TPH-1/2 microwave composite dielectric laminate explained by a PCB engineer — properties, Rogers comparison, applications, hybrid-stackup tips, and FAQs.
When I first got handed a spec sheet calling for a TPH-1/2 microwave composite dielectric laminate on a phased-array project, I did what most PCB engineers do: I dug through datasheets, compared it against the Rogers and Taconic stock I had on the shelf, and then called the fab. If you are doing the same thing right now, this article should save you a few hours. I’ll walk through what the TPH-1/2 microwave composite dielectric laminate actually is, where it earns its keep on the bench, how it stacks up against the usual PTFE suspects, and the real-world processing notes that never seem to make it into the marketing brochures.
What Is the TPH-1/2 Microwave Composite Dielectric Laminate?
TPH-1/2 is a composite dielectric copper-clad substrate built from a filled thermoplastic polymer system (ceramic-loaded polyphenylene oxide, PPO-based matrix) rather than the woven-glass PTFE you see in most RF laminates. The “-1” designation means copper on one side; “-2” means copper-clad on both sides. There is also a plain “TPH” stock with no copper at all, which is how it arrives from the mill before cladding.
The substrate is black, the dielectric constant sits at 2.65, and the dissipation factor is tightly controlled to tgδ ≤ 1 × 10⁻³. What the engineering sheet understates is how stable that Dk stays over temperature and frequency — this is the property that actually makes or breaks a microstrip antenna design when your board has to survive a –55 °C cold soak and a 125 °C ambient in the same week.
Made by Taizhou Wangling PCB Insulating Materials Factory, TPH-1/2 sits in the same family as the TP-series (TP, TP-1, TP-2) composite dielectric substrates, but it’s specifically tuned for the low-Dk end of the Wangling range where PTFE-glass and hydrocarbon-ceramic laminates usually compete.
Key Properties of TPH-1/2 Microwave Composite Dielectric Laminate
Here is the property table I keep taped to the side of my monitor:
| Property | Value | Test Condition |
| Dielectric Constant (Dk) | 2.65 | 10 GHz |
| Dissipation Factor (Df / tgδ) | ≤ 1 × 10⁻³ | 10 GHz |
| Operating Temperature | –100 °C to +150 °C | — |
| Peel Strength (Cu to substrate) | > 1.4 N/mm | 1 oz copper |
| Water Absorption | < 0.02% | D48/50 |
| Volume Resistivity | > 10¹⁴ Ω·cm | — |
| Surface Resistivity | > 10¹² Ω | — |
| Specific Gravity | ~1.9–2.1 g/cm³ | — |
| Dielectric Strength | > 30 kV/mm | — |
| Substrate Color | Black | Visual |
| Reinforcement | No fiberglass (filled thermoplastic) | — |
A couple of things are worth calling out because they don’t always show up on competitor comparisons:
The Dk is flat over frequency. You can run the same stackup from 2 GHz through Ku-band without redoing your impedance math for each subrange — the loss climbs only slightly with frequency, which is very different behavior from standard FR-4 or even some ceramic-filled hydrocarbons.
There is no woven glass. That matters for two reasons. First, you don’t fight the “glass-weave effect” when you’re laying out differential pairs — no more chasing mismatched trace pairs because one ran over a bundle and one over a resin pocket. Second, drilling behaves predictably. You’re cutting polymer and ceramic particulate, not shredding E-glass, so hole-wall quality is cleaner on small vias.
Peel strength beats ceramic substrates. Because the copper is bonded to a compliant thermoplastic rather than vacuum-deposited onto a hard ceramic, you get peel numbers that survive real assembly abuse — rework cycles, connector reflow, press-fit stress.
TPH-1/2 vs. Common Alternatives
Most engineers land on TPH-1/2 after pricing Rogers RT/duroid 5880, RO4350B, or a Taconic RF-35. Here is how I read the trade-off:
| Material | Dk | Df @10 GHz | Reinforcement | Relative Cost | Notes |
| TPH-1/2 | 2.65 | ≤ 0.001 | Filled thermoplastic, no glass | $$ | Lighter, easier mechanical processing |
| Rogers RT/duroid 5880 | 2.20 | 0.0009 | PTFE + random glass | $$$$ | Benchmark low-loss |
| Rogers RO4350B | 3.48 | 0.0037 | Hydrocarbon/ceramic + woven glass | $$ | FR-4–like processing |
| Taconic RF-35 | 3.50 | 0.0018 | Ceramic-filled PTFE + woven glass | $$$ | Stable, easy to mill |
| Pure ceramic substrate | 9.8+ | 0.0002 | Alumina | $$$$$ | Brittle, no mechanical rework |
Where TPH-1/2 tends to win is on projects where you need the low loss and temperature stability of a PTFE-class board but you also need to drill, punch, grind, and cut the finished panel without babying it. It machines like a well-behaved thermoplastic, and because the specific gravity is lower than glass-loaded PTFE composites, finished modules come out noticeably lighter — which is why airborne and missile-borne customers keep specifying it.
