-10GHz → Rogers 4003C/4350B or Isola I-Tera
10-40GHz → Rogers 5880 or Taconic TLY-5
40-77GHz+ → Rogers 5880 or specialized millimeter-wave laminates

Step 2: What is your insertion loss budget?

Calculate loss per inch at your frequency using the Df values from the comparison table
Multiply by total trace length
If FR4 loss is within budget → use FR4
If not → select the lowest-cost material that meets your loss requirement

Step 3: Do you need UL 94 V-0?

Yes → Rogers 4350B, Isola I-Tera, or standard FR4 (but not Rogers 4003C or PTFE materials)
No → Rogers 4003C preferred for lower loss

Step 4: Is this a hybrid or all-RF stackup?

Hybrid → thermoset materials preferred (4003C, 4350B, I-Tera)
All-RF → any material, choose based on loss and frequency

Step 5: Budget constraint?

Tight → Isola I-Tera or high-quality FR4 variant (Megtron 4)
Moderate → Rogers 4003C/4350B
Not a constraint → Rogers 5880/Taconic TLY-5

Insertion Loss Comparison

Calculated for 50Ω microstrip at various frequencies (approximate values — actual loss depends on trace geometry and copper roughness):

Frequency	FR4	Rogers 4003C	Rogers 4350B	Rogers 5880	Isola I-Tera
1 GHz	0.04 dB/in	0.02 dB/in	0.02 dB/in	0.01 dB/in	0.02 dB/in
5 GHz	0.22 dB/in	0.05 dB/in	0.07 dB/in	0.02 dB/in	0.06 dB/in
10 GHz	0.50 dB/in	0.12 dB/in	0.15 dB/in	0.05 dB/in	0.13 dB/in
20 GHz	1.10 dB/in	0.28 dB/in	0.35 dB/in	0.10 dB/in	0.30 dB/in
40 GHz	2.40 dB/in	0.65 dB/in	0.80 dB/in	0.22 dB/in	0.70 dB/in

How to use this table: Multiply dB/inch by your total trace length (in inches) to get total insertion loss. A 2-inch trace at 10GHz on FR4 loses 1.0dB; the same trace on Rogers 4003C loses 0.24dB. If that 0.76dB matters in your link budget, the material upgrade is justified.

Processing Requirements Summary

Material	Drilling	Desmear	Surface Prep	Lamination	Pre-Bake
FR4	Mechanical	Chemical (KMnO4)	Standard	Standard	Not required
Rogers 4003C	Mechanical	Chemical	Standard	FR4-compatible	Not required
Rogers 4350B	Mechanical	Chemical	Standard	FR4-compatible	Not required
Rogers 5880	Mechanical + plasma clean	Plasma	Sodium etch	Modified (lower pressure)	Required (105-120°C, 2-4h)
Taconic TLY-5	Mechanical + plasma clean	Plasma	Sodium etch	Modified	Required
Isola I-Tera	Mechanical	Chemical	Standard	FR4-compatible	Not required

The processing column is the most important factor for manufacturer selection. Thermoset materials (4003C, 4350B, I-Tera) can be manufactured by any competent PCB factory. PTFE materials (5880, TLY-5) require specialized equipment and experience.

Hybrid Stackup Compatibility

Material Pair	Compatibility	Notes
4003C + FR4	Excellent	Same bonding chemistry, similar CTE
4350B + FR4	Excellent	Same as 4003C
I-Tera + FR4	Excellent	Nearly identical CTE and processing
5880 + FR4	Difficult	CTE mismatch (237 vs 50-70 ppm/°C), needs specialized bondply
TLY-5 + FR4	Difficult	Same issues as 5880
5880 + 4003C	Moderate	Better CTE match than 5880+FR4, but still requires bondply

Recommendation: Use thermoset RF laminates for hybrid stackups whenever electrical performance allows. Reserve PTFE materials for applications that genuinely require Df <0.001 at 10GHz+.

How Atlas PCB Supports RF Material Selection

Atlas PCB stocks the most common RF laminates and provides engineering support for material selection:

In stock: Rogers 4003C (10/20/30/60 mil), Rogers 4350B (10/20/30/60 mil), Rogers 5880 (10/20/31/62 mil), Taconic TLY-5 (10/20/31/62 mil)
Available on order: Isola I-Tera MT40, Megtron 4/6, and other specialty laminates
Full PTFE processing: Sodium etch, plasma desmear, modified lamination for 5880/TLY-5
Hybrid expertise: Validated hybrid RF+FR4 stackups with appropriate bondply selection
Material CoC: Rogers/Taconic/Isola certificate of conformance with every shipment

Not sure which material is right? Upload your Gerbers and tell us your operating frequency and loss budget. Our engineer will recommend the optimal material and stackup — including hybrid options that balance performance and cost.

Frequently Asked Questions

Which RF PCB material should I use for 5GHz applications?

Rogers 4003C is the standard choice for 5GHz — low loss (Df 0.0027), stable Dk (3.38 ±0.05), and FR4-compatible processing for easy hybrid stackups. Use Rogers 4350B if UL 94 V-0 is required. Isola I-Tera is a lower-cost alternative with slightly higher loss. Standard FR4 can work at 5GHz for very short traces (<25mm) where loss is not critical, but is generally not recommended for antenna elements or matched networks at this frequency.

What is the difference between thermoset and PTFE RF laminates?

Thermoset laminates (Rogers 4003C/4350B, Isola I-Tera) use ceramic-filled hydrocarbon resin that processes identically to FR4 — standard drilling, chemical desmear, standard plating. PTFE laminates (Rogers 5880, Taconic TLY-5) require sodium etch for copper adhesion, plasma desmear, pre-bake for moisture removal, and modified lamination cycles. The processing difference means thermoset materials can be manufactured by any quality PCB factory, while PTFE requires a manufacturer with specific RF material experience and equipment.

Can I mix RF materials with FR4 in one PCB?

Yes, and hybrid stackups are recommended for cost optimization. Thermoset RF materials (4003C, 4350B, I-Tera) bond easily to FR4 and have similar CTE values, making hybrid construction straightforward. PTFE materials (5880, TLY-5) can be combined with FR4 but require specialized bondply at the interface and careful management of CTE mismatch (237 ppm/°C vs 50-70 ppm/°C). A typical hybrid uses RF material on 1-2 signal layers and FR4 for the rest, saving 40-60% versus all-RF construction.