Choose RO3003 when temperature stability, dimensional control, compact circuit geometry and plated-through-hole reliability are major priorities. Choose RT/duroid 5880 when the design benefits from an extremely low dielectric constant, very low dielectric loss and nearly isotropic behavior.
RO3003 and RT/duroid 5880 have almost the same published dissipation factor, but they produce very different circuit dimensions and thermal behavior.
RO3003 is a ceramic-filled PTFE laminate with a process dielectric constant of 3.00 ± 0.04 and a dissipation factor of 0.0010 at 10 GHz. RT/duroid 5880 is a glass-microfiber-reinforced PTFE composite with a Dk of 2.20 ± 0.02 and a Df of 0.0009 at 10 GHz.
The 0.0001 difference in published Df is small. In many microwave and mmWave designs, the more consequential differences are:
- dielectric constant;
- thermal coefficient of dielectric constant;
- X-, Y- and Z-axis expansion;
- thermal conductivity;
- transmission-line dimensions;
- mechanical handling;
- multilayer registration;
- copper foil and surface roughness.
A useful Rogers PCB manufacturing review should therefore begin with the circuit architecture, temperature range and manufacturing structure—not with the assumption that the material with the lower Df is automatically the better choice.
Two Laminates with Different Circuit Personalities
RO3003 and RT/duroid 5880 are both PTFE-based high-frequency materials, but their reinforcing systems create different strengths.
RO3003 uses ceramic-filled PTFE and is designed for stable electrical and mechanical properties. Rogers lists applications including automotive radar, satellite antennas, cellular power amplifiers, patch antennas and other commercial microwave systems.
RT/duroid 5880 uses randomly oriented glass microfibers within PTFE. This construction supports a low Dk, uniform electrical properties and near-isotropic behavior. Rogers identifies applications including broadband antennas, microstrip and stripline circuits, millimeter-wave systems, radar and point-to-point radio antennas.
Property Snapshot
| Property | RO3003 | RT/duroid 5880 | Practical Meaning |
| Process Dk | 3.00 ± 0.04 | 2.20 ± 0.02 | RT/duroid 5880 creates larger, wider RF structures |
| Df at 10 GHz | 0.0010 | 0.0009 | Both are extremely low-loss materials |
| TCDk | Approximately −3 ppm/°C | Approximately −125 ppm/°C | RO3003 provides much greater Dk stability over temperature |
| X-axis CTE | 17 ppm/°C | 31 ppm/°C | RO3003 is closer to copper expansion |
| Y-axis CTE | 16 ppm/°C | 48 ppm/°C | RO3003 supports tighter in-plane dimensional control |
| Z-axis CTE | 25 ppm/°C | 237 ppm/°C | RO3003 offers a stronger starting point for PTH reliability |
| Thermal conductivity | 0.50 W/m·K | 0.20 W/m·K | RO3003 conducts heat through the laminate more effectively |
| Water absorption | 0.04% | 0.02% | Both have low moisture absorption |
| Peel strength with 1 oz ED copper | 12.7 lb/in | 31.2 lb/in | RT/duroid 5880 has higher published copper peel strength |
| Density | 2.1 g/cm³ | 2.2 g/cm³ | Similar material density |
| PTFE processing required | Yes | Yes | Neither should be treated as ordinary FR-4 |
The table uses published typical values. Final performance depends on material thickness, copper type, test method, fabrication process and the actual circuit construction.
Project Room 1: A 77 GHz Automotive Radar Front End
A 77 GHz radar PCB must maintain stable resonant frequency, phase response and antenna behavior across temperature. The circuit may experience cold starts, under-hood heat, sunlight exposure and repeated thermal cycling.
For this project, RO3003 is often the more natural starting point.
Why RO3003 Fits Temperature-Sensitive Radar
The most important figure is not the slight Df advantage of RT/duroid 5880. It is the difference in TCDk.
