Rogers 3000 Series Models: a Matrix, Not a List

The Rogers 3000 series is usually introduced as a list of part numbers, and that format is why so many drawings carry models that do not exist. The family is not a list: it is a small matrix with a dielectric constant on one axis and the presence or absence of woven glass on the other. Once the matrix is drawn, three things become obvious — which grades are real, why the same Dk appears twice with different losses, and why two of the most-quoted part numbers have no cell to sit in. This article draws the matrix, prices the glass in decibels, and gives the seven grades that actually exist with the thickness and copper each one is stocked in.

Ask what the Rogers 3000 series contains and most descriptions answer with five to seven part numbers in a column. That is a list, and a list cannot answer the only question a designer has: at this dielectric constant, do I want glass in the laminate or not. The series is organised as a matrix, with four Dk levels running across and two mechanical versions running down, and once it is drawn that way the part numbers stop looking arbitrary.

The left column is ceramic-filled PTFE with no woven glass: RO3003, RO3035, RO3006 and RO3010. The right column repeats three of those Dk levels with woven glass added, which Rogers sells under the RO3200 designation: RO3203, RO3206 and RO3210. Three levels have a glass twin, one does not, and there is no RO3035 equivalent. That is the whole family — plus one product that is not a laminate at all, RO3001, which is the bond ply used to join them.

Two consequences follow immediately. First, under the two most-quoted Dk values — 3.0 and 6.15 — there are two different materials with the same geometry and different losses, so “Dk 3.0” on a drawing does not identify a laminate. Second, the widely repeated part numbers RO3002 and RO3015 have no cell in the matrix: there is no 3.0 Dk grade with different filler, and no 15.2 Dk grade at all. A family that is a matrix is easy to verify; a family that is a list is not, which is why the errors persist.

Seven laminates, four Dk levels, one bond ply. The Df column is the price of the glass, and the CTE column is what the glass buys.

The penalty shrinks as the Dk rises, which is not intuitive until the mechanism is clear: the glass is a fixed volume fraction, and its contribution to loss becomes a smaller share as the ceramic filler’s Dk dominates. At 3.00 the glass adds 60 % to Df; at 10.2 it adds 23 %. If a design needs mechanical stability at high Dk, the cost of getting it is lower than at low Dk — and the reverse is the trap, because RO3203 is the worst deal in the family and RO3003 is the best.

What the glass buys is dimensional stability, and it shows up in three columns at once. Z-axis CTE at 10.2 falls from 16 to 34 — it roughly doubles, which is a cost, not a benefit; the benefit is in modulus, peel strength and the way the laminate behaves through a press cycle.

Read the table as a trade, not a ranking. The glass version is stiffer, holds a better peel strength, drills and registers more predictably on a large panel, and pays for all of it with 23 % more loss, twice the Z expansion and a Dk tolerance that is 67 % wider. The last one is the number that catches designs: ±0.50 on 10.2 is ±4.9 % in Dk, which is ±2.4 % in impedance, and at 10.2 Dk the line is 0.216 mm wide on a 0.254 mm core — where a ±25 µm etch tolerance is another 11.6 % of width. The two errors arrive together. The mechanical case for the glass version is set out in the RO3210 analysis.

Where the glass version genuinely wins is on large panels and thick stacks. A 600 mm panel of unfilled PTFE moves 0.31 mm across a 20 K swing on CTE alone; the woven glass constrains that in-plane movement, and the same constraint is what keeps layer-to-layer registration inside ±0.05 mm after three press cycles. On a 4-layer, 300 mm board the difference is invisible; on a 12-layer, 500 mm board it decides the yield.

Two part numbers circulate in nearly every second-hand description of this family, and neither has a place in the matrix. RO3002 is described as a 3.0 Dk grade with 0.0017 loss; the matrix already has a 3.0 Dk grade, and its loss is 0.0010. RO3015 is described as a 15.2 Dk grade with 0.0030 loss; the highest Dk in the whole RO3000 and RO3200 families is 10.2, and no Rogers laminate is specified at 15.2.

The 15.2 figure has a traceable origin, which is why it keeps returning. It is close to the design Dk of a 10.2 material measured at a low frequency, and it also appears in third-party tables that mix Rogers grades with other suppliers’ high-Dk ceramics. Once the matrix is written down with the four real Dk levels — 3.00, 3.50, 6.15, 10.20 — the number has nowhere to go.

The practical damage is not the wrong data sheet, it is the wrong design. A 15.2 Dk material would give a 25 % shorter wavelength than 10.2 and a line width of about 0.14 mm at 50 Ω on a 0.254 mm core, which is below the etch-limited floor for 1 oz copper. A design optimised for that geometry, then built on 10.2, is 25 % long. The same class of error at the low end — RO3002 at 0.0017 instead of the real 0.0010 — overstates the loss budget by 70 %, which is the direction that costs money rather than the direction that fails test. The family-level verification that these two numbers fail is set out in the RO3000 family overview.

The third error in the circulating list is the most consequential, because RO3001 is a real product with real numbers and therefore looks like a laminate. It is not: it is the thermoplastic bond ply used to join RO3000 cores, specified at Dk 2.94 and Df 0.0021, and it is supplied as a film rather than as a copper-clad sheet.

Treating it as a laminate produces a specific and expensive failure. A stack that puts 3001 in the dielectric column counts its 0.10 mm of thickness as part of h, when in a press it flows into the interface and mostly disappears into the bond line; the real h is the core plus whatever the bond ply leaves behind. The impedance consequence is the same one that appears on every bond-ply error: 0.254 mm of core plus 0.10 mm of bond ply at Dk 3.5 turns a 50 Ω line into 61 Ω if it is counted, and leaves the line at 50 Ω with an unmodelled 0.03–0.05 mm of glue if it is not.

