RO3003G2 is a distinct construction developed with millimeter-wave automotive radar needs in mind. The comparison with RO3003 should focus on circuit-perceived dielectric behavior, copper interface and manufacturing consistency, not only nominal Dk.
Begin with the complete copper construction
The official family information identifies very-low-profile ED copper as part of the RO3003G2 proposition. RO3003 can be investigated with different copper options. Therefore, a comparison labelled only by resin grade can hide the reason one measured line loses less signal. Record dielectric thickness, foil type, treatment and finished conductor thickness alongside the result.
Do not mix measurement conditions
A design value extracted from a millimeter-wave circuit cannot be compared casually with a lower-frequency process Dk. Open RO3003 and RO3003G2 for their sourced observations, then select a dielectric model appropriate to the operating band. Model loss and phase together: matching attenuation alone does not establish that the propagation model is correct.
Example: a radar-feed transition
If a feed is being moved from an established RO3003 build to a G2 construction, retain the original measured coupon data and simulate the new geometry. Inspect the chip launch, bend radii, etching tolerances and ground-via arrangement. A small material improvement will not necessarily repair a poorly matched transition. Fabricate representative lines of different lengths so the measurement can distinguish propagation from common launch effects.
Qualify manufacturing changes explicitly
Discuss small-hole processing, plating, registration and available foil thickness with the selected fabricator. A product feature supporting advanced fabrication is not evidence that every supplier has qualified that process. Check the proposed finished copper and dielectric spacing in cross-section, and correlate the model at the target band. Use the radar application guide for environmental and system checks. Keep the candidate approval specific to the tested construction, with a change-control rule for foil or material substitutions.
For the change review, make two comparisons if resources permit: unchanged artwork to reveal substitution risk, and re-optimized artwork to judge achievable performance. Label the results clearly. The first asks whether a replacement is safe; the second asks which construction best serves a new design.
Source-aware property comparison
RO3003
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 3.00 ± 0.04 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5 clamped stripline; thickness direction. Source |
| Design dielectric constant | 3 | Typical, 8–40 GHz; differential phase length method. Average across the common constructions in the cited datasheet. Source |
| Dissipation factor | 0.001 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5; thickness direction. Source |
| Thermal conductivity | 0.5 W/(m·K) | Typical; ASTM D5470, 50°C, through-thickness direction. Source |
| Design dielectric constant | 3.16 | Typical; 77 GHz differential phase length method, selector guide footnote 29. Distinct frequency from the 8–40 GHz datasheet Design Dk observation. Source |
| CTE, X axis | 17 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| CTE, Y axis | 16 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| CTE, Z axis | 25 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| Thermal coefficient of dielectric constant | -3 ppm/°C | Typical; -50°C to 150°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); 10 GHz. Source |
| Water absorption | 0.04 % | Typical; D48/50, IPC-TM-650 2.6.2.1. Source |
| Density | 2.1 g/cm³ | Typical; 23°C, ASTM D792. Source |
Typical reported values are not a purchase specification. Process Dk, design Dk and values measured at different frequencies are not interchangeable.
RO3003G2
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 3.00 ± 0.04 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5 clamped stripline; thickness direction. Source |
| Design dielectric constant | 3.07 | Typical; 77 GHz, microstrip differential phase length method. Do not relabel this observation as a 10 GHz measurement. Source |
| Dissipation factor | 0.0011 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5; thickness direction. Source |
| Thermal conductivity | 0.43 W/(m·K) | Typical; ASTM D5470, 50°C, through-thickness direction. Source |
| Thermal coefficient of dielectric constant | -35 ppm/°C | Typical; -50°C to 150°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); 10 GHz. Source |
| Water absorption | 0.06 % | Typical; D48/50, IPC-TM-650 2.6.2.1. Source |
| Density | 2.15 g/cm³ | Typical; 23°C, ASTM D792. Source |
Typical reported values are not a purchase specification. Process Dk, design Dk and values measured at different frequencies are not interchangeable.
Compare RO3003 and RO3003G2 as complete millimeter-wave constructions, including foil, thickness and fabrication variation.