High-Frequency PCB Material Equivalent Chart

Understanding RF Equivalents

A high frequency PCB material equivalent is an alternative laminate capable of meeting the same RF performance, dimensional, thermal, and manufacturing requirements as the original material after qualification. Similar dielectric constant (Dk) and dissipation factor (Df) values identify candidates, but they do not guarantee direct interchangeability.

This chart compares Isola, Rogers, Taconic, and AGC materials used in antennas, RF filters, power amplifiers, radar, microwave assemblies, and mixed-signal circuits. Panasonic materials are addressed separately where high-speed digital functions overlap with RF construction.

High-frequency and high-speed PCBs are related but different. RF design is usually governed by operating frequency, phase response, resonance, impedance, and transmission loss. High-speed digital design is driven by rise time, data rate, channel loss, skew, and eye-diagram performance.

Material equivalence requires four checks:

1. Electrical compatibility across the actual operating bandwidth.

2. Thermal and mechanical compatibility through fabrication and assembly.

3. Availability of matching laminate, copper, and bonding constructions.

4. Verification of finished-board RF performance and reliability.

A material that passes the first check can still fail the remaining three.

Electrical & Thermal Properties

Dielectric Constant (Dk)

Dk determines wave propagation and influences characteristic impedance, electrical length, and resonant frequency.

At 10 GHz, Rogers RO4003C has a process Dk of 3.38, while RO4350B has a process Dk of 3.48. Their recommended design Dk values are 3.55 and 3.66, respectively.

The distinction matters. Process Dk is associated with a specified laminate test method; design Dk is intended for transmission-line modeling under defined conditions.

For a simple homogeneous-medium approximation, a 1% change in Dk produces approximately a 0.5% change in electrical delay. Real microstrip circuits also depend on air participation, copper thickness, and field distribution.

At 24 GHz, even small changes in electrical length can shift the center frequency of a narrowband filter.

Dissipation Factor (Df)

Df, or loss tangent, quantifies dielectric energy dissipation.

Typical 10 GHz values include:

• Rogers RO4003C: 0.0027.

• Rogers RO4350B: 0.0037.

• Isola Astra MT77: 0.0017.

• Isola I-Tera MT40: 0.0031.

• Taconic TLY-5: 0.0009.

• AGC TSM-DS3: 0.0014.

These figures describe material properties, not finished-circuit insertion loss.

Total RF loss also includes conductor loss, radiation, impedance mismatch, and losses associated with transitions and surface finishes.

For equal geometry and comparable measurement conditions, a lower Df generally reduces dielectric attenuation. The total improvement must be determined through electromagnetic modeling and measurement.

Thermal Expansion (CTE)

CTE describes dimensional expansion with temperature. Z-axis CTE is especially important for plated-hole reliability.

Published values illustrate major differences:

• Rogers RO4003C: 46 ppm/°C.

• Rogers RO4350B: 32 ppm/°C.

• Rogers RT/duroid 5880: 237 ppm/°C.

• AGC TSM-DS3: 23 ppm/°C.

A low-loss PTFE material can therefore require more careful plated-hole and thermal-cycle qualification than a dimensionally stable ceramic-filled alternative.

CTE values must be compared using compatible temperature ranges and test methods.

Moisture Absorption

Moisture affects dielectric stability and can contribute to assembly or environmental reliability risks.

Representative absorption values include RO4003C at 0.04%, RO4350B at 0.05%, RT/duroid 5880 at 0.02%, and AGC TSM-DS3 at 0.07%.

The test method and conditioning period must accompany the percentage. A value measured under one conditioning regime cannot automatically be ranked against another.

High-Frequency Materials & Brands

Rogers RO4000 and RO3000

RO4000 laminates use hydrocarbon-ceramic constructions with fabrication processes closer to conventional epoxy-glass technology than many PTFE laminates.

RO4003C provides Dk 3.38 and Df 0.0027 at 10 GHz. RO4350B provides Dk 3.48 and Df 0.0037 and is rated UL 94 V-0.

The RO3000 series uses ceramic-filled PTFE. RO3003, with nominal Dk around 3.00, targets a different electrical and manufacturing balance.

RO4003C, RO4350B, and RO3003 are not interchangeable simply because all three are RF laminates.

PTFE and Ceramic Composites

PTFE is polytetrafluoroethylene. Teflon is a trademark used for certain fluoropolymer products, rather than a separate generic dielectric chemistry.

PTFE-glass materials such as Taconic TLY-5 and Rogers RT/duroid 5880 have nominal Dk 2.20 and Df 0.0009 at 10 GHz.