Applications: Where TPH-1/2 Earns Its Place
After running this material through a few dozen jobs, the application list I’d point a new designer toward looks like this:
Antennas and Antenna Arrays
GPS and BeiDou antennas, microstrip patch antennas, and miniaturized handset antennas are the bread-and-butter use case. The flat Dk over temperature keeps the resonant frequency predictable, and the no-glass construction removes a whole class of Dk anisotropy problems.
Radar and Collision-Avoidance Systems
Aircraft collision avoidance, automotive radar front-ends, weather radar feeds, and ground-penetrating radar all lean on TPH-1/2 where designers want lower loss than standard hydrocarbon laminates without paying full PTFE prices.
Passive Microwave Components
Filters, couplers, power dividers, Wilkinson combiners, and branch-line hybrids. These are thin-trace, high-Q-sensitive parts where Df matters more than any other number on the datasheet.
Satellite and Avionics Electronics
Satellite transceivers, downconverters, and BeiDou satellite system hardware. The wide operating temperature window (–100 °C to +150 °C) and low outgassing make this an aerospace-friendly choice.
Defense and Fuze Electronics
Missile-borne modules, proximity fuzes, electronic countermeasures. Low weight, mechanical robustness, and cold-temperature stability all line up here.
5G and Upcoming 6G Infrastructure
Small-cell antennas, mmWave front-ends, and base-station filter banks — any place you need predictable impedance at 24, 28, 39, or 77 GHz.
TPH-1/2 Processing Notes from the Fab Floor
This is the part of the conversation most datasheets skip. A few practical notes if you’re the one running the board through the shop:
Drilling
Use carbide bits, moderate chipload, standard peck depth. Unlike PTFE-glass, you don’t need to chase thermal damage on small holes. Plasma desmear works well as a pre-plate step, and I’d recommend it for any hole under 0.3 mm because the ceramic filler can leave fine residue on the resin smear that degrades copper adhesion.
Etching
Standard cupric-chloride or alkaline etch chemistry. No sodium-etch requirement before plating, which is one of the pain points on pure-PTFE laminates — if your fab quotes higher for PTFE due to sodium-naphthalene handling, TPH-1/2 typically sidesteps that entirely.
Lamination and Bonding
TPH-1/2 bonds with standard FR-4-compatible prepregs for hybrid stack-ups, which is a huge deal if you’re mixing an RF front-end layer with digital control circuitry on an FR-4 core. Lamination temperatures sit within the normal multilayer press window.
Surface Finishes
HASL, lead-free HASL, ENIG, immersion silver, immersion tin, and OSP are all viable. For 77 GHz automotive radar, I default to ENIG or immersion silver for the skin-effect-friendly surface.
Machining Outline and Cutouts
Routing, punching, and grinding are all fine — the material does not splinter like ceramic and does not smear like soft PTFE. This is one of the sleeper reasons fabs like working with it.
Typical Stackups and Thickness Options
TPH-1/2 is generally available in the following thickness range, with tolerances that get tighter at thinner gauges:
| Thickness | Tolerance | Typical Use |
| 0.25 mm | ±0.04 mm | Thin microstrip, flex-rigid RF |
| 0.50 mm | ±0.05 mm | Patch antennas |
| 0.80 mm | ±0.05 mm | Standard RF front-ends |
| 1.00 mm | ±0.05 mm | General microwave |
| 1.52 mm | ±0.06 mm | Power dividers, filters |
| 2.00 mm | ±0.075 mm | High-power, thick-dielectric patches |
| 3.00 mm | ±0.10 mm | Antenna radomes, low-freq RF |
Copper-weight options typically run 0.5 oz (17 µm), 1 oz (35 µm), and 2 oz (70 µm). Max panel size commonly offered is 400 × 500 mm.
Design Tips for Working with TPH-1/2
A handful of things I wish somebody had told me on the first job:
Trust the Dk at 2.65 across your band. Unlike some hydrocarbon-ceramic laminates where you’ll see a non-trivial Dk shift from 2 GHz to 20 GHz, TPH-1/2 stays basically flat. Your 50 Ω trace at 2 GHz is still 50 Ω at 18 GHz with the same geometry.