RO3003 has a published TCDk close to −3 ppm/°C, while RT/duroid 5880 is approximately −125 ppm/°C. This means RT/duroid 5880’s dielectric constant changes more significantly with temperature. That change can alter electrical length, resonant frequency, phase and impedance-sensitive behavior.
For a temperature-sensitive radar circuit, dielectric stability may be more valuable than the 0.0001 difference in published dissipation factor.
RO3003 also has much lower in-plane expansion. Its X- and Y-axis CTE values are 17 and 16 ppm/°C, compared with 31 and 48 ppm/°C for RT/duroid 5880. Lower in-plane expansion supports more predictable etched geometry, registration and dimensional behavior through thermal processing.
Rogers positions RO3003 for applications up to 77 GHz, including automotive radar and other temperature-sensitive microwave circuits.
The Role of Circuit Size
RO3003’s higher Dk allows electrically equivalent structures to occupy less physical space than the same structures on RT/duroid 5880.
This can benefit:
- compact patch antennas;
- filters;
- couplers;
- impedance transformers;
- matching networks;
- radar front-end modules.
The actual size reduction depends on circuit topology and effective permittivity, but higher-Dk materials generally shorten guided wavelength and reduce resonator dimensions.
When RT/duroid 5880 May Still Be Chosen
RT/duroid 5880 can still be attractive when:
- the radar architecture prioritizes exceptionally low-Dk behavior;
- antenna efficiency and bandwidth outweigh compact size;
- temperature variation is controlled or compensated;
- the circuit uses wide transmission lines;
- the design already has a validated RT/duroid 5880 model.
The decision should come from temperature-aware electromagnetic simulation rather than room-temperature Df alone.
Project Room 2: A Broadband mmWave Antenna or Feed Network
Now consider a broadband antenna, feed network or long microwave transmission path. The priorities change:
- minimum attenuation;
- low dispersion;
- broad operating bandwidth;
- uniform dielectric properties;
- reduced sensitivity to fiber orientation;
- practical conductor width.
For this project, RT/duroid 5880 becomes more compelling.
Why Low Dk Matters
With a Dk of 2.20, RT/duroid 5880 allows wider transmission lines than RO3003 for the same substrate thickness and characteristic impedance.
Wider traces may provide several practical benefits:
- lower conductor resistance;
- less sensitivity to etching variation;
- easier control of narrow impedance features;
- reduced current concentration;
- more convenient connector and launch transitions.
A lower Dk also allows a greater portion of the electromagnetic field to extend outside the dielectric. This can be advantageous for certain antennas and radiation structures, although it can also make the circuit more sensitive to its enclosure and surrounding environment.
Extremely Low Dielectric Loss
RT/duroid 5880 has a published Df of 0.0009 at 10 GHz and is described by Rogers as its lowest-electrical-loss reinforced PTFE material. Its randomly oriented microfibers help maintain Dk uniformity and near-isotropic behavior across the laminate.
RO3003 remains extremely low loss at 0.0010, so the dielectric-loss difference is not dramatic. For short circuits, it may have little effect on system-level performance. For longer transmission paths or highly sensitive passive networks, the accumulated difference may become more relevant.
RT/duroid 5880 should be selected for its complete low-Dk, broadband and isotropic behavior—not merely because 0.0009 is numerically lower than 0.0010.
Copper Can Change the Result
At mmWave frequencies, conductor loss and copper roughness can be as important as laminate Df.
Rogers’ technical guidance for mmWave circuits shows that smooth rolled copper can produce lower insertion loss than rougher standard electrodeposited copper on very-low-loss PTFE laminates. Similar trends apply to both RT/duroid 5880 and RO3003 constructions.
A practical comparison should therefore specify:
- electrodeposited, reverse-treated or rolled copper;
- copper roughness;
- finished copper thickness;
- surface finish;
- transmission-line width;
- substrate thickness.
Comparing RO3003 with smooth copper against RT/duroid 5880 with rough copper would not isolate the dielectric-material difference.