Ceramic-filled PTFE materials can offer different dielectric constants, thermal conductivity, and dimensional stability.

The reinforcement system also affects drilling, surface preparation, lamination, and plated-hole reliability.

Isola RF Material Families

Isola is relevant to RF material selection because its portfolio includes both dedicated microwave materials and low-loss thermosets suitable for mixed-signal multilayers.

Astra MT77 has published Dk 3.00 and Df 0.0017 at 10 GHz.

I-Tera MT40 has Dk 3.45 and Df 0.0031 at 10 GHz. Its RF/MW constructions cover a wider Dk range, approximately 3.38–3.75, with Df approximately 0.0028–0.0035.

Tachyon 100G and TerraGreen 400G are additional low-loss materials, but their digital and mixed-signal applications must be distinguished from dedicated microwave substrates.

The exact product grade, dielectric construction, and revision determine whether an Isola material is a suitable RF replacement.

Panasonic Digital Materials

Panasonic MEGTRON laminates are principally associated with high-speed digital interconnects.

They may be used in the digital sections of an RF system or a hybrid PCB. Their inclusion in a material-selection study does not establish them as substitutes for PTFE antenna laminates.

High-Frequency PCB Material Equivalent Chart

The following integrated table groups materials by approximate dielectric behavior and identifies candidate alternatives. Values are nominal, not specification limits.

All Dk and Df values are at 10 GHz unless a different frequency is stated. CTE is Z-axis expansion in ppm/°C. Moisture is percentage absorption.

Group	Manufacturer	Material Grade	Resin System	Dk	Df	Z-CTE	Moisture %	Potential Equivalent	Assessment
A	Rogers	RT/duroid 5880	PTFE / glass microfiber	2.20	0.0009	237	0.02	Taconic TLY-5	Close RF candidate
A	Taconic	TLY-5	PTFE / woven glass	2.20	0.0009	217*	0.02	RT/duroid 5880	Close RF candidate
A	Taconic	TLY-5A	PTFE / woven glass	2.17	0.0009	217*	0.02	TLY-5	Close RF candidate
B	Rogers	RT/duroid 5870	PTFE / glass microfiber	2.33	0.0012	173	0.02	Taconic TLY-3	Close RF candidate
B	Taconic	TLY-3	PTFE / woven glass	2.33	0.0012	217*	0.02	RT/duroid 5870	Close RF candidate
C	Rogers	AD255C	PTFE / woven glass	2.55	0.0013	196	0.03	Taconic TLX-8	Redesign candidate
C	Taconic	TLX-8	PTFE / woven glass	2.55	0.0018	215*	0.02	Rogers AD255C	Redesign candidate
D	Rogers	RO3003	Ceramic-filled PTFE	3.00	0.0010	25	0.04**	AGC NF-30	Close RF candidate
D	AGC	NF-30	Ceramic-filled PTFE	3.00	0.0013	30	0.05	Rogers RO3003	Close RF candidate
D	AGC	TSM-DS3	Ceramic / PTFE / glass	3.00	0.0014	23	0.07	Isola Astra MT77	Redesign candidate
D	AGC	TSM-DS3M	Ceramic / PTFE / glass	2.94	0.0014	23	0.07	Isola Astra MT77	Redesign candidate
D	Isola	Astra MT77	Low-loss thermoset	3.00	0.0017	—	—	AGC TSM-DS3	Redesign candidate
D	Taconic	TLE-95	PTFE / glass	2.95	0.0026	70	0.02	AGC RF-30A	Redesign candidate
D	AGC	RF-30A	Ceramic / PTFE / glass	2.97	0.0020	60	0.05	Taconic TLE-95	Redesign candidate
E	Rogers	RO4533	Hydrocarbon / ceramic	3.30	0.0025	37	0.02	AGC Meteorwave 4000	Redesign candidate
E	AGC	Meteorwave 4000	PPE thermoset	3.30	0.0024	55***	—	Rogers RO4533	Redesign candidate
E	AGC	Meteorwave 8000	PPE thermoset	3.28	0.0016	35***	—	—	No direct equivalent
F	Rogers	RO4003C	Hydrocarbon / ceramic / glass	3.38	0.0027	46	0.04	Isola I-Tera MT40 RF/MW	Redesign candidate
F	Isola	I-Tera MT40 RF/MW	Low-loss thermoset	3.38–3.75	0.0028–0.0035	—	—	RO4003C / RO4350B	Construction-specific
F	Isola	I-Tera MT40	Low-loss thermoset	3.45	0.0031	—	—	Rogers RO4350B	Redesign candidate
F	Rogers	RO4350B	Hydrocarbon / ceramic / glass	3.48	0.0037	32	0.05	Isola I-Tera MT40	Redesign candidate
F	AGC	RF-35TC	Ceramic / PTFE / glass	3.50	0.0020	34	0.05	Taconic RF-35	Conditional RF candidate
F	Taconic	RF-35	Ceramic / PTFE / glass	3.50	0.0018	64	0.02	AGC RF-35TC	Conditional RF candidate
G	Rogers	RO4360G2	Hydrocarbon / ceramic / glass	6.15	0.0038	28	0.08	AGC RF-60TC	Redesign candidate
G	AGC	RF-60TC	Ceramic / PTFE / glass	6.15	0.0020	40	0.03	Rogers RO4360G2	Redesign candidate
H	Isola	Tachyon 100G	PPE-based low-loss system	3.02	0.0021	45****	0.05****	Astra MT77	Digital/RF review required
H	Isola	TerraGreen 400G	Advanced low-loss thermoset	3.15**	0.0017**	—	—	—	No direct equivalent