Budget a little extra for CTE mismatch. The dielectric is thermoplastic, so Z-axis CTE is higher than a ceramic-filled board. On thick multilayer stacks you’ll want plated-through-hole reliability testing (IST/HATS) if the operating environment cycles hard.
Hybrid smartly. TPH-1/2 on the RF layer + FR-4 on the digital layer with a standard prepreg bond is a very common and cost-effective stackup. Get your fab’s approved prepreg list before you commit.
Test pieces are cheap. The material is less expensive than RT/duroid and considerably less than pure ceramic, so prototype coupons for Dk/Df verification on your exact stackup are genuinely affordable.
Useful Resources for PCB Engineers
A few references I go back to when I’m specifying high-frequency materials:
- Microwaves101 Laminate Comparison Chart — PDF comparison of Dk/Df/CTE across every major microwave laminate: https://www.microwaves101.com/uploads/microwave-laminates-composition-chart.pdf
- IPC-4103 Specification — the industry spec for high-speed/high-frequency laminates. Worth buying through the IPC bookstore if you’re doing this work seriously.
- Taizhou Wangling Insulating Materials Factory — manufacturer site for Wangling TPH/TP series technical data: https://www.wang-ling.com.cn
- Rogers Technology Support — free Dk/Df impedance calculators and application notes: https://www.rogerscorp.com
- Microwave Journal (microwavejournal.com) — ongoing articles on material selection at mmWave.
- RF Cafe (rfcafe.com) — quick-reference calculators for microstrip, stripline, and antenna design.
- IEEE Xplore — searchable database for peer-reviewed papers on thermoplastic composite dielectrics.
For datasheet downloads and hybrid-stackup quoting on TPH-1/2 specifically, a fabricator who regularly handles Wangling materials like Wangling PCB is the fastest route — they’ll have the current revision of the Dk/Df/peel data sheet and will know the approved prepreg list for hybrid builds.
FAQs
Q1: What does the “-1” and “-2” mean in TPH-1/2? TPH is the base substrate without copper. TPH-1 is copper-clad on one side, TPH-2 is copper-clad on both sides. The writing “TPH-1/2” together refers to the product family that includes both single- and double-clad options.
Q2: How does TPH-1/2 compare to Rogers RT/duroid 5880? RT/duroid 5880 has a slightly lower Dk (2.20 vs. 2.65) and slightly lower loss tangent, which makes it the gold standard for lowest-loss microwave work. TPH-1/2 is typically 50–70% less expensive, mechanically easier to machine, and lighter because it has no woven glass. For most microwave antenna and filter work below 40 GHz, TPH-1/2 is a practical substitute. For mmWave above 60 GHz where every 0.001 of Df matters, 5880 is still the benchmark.
Q3: Can TPH-1/2 be used in multilayer hybrid PCBs with FR-4? Yes. This is one of its strengths. TPH-1/2 bonds with standard FR-4-compatible prepregs in the normal multilayer press cycle, so you can run an RF front-end on TPH-1/2 cores and digital control on FR-4 layers in the same stackup. Confirm the specific prepreg with your fab.
Q4: What is the maximum operating frequency for TPH-1/2? The loss tangent stays well-controlled through Ku-band (18 GHz) and is usable up into Ka-band (up to ~40 GHz) for many designs. Above that, you’re into mmWave territory where the loss starts to matter more and a lower-Df material like RT/duroid 5880 or Taconic TLY might be the better choice depending on the link budget.
Q5: Is TPH-1/2 RoHS and halogen-free compliant? Standard production TPH-1/2 from Wangling is RoHS compliant. Halogen-free status should be confirmed against the current revision of the datasheet since formulations occasionally update — ask your fab for the most recent material declaration document before committing to a production build.
Closing Thoughts
If you’re picking a microwave laminate for a real product in 2026, the decision is never purely about Dk and Df. It’s about what the whole board is going to cost, how the fab is going to process it, what the environmental profile looks like, and whether you can hybridize it with the digital side of your design without losing your mind. The TPH-1/2 microwave composite dielectric laminate hits a sweet spot on all four counts for a broad slice of RF work — antennas, radar front-ends, satellite hardware, and passive microwave components especially. It’s not going to displace RT/duroid on the very highest-performance mmWave links, and it’s not trying to. But for the bulk of microwave PCB work where you need PTFE-class stability, thermoplastic machinability, and a reasonable price point, it’s worth having on your shortlist.