Project Room 3: A Multilayer Microwave Module with Plated Vias
The third project is a multilayer microwave assembly containing:
- buried RF routing;
- plated through-holes;
- ground-via arrays;
- power and control layers;
- multiple lamination cycles;
- lead-free reflow;
- a wide operating-temperature range.
Here, mechanical behavior becomes central.
Why RO3003 Gains an Advantage
RO3003 has a Z-axis CTE of approximately 25 ppm/°C, compared with approximately 237 ppm/°C for RT/duroid 5880.
Through-thickness expansion places strain on copper plating inside vias during assembly and thermal cycling. The final reliability still depends on board thickness, plating quality, hole diameter, aspect ratio and thermal history, but RO3003’s lower Z-axis expansion provides a much stronger mechanical starting point.
Its X- and Y-axis expansion is also close to copper, supporting dimensional stability during etching, baking and lamination. Rogers specifically positions the RO3000 family for reliable stripline and multilayer construction and notes its stable mechanical properties across temperature.
For multilayer boards with demanding registration and plated-through-hole requirements, RO3003 normally offers the safer material platform.
Is RT/duroid 5880 Unsuitable for Multilayers?
No. RT/duroid 5880 can be used in multilayer constructions with suitable thermoplastic or thermoset bonding systems.
However, the fabrication process must account for:
- soft and compressible PTFE;
- higher dimensional movement;
- adhesive-layer electrical properties;
- core support during processing;
- careful drilling and routing;
- suitable PTFE surface activation.
Rogers’ fabrication guidelines identify thermoplastic bonding films for electrically critical RT/duroid multilayers and thermoset systems where adhesive electrical properties are less demanding.
For a high-layer-count module, the laminate should be evaluated together with the bonding film or prepreg. A low-loss core cannot compensate for a poorly selected bonding layer in a field-sensitive region.
What the Dk Difference Changes in the Layout
The change from Dk 3.00 to Dk 2.20 is not a minor material substitution.
Transmission-Line Width
For the same substrate thickness and target impedance, RT/duroid 5880 will generally require wider microstrip conductors.
If the material is changed without redesigning the line:
- characteristic impedance will change;
- launch geometry will no longer match;
- coupling coefficients may shift;
- resonators may detune;
- electrical delay will change.
Filter and Resonator Size
RO3003’s higher Dk usually produces smaller resonators and shorter guided wavelengths. This can support more compact filters, matching networks and phased-array feed structures.
RT/duroid 5880 produces larger structures but may support broader fields and lower conductor loss through wider traces.
Antenna Behavior
For patch antennas and other printed radiators:
- RO3003 can reduce physical element size;
- RT/duroid 5880 can support wider bandwidth and stronger radiation efficiency in some structures;
- substrate thickness and surface-wave behavior must also be considered;
- enclosure, radome and mounting effects may differ.
The material decision must be made at the electromagnetic-structure level, not by replacing one Dk value in a generic stackup.
Fabrication Reality: Both Are Specialized PTFE Materials
Neither material should be quoted or processed as though it were ordinary epoxy-glass laminate.
Rogers describes both RO3003 and RT/duroid 5880 as PTFE-based materials that are softer than conventional rigid PCB laminates and susceptible to creasing, scratching and dimensional distortion if handled improperly. Thin cores require flat support and controlled transport during fabrication.
Drilling and Hole Preparation
PTFE materials require tightly controlled drilling to prevent smear, redeposited debris and hole-wall defects.
For RT/duroid 5880, Rogers recommends new carbide drills, conservative tool life and controlled feeds. Drilled PTFE hole walls must be activated before electroless copper or direct metallization; sodium treatment is identified as the preferred method for conventional RT/duroid 5870/5880 metallization.
RO3003 also requires PTFE surface activation before metallization. Rogers allows sodium or plasma treatment depending on the process and notes that plasma is often preferred when desmearing thermosetting adhesive layers in multilayer or hybrid boards.