*The AGC guide reports these Z-CTE figures for the corresponding TLY and TLX products. An older Taconic guide contains different values; the exact current grade and test conditions must be confirmed.

**The RO3003 moisture value is construction- and publication-dependent; verify against the applicable current data sheet.

***Below-Tg Z-CTE in the AGC thermoset guide, not necessarily comparable with full-range laminate CTE.

****Historical comparison data. These values must be verified against the current Isola grade-specific data sheet before procurement or design release.

The RF-35 value originates from an older Taconic guide, where its electrical measurements were made at 1.9 GHz rather than 10 GHz. It is retained as a conditional candidate, not a same-frequency verified equivalent.

Isola Equivalent Material Review

Isola Astra MT77 and AGC TSM-DS3

Both have nominal Dk 3.00. Their Df values are 0.0017 and 0.0014, respectively.

However, Astra MT77 is a thermoset system, while TSM-DS3 is a ceramic-filled PTFE composite. Different bonding, drilling, and thermal-expansion behavior prevent automatic substitution.

Isola I-Tera MT40 and RO4350B

Their nominal process Dk values are 3.45 and 3.48, respectively.

I-Tera MT40 has Df 0.0031; RO4350B has Df 0.0037.

This makes I-Tera MT40 a useful RF screening candidate. The finished circuit still requires redesign checks because RO4350B's recommended design Dk is 3.66.

Isola I-Tera MT40 RF/MW and RO4003C

The RF/MW family includes constructions with Dk near RO4003C's process value of 3.38.

Because the Isola family spans several dielectric constructions, the exact candidate must be selected before comparing electrical performance.

Isola Tachyon 100G and Astra MT77

Both are low-loss materials with nominal Dk near 3.0 in historical data.

They serve different design and manufacturing priorities. Similar Dk does not make a digital multilayer material interchangeable with a dedicated microwave laminate.

Design & Manufacturing Tips

Control Copper Roughness

At 10 GHz, copper skin depth is approximately 0.66 µm. At 30 GHz, it falls to approximately 0.38 µm.

Copper foil profile can therefore become a major contributor to conductor loss.

A production drawing should identify:

1. Copper foil type and finished thickness.

2. Approved roughness or surface-profile specification.

3. Controlled-impedance geometry and tolerance.

4. Surface finish for critical RF features.

5. Coupon requirements for insertion loss and impedance.

For a 100 µm trace, a 10 µm width change represents 10% of nominal width. Its actual impedance effect depends on dielectric thickness and the electromagnetic field distribution.

Use Hybrid Stackups Wisely

A hybrid PCB combines two or more material systems in one multilayer construction.

For example, a six-layer board may use a specialized RF laminate for its top transmission-line structure and a low-loss thermoset for digital control layers.

The factory must verify:

• Bonding material compatibility.

• Lamination temperature and pressure.

• Registration across dissimilar materials.

• Hole-wall preparation and copper adhesion.

• Z-axis expansion through the finished stack.

• Assembly and thermal-cycle reliability.

A hybrid circuit is not automatically cheaper. Specialty bonding films and additional qualification can offset material savings.

Verify Fabrication Capabilities

An illustrative eight-layer RF/HDI PCB might require:

Fabrication item	Engineering target
Layer count	8
HDI construction	1+6+1
Finished thickness	1.60 mm
Fine line/space	75/75 µm
Laser microvia diameter	100 µm
Finished plated hole	0.20 mm
RF impedance	50 Ω ±7%
Differential impedance	100 Ω ±7%
RF validation	S-parameter measurements

These are project requirements, not claims that every listed laminate supports the same fabrication limits.