The rule is simple and it belongs on the drawing: bond plies go in the stack-up as bonding layers with a flow specification, never in the dielectric column. On the 3000 series the choice is 3001 film, a low-flow prepreg, or FEP, and the choice interacts with the press window rather than with the impedance target. The full set of consequences for a mixed stack is set out in high-frequency PCB stack-up design.

Every grade in this family is published with a process Dk and a design Dk, and on three of them the two are equal. At 10.2 they are not: the process value is 10.20 and the design value is 11.20 — a 9.8 % gap that will move a matching network further than any tolerance on the purchase order.

The cause is dispersion in the ceramic fill: at 10.2 Dk the filler’s polarisation lags further behind the field, so Dk measured as a circuit at 8–40 GHz sits above the clamped-stripline value at 10 GHz. At 3.00 the same effect is present and negligible. The consequence for a drawing is that the model must state which number it used, and the material call-out must state the tolerance on the process value; written that way, the two rows cannot be confused. The parameter set on the 10.2 grade is worked through in the RO3010 parameter analysis.

Availability distinguishes these grades as much as electrical performance does, and it is the part of a model list that a list never shows. Standard cores and claddings are fixed per grade, and the differences are large enough to decide a stack before any electrical question is asked.

Two rows carry more weight than the rest. RO3003 is the only grade in the family with a rolled-copper option from the standard configuration table, which is why the millimetre-wave work concentrates on it — the reasoning is quantified in RO3000 with rolled copper. And RO3035 has the shortest list of all: three core thicknesses, no glass version, no rolled foil. A design that needs Dk 3.50 and a non-standard thickness is not choosing a grade, it is choosing a custom build.

The width column is the reason the Dk level cannot be chosen late. On a 0.508 mm core the 50 Ω line runs from 1.29 mm at 3.00 down to 0.43 mm at 10.2, a factor of three; the same ±25 µm etch tolerance is 1.9 % of the wide line and 5.8 % of the narrow one. Choosing 10.2 for size is therefore also choosing a process capability, not only a dielectric constant.

Every grade here is ceramic-filled PTFE, so the process is the same regardless of which cell of the matrix is chosen. That uniformity is a real advantage of the family and it is also why the model choice does not change the fabrication plan — the plan is already fixed by the chemistry.

The one place where the matrix changes the process is registration on large panels, and it changes it in favour of the glass grades: a 3203 panel and a 3003 panel have the same dielectric constant and the same geometry, and the 3203 will hold layer-to-layer alignment through three press cycles where the 3003 needs a larger allowance. That is the whole reason RO3200 exists, and it is worth 0.0006 of Df on a 3.00 Dk design and 0.0005 on a 10.2 one.

The description this article replaces lists six grades and gets five of them wrong in a way that a drawing would inherit. Each line below pairs the statement with the published value.

The pattern in the last row is the one worth generalising: descriptions written from a single grade’s data sheet get applied to the whole family. RO3003 has no glass; RO3203 has glass and 60 % more loss. A procurement document that says “RO3000 series, glass-reinforced” is a document that specifies 3203 while the design was done on 3003, and the difference in Df alone is bigger than the difference between 3003 and any competing supplier’s low-loss grade.

With seven grades and four Dk levels, the choice can be reduced to a single question at each level. The table gives the answer, the number that forces it, and the grade to avoid at that level.

One further comparison belongs here because it is the question asked most often at a trade show: 3003 against 3010 is not a quality hierarchy, it is a size-for-tolerance swap. At 10.2 the line is a third as wide, so the same etch tolerance costs three times as much impedance accuracy, and the same electrical length occupies 43 % less board area. The two together are compared in RO3010 against RO3003, and the 3.00 end is introduced in the RO3003 introduction.

Because four Dk levels and seven grades share one process, most of the risk in a 3000 series order sits in the description rather than in the material. Six lines close it: the grade as a full part number with the RO32xx or RO30xx prefix; the Dk as a process value with its tolerance, plus a separate line saying which design Dk the model used; Df with the test frequency, since 0.0010 at 10 GHz and 0.0013 at 2 GHz are both true of RO3003; the core thickness in millimetres quoted as core and not as finished dielectric; the cladding, naming rolled foil explicitly when it is wanted, because only RO3003 offers it from the standard table; and the bond ply by name, with the note that it is a bonding layer and does not count towards h.

XCE PCB builds across the whole matrix — 2 to 72 layers, impedance to ±10 % on coupons cut from the panel centre and edge, panels to 600×1200 mm, PTFE hole activation in-house, samples in as fast as 24 hours, inspected to IPC-A-600G and IPC-6015. Send the stack-up for a quote or WhatsApp +86 180 3818 8537.

The Rogers 3000 series is four Dk levels — 3.00, 3.50, 6.15 and 10.20 — with three of them available in a glass-reinforced twin under the RO3200 designation, plus RO3001 as the bond ply that joins them. That is seven laminates and one film, not the five-to-seven part numbers usually quoted, and two of the quoted numbers have no cell in the matrix at all.

The glass twin is a mechanical product, not an electrical upgrade: it doubles Z-axis CTE at 10.2, widens the Dk tolerance from ±0.30 to ±0.50, and adds 23 % to 60 % to Df, with the penalty largest where the Dk is lowest. Buy it when registration on a large stack is the constraint; leave it when loss or Dk tolerance is.

The two numbers that cause the most rework are the 9.8 % gap between process and design Dk on RO3010, and the 0.0010 against 0.0013 habit on RO3003. Both are fixed by writing two lines on a drawing rather than one — and the same discipline applied to the 3000 series with rolled copper is set out in the RO3000 rolled-copper article.