Surface Preparation
Mechanical scrubbing can distort soft PTFE cores or damage critical copper surfaces. Chemical cleaning and microetching are generally preferred, with support provided for thin panels throughout conveyorized processes.
Multilayer Bonding
RO3003 is compatible with several thermosetting and thermoplastic adhesive systems and is also available in bondply configurations for homogeneous RO3000 multilayer construction.
RT/duroid 5880 multilayers require bonding-film selection based on both process requirements and dielectric performance. Thermoplastic films may preserve lower loss, while conventional thermoset prepregs may be acceptable in less electrically critical regions.
A qualified Rogers microwave PCB fabrication supplier should confirm the core, bonding layer, copper foil, hole-wall treatment and press cycle before the impedance design is finalized.
Which Material Fits Which Application?
| Application | More Likely Starting Point | Main Reason |
| 77/79 GHz automotive radar | RO3003 | Stable Dk over temperature and low in-plane CTE |
| Compact microwave filter | RO3003 | Higher Dk supports smaller resonators |
| Phased-array module across a wide temperature range | RO3003 | Better phase and dimensional stability |
| Thick multilayer RF board | RO3003 | Much lower Z-axis CTE |
| Broadband antenna | RT/duroid 5880 | Low Dk and near-isotropic behavior |
| Long microwave feed network | RT/duroid 5880 | Very low dielectric loss and wider traces |
| Satellite or airborne antenna | Project-specific | Balance temperature stability, loss and mechanical structure |
| Point-to-point radio antenna | RT/duroid 5880 | Established low-Dk broadband material |
| Power amplifier PCB | RO3003 often preferred | Higher thermal conductivity and low CTE |
| Laboratory low-loss microstrip | RT/duroid 5880 | Extremely low loss, provided dimensional control is managed |
These are engineering starting points rather than automatic material assignments.
A Five-Question Selection Test
1. Is temperature-driven frequency or phase drift critical?
Choose RO3003 as the initial candidate because its published TCDk is much closer to zero.
2. Does the circuit require the lowest possible Dk?
Choose RT/duroid 5880 when wide traces, broadband antenna behavior or low field confinement are important.
3. Is the design multilayer with many plated vias?
Prioritize RO3003’s lower Z-axis expansion and stronger dimensional stability.
4. Is every small reduction in dielectric loss valuable?
Model both materials using the actual trace length, copper foil and operating frequency. Do not assume the 0.0001 Df difference controls total insertion loss.
5. Is circuit area tightly constrained?
RO3003’s higher Dk usually supports smaller filters, resonators and antenna elements.
Common Material-Selection Errors
Choosing RT/duroid 5880 Only Because Its Df Is Lower
The difference between 0.0009 and 0.0010 is small. Temperature stability or copper roughness may have a larger effect on final performance.
Choosing RO3003 Only Because It Is Used in Automotive Radar
The application label does not replace system analysis. Some antenna and broadband structures may benefit from RT/duroid 5880’s lower Dk.
Reusing the Same Artwork
RO3003 and RT/duroid 5880 do not have interchangeable transmission-line dimensions. Every impedance-controlled and resonant structure must be recalculated.
Ignoring TCDk
Room-temperature measurements can hide frequency drift that appears across the actual operating-temperature range.
Treating Both PTFE Materials as Mechanically Identical
Their CTE values differ substantially. Registration, via reliability and panel movement should be reviewed separately.
Comparing Df While Ignoring Copper Foil
At mmWave frequencies, rough copper can consume more insertion-loss margin than the small dielectric-loss difference between these laminates.
Using a Generic PTFE Fabrication RFQ
The manufacturer needs the exact material, thickness, copper type, surface activation, bonding system and validation requirements.