A factory qualified for 75 µm lines on epoxy-based HDI materials may need separate process validation for PTFE or ceramic-filled constructions.

Factory Qualification Case

Eight-Layer RF Hybrid Board

The following is a representative manufacturing qualification scenario, not an authenticated customer production record.

An eight-layer mixed-signal PCB includes a 10 GHz RF path and digital control circuitry.

The original RF material is RO4350B. The proposed alternative is Isola I-Tera MT40.

The nominal Df changes from 0.0037 to 0.0031, a reduction of approximately 16.2% in loss tangent.

This figure does not establish a corresponding insertion-loss improvement.

Manufacturing Challenges

The engineering review identifies three risks:

1. The original circuit model uses RO4350B design Dk 3.66.

2. The proposed laminate has a different available dielectric construction.

3. The hybrid stackup requires verification of bonding and plated-hole processing.

Qualification Sequence

The factory performs:

1. Exact laminate and prepreg identification.

2. Stackup reconstruction using available thicknesses.

3. RF trace-geometry recalculation.

4. Copper-roughness and insertion-loss modeling.

5. First-article fabrication with dedicated coupons.

6. VNA measurement of insertion and return loss.

7. Microsection inspection and thermal qualification.

The candidate is approved only when measured electrical performance and manufacturing reliability meet the original drawing requirements.

Common Design Errors

Mixing Dk Definitions

RO4003C process Dk 3.38 and design Dk 3.55 are not interchangeable. The same distinction applies to RO4350B.

Comparing Different Frequencies

A Df value measured at 1.9 GHz cannot be ranked directly against one measured at 10 GHz without additional characterization.

Ignoring Material Construction

PTFE-glass, ceramic-filled PTFE, and thermoset materials can have similar Dk but different drilling, lamination, and thermal behavior.

Overlooking Copper Profile

A lower-Df laminate may not achieve the predicted channel improvement when the production copper has greater surface roughness.

Assuming Equivalent Means Drop-In

A material may qualify electrically but fail flame-rating, thickness, bonding, or thermal-reliability requirements.

Omitting RF Testing

Continuity and conventional impedance testing do not verify antenna resonance, filter response, or microwave insertion loss.

Frequently Asked Questions

Q1. What are the differences between FR-4 and Rogers PCBs?

FR-4 is a family of epoxy-glass materials, while Rogers produces multiple specialized RF laminate systems.

RO4003C has nominal Dk 3.38 and Df 0.0027 at 10 GHz. RO4350B has Dk 3.48 and Df 0.0037.

Generic FR-4 cannot be assigned one universal 10 GHz Dk or Df because properties vary by grade and construction.

Q2. What is Rogers material, and what is duroid?

Rogers is a manufacturer of specialty circuit materials. Duroid refers to a family of high-frequency laminate products.

RT/duroid 5880 is a PTFE-based laminate with Dk 2.20 and Df 0.0009 at 10 GHz.

Q3. What is the difference between RO4003C and RO4350B?

RO4003C has process Dk 3.38, design Dk 3.55, and Df 0.0027.

RO4350B has process Dk 3.48, design Dk 3.66, and Df 0.0037.

RO4350B is UL 94 V-0 rated; standard RO4003C is not classified the same way.

Q4. Is PTFE the same as Teflon?

PTFE is the generic polymer polytetrafluoroethylene. Teflon is a trademark associated with certain fluoropolymer products.

PCB laminates can combine PTFE with woven glass, glass microfibers, or ceramic fillers. These constructions have different electrical and manufacturing properties.

Standards and Material Approval

Applicable references include IPC-2221, IPC-2222, IPC-6012, IPC-4101, IPC-4103, and relevant IPC-TM-650 test methods.

IPC-2221 and IPC-2222 address design requirements. IPC-6012 addresses qualification and performance of rigid printed boards. IPC-4101 and IPC-4103 address applicable base-material specifications, while IPC-TM-650 provides defined test methods.

Conclusion

A reliable high-frequency PCB material equivalent chart must compare electrical performance and manufacturing compatibility together.

Isola Astra MT77 and I-Tera MT40 deserve direct consideration alongside Rogers, Taconic, and AGC products. Their similar Dk or Df values can justify substitution studies, but they cannot establish unconditional interchangeability.

The engineering sequence is material screening, construction matching, electromagnetic redesign, fabrication qualification, and measured RF verification.

Only the completed qualification process can establish an approved material replacement.