Antenna PCB
Plan the radiator, feed and material as one RF structure.
An antenna PCB uses printed conductors as part of an antenna or its feed network. A board-edge wireless antenna, a microstrip patch and a phased-array panel need different ground geometry, dielectric choices and verification.
Use the design tools to establish a starting geometry. Send the released stackup, artwork and RF requirements for a manufacturing quotation.
Which kind of antenna PCB are you designing?
Choose the radiator and its installation before copying a trace shape. The RF feed carries energy to the antenna; it is not automatically the radiating element.
| Structure | Where it fits | What controls the design |
|---|---|---|
| Printed IFA / meander | Compact connected devices and board-edge wireless interfaces. | Ground outline, all-layer keepouts, enclosure and matching. See printed trace antennas. |
| Microstrip patch / array | Directional planar antennas and arrays. | Patch, substrate, backing ground, feed and array coupling. See patch antenna design. |
| Printed dipole / slot | Layouts with an appropriate balanced feed or ground-slot radiator. | Feed/balun or slot excitation, board boundaries and polarization. See PCB dipoles. |
| Loop / NFC | Near-field inductive coupling. | Loop inductance, tuning, metal proximity and IC requirements. A GHz patch calculator is not the right model; see NFC antenna design. |
| FPC or separate antenna board | When the antenna needs a different position from the main electronics. | Cable, connector, mounting and nearby surfaces. See FPC antennas. |
Start a new layout with the PCB antenna design workflow; retain the full reference design, not just the visible copper silhouette.
Printed antenna examples
Original media-library examples show how different printed radiators can look. These photos are not test records or confirmation of a particular manufacturing specification.
Compare the radiator arrangement and feed structure; do not infer gain or laminate grade from appearance.
Patch antenna guide →
The markings identify the photographed examples. They are not a guaranteed operating band for another design.
UWB antenna guide →For the transmission path feeding the antenna, review high-frequency loss, phase and reference continuity. Compare broader RF PCB material and fabrication options before specifying a grade.
Antenna PCB materials: match the construction to the loss and size budget
FR-4 is not automatically unsuitable at 2.4 GHz, and an RF laminate does not automatically make an antenna efficient. A short printed antenna and a long array feed network have different loss and consistency needs. Specify the actual grade, dielectric thickness, copper foil, finish and mask.
| Material choice | When to evaluate it | Dk data and next step |
|---|---|---|
| Specified FR-4 grade | Cost-sensitive short feeds and validated printed antenna references. Check lot/construction variation where resonance is sensitive. | There is no universal FR-4 Dk. The tool’s 4.2 preset is an editable illustration. |
| RO4003C | RF feeds or patches where a controlled material model is useful. | Design Dk 3.55; process Dk 3.38 ± 0.05. |
| RO4350B | RF circuitry and constructions requiring the grade’s specified material properties. | Design Dk 3.66; process Dk 3.48 ± 0.05. |
| RT/duroid 5880 | Low-permittivity PTFE-based designs where loss, dimensions and fabrication route justify it. | Design Dk 2.20. Specify 5880, not 5880LZ. |
| RO4700 antenna-grade family | Antenna panels where the exact grade, construction and application requirements align. | Review the named grade’s datasheet; do not borrow another Rogers grade’s Dk. |
| Hybrid RF laminate + FR-4 | RF layers with separate control circuitry, if the full bonded stack is feasible. | Review bonding, reference planes and dielectric models together. Rogers multilayer stackup planning. |
RO4003C/RO4350B design values above use the datasheet’s 8–40 GHz differential-phase-length method; process values use a different method at 10 GHz. Neither is a universal measured value for every antenna construction. Sources: RO4000 datasheet and RT/duroid datasheet.
Use the Rogers material comparison for the wider material shortlist. Higher Dk can reduce physical dimensions in a simple model, but size, bandwidth, efficiency and manufacturability still need to be assessed together.
Antenna PCB design tools
Start a rectangular patch, size a microstrip feed, evaluate a real-resistance matching section, or interpret return loss. Change tasks without losing your inputs. Material Dk values remain editable and are applied only when you ask.
Antenna PCB Design Workbench
Models, units and a checkable starting point
Free-space wavelength is λ₀ = c/f. A thin rectangular patch starts with W = c/(2f) × √[2/(εr + 1)] and L = c/(2f√εeff) − 2ΔL; the effective permittivity and fringing correction depend on W/h. The classical method is described in Sacramento State’s patch design notes.
At 2.45 GHz, λ₀ is about 122.36 mm and λ₀/4 about 30.59 mm. That quarter-wave value is a scale reference, not the final length of a printed IFA. The patch mode is limited to a thin-substrate planning range; feed point, gain, usable bandwidth and minimum ground size are not guessed.
The feed calculator uses the shared zero-thickness Hammerstad–Jensen microstrip model. Copper thickness, solder mask, grounded coplanar geometry, dispersion and connector launches need a suitable field model. See controlled impedance.
A λ/4 transformer has Zt = √(RsRl) for real positive terminal resistances. The tool calculates its physical length with the effective permittivity of that line width; it does not assume (Dk + 1)/2 or match a general complex antenna impedance.
Antenna PCB cost: separate fabrication from RF qualification
Material and board area are only part of the cost. Hybrid bonding, copper requirements, tolerances, finish, connector assembly and agreed RF testing can change the quotation. Use this optional model to compare stated assumptions; submit files when the construction or test scope becomes specific.
Open the antenna PCB planning budget
Antenna PCB Planning Budget
Design-to-budget transfer copies only the selected material and its sample cost allowances. It does not treat the patch width as board width or the dielectric-to-ground height as finished board thickness.
Ground under the antenna? The answer depends on the structure.
Patch & IFA Ground Geometry
The Silicon Labs inverted-F reference illustrates a radiator keepout and a ground region that participates in antenna behavior. Its rule should not be applied to the backing ground of a microstrip patch. The TI 2.4 GHz IFA reference is another complete geometry to study, including its board context.
For a finished multilayer layout, review every copper layer in the antenna zone. Ground islands, pours and components on a lower layer can change a board-edge radiator even if the top layer looks correct. Continue with PCB antenna placement.
Frequency bands change the task—not just the trace length
Specify your actual operating range and regional requirements. The frequencies below are design examples, not a list of globally permitted channels.
| Design family | Typical engineering question | Useful next page |
|---|---|---|
| Sub-GHz: e.g. 433 / 868 / 915 MHz | Can the product accommodate the radiator and ground, and what does loading do to the efficiency/bandwidth trade-off? | 433 MHz design / LoRa antenna planning |
| 2.4 GHz wireless | Does the complete printed-antenna reference fit this PCB, battery and enclosure? | 2.4 GHz PCB antenna design / BLE antenna layout |
| GNSS: e.g. 1.57542 GHz L1 | Which polarization, ground and receiver installation are required? | GPS patch antennas |
| 5 / 6 GHz wireless and UWB | Does the antenna meet the required bandwidth, group delay or multi-band behavior in the final product? | Wi-Fi antennas / UWB antenna requirements |
| Microwave / mmWave: e.g. 28 GHz | How do dielectric/foil variation, launch geometry, array coupling and fixture reference planes affect the result? | 5G microstrip antenna structures |
One rectangular patch calculation does not synthesize a multi-band radiator, circular polarization or a complete phased array. Those tasks need the appropriate geometry, EM model and measured prototypes.
What must stay consistent from the RF model to the fabricated PCB?
- Release the stackup. Identify the actual grade, dielectric-to-reference heights, copper, bonding layers and approved alternatives.
- Identify critical artwork. Mark radiator edges, feed widths/gaps, ground slots, matching pads and reference-plane boundaries. Agree finished feature requirements instead of assuming nominal Gerber geometry is the measured result.
- Include the real surface. Model solder mask and coatings where used. Some reference antennas include mask; removing it universally is not a sound design rule. Choose finish for the RF and assembly requirements.
- Review transitions and mechanics. Include connector footprints, ground vias, slots, mounting, cables and the antenna-to-enclosure spacing.
- Build and correlate a prototype. Preserve revision and material traceability so tuning changes can be carried into the production build.
For broader manufacturing controls, review PCB equipment and quality assurance. State impedance coupons, cross-sections or other records needed with the order; their availability and acceptance scope must be agreed.
A good S11 result is only one part of antenna validation
| Check | What it establishes | What it does not establish |
|---|---|---|
| Bare-board electrical test | The specified conductor connectivity and isolation. | RF match, gain, pattern or efficiency. |
| Impedance coupon / transmission-line check | Behavior of the agreed coupon or line construction. | Antenna resonance or over-the-air performance. |
| Calibrated S11 / return loss / VSWR | Input match at a defined reference plane across the sweep. | Radiation efficiency, pattern or realized gain. |
| Radiation / OTA measurements | Specified gain, polarization, pattern or efficiency in the measured setup. | Performance after