What to Include in a Rogers PCB RFQ
Provide:
- Exact laminate candidate and permitted alternatives;
- Operating-frequency range;
- Temperature range;
- Core thickness and tolerance;
- Copper foil type and weight;
- Controlled-impedance structures;
- Maximum insertion-loss target where applicable;
- Single-, double-sided or multilayer construction;
- Bonding film or prepreg requirements;
- Via type, hole diameter and aspect ratio;
- Surface finish;
- Dimensional and registration tolerances;
- Coupon and RF test requirements;
- Prototype and production quantities.
Ask the manufacturer to return:
- proposed production stackup;
- actual available material thickness;
- copper-profile confirmation;
- modelled trace geometry;
- bonding-layer electrical properties;
- hole-wall activation process;
- achievable registration tolerance;
- material traceability;
- any proposed substitutions.
Before releasing the artwork, an early RO3003 and RT/duroid PCB review can identify whether the simulated construction matches the material and process the factory can reproduce.
FAQ
Which is better, RO3003 or RT/duroid 5880?
Neither is universally better. RO3003 offers much stronger temperature and dimensional stability, while RT/duroid 5880 provides a lower Dk and marginally lower published Df.
Which laminate has lower insertion loss?
RT/duroid 5880 has a Df of 0.0009 at 10 GHz, compared with 0.0010 for RO3003. Actual insertion loss also depends on copper roughness, conductor geometry, surface finish and line length.
Is RO3003 suitable for 77 GHz radar PCBs?
Yes. Rogers identifies RO3003 for applications up to 77 GHz and lists automotive radar among its typical uses. Its low TCDk and low in-plane CTE make it attractive for temperature-sensitive radar circuits.
Is RT/duroid 5880 suitable for mmWave PCBs?
Yes. RT/duroid 5880 is used for microwave and millimeter-wave microstrip, stripline, antenna and radar applications. Its low Dk and low dielectric loss are particularly useful in broadband structures.
Why is RT/duroid 5880 Dk lower than RO3003?
RT/duroid 5880 uses a glass-microfiber-reinforced PTFE construction, while RO3003 contains ceramic-filled PTFE. The ceramic filler raises RO3003’s dielectric constant and improves its thermal-mechanical stability.
Which material is better for a multilayer microwave PCB?
RO3003 is generally the stronger starting point because of its low X-, Y- and Z-axis CTE. RT/duroid 5880 can also be used in multilayers but requires careful bonding, registration and PTFE processing.
Can RO3003 replace RT/duroid 5880 without changing the layout?
No. Their Dk values differ significantly, so transmission-line width, resonator length, coupling and antenna dimensions must be recalculated.
Which laminate is better for a broadband antenna?
RT/duroid 5880 is often preferred because its low Dk and isotropic electrical behavior support broadband antenna and feed-network designs. Final performance still depends on substrate thickness and antenna topology.
Does copper roughness matter on both materials?
Yes. Both laminates have extremely low dielectric loss, so conductor loss can represent a substantial part of total attenuation at mmWave frequencies. Smooth or low-profile copper should be evaluated for loss-sensitive designs.
Are RO3003 and RT/duroid 5880 processed like FR-4?
No. Both are PTFE-based laminates requiring controlled handling, drilling and hole-wall activation. The fabricator should have experience with sodium or plasma treatment and soft PTFE material processing.
Conclusion
RO3003 and RT/duroid 5880 are not two versions of the same low-loss laminate.
RT/duroid 5880 offers a very low Dk, extremely low dielectric loss and uniform, nearly isotropic electrical behavior. These characteristics make it attractive for broadband antennas, long microwave feed networks and structures that benefit from wider traces.
RO3003 combines very low loss with much stronger temperature stability, low thermal expansion and better dimensional behavior. It is often the more practical choice for radar, compact resonators, phased-array modules and multilayer assemblies with demanding via reliability.
Choose RT/duroid 5880 when low Dk defines the electromagnetic structure; choose RO3003 when stability defines whether the circuit remains accurate and manufacturable.
For project evaluation, submit the frequency, temperature range, preliminary stackup, copper requirement and RF geometry through the Mars-PCB website so the material and fabrication process can be reviewed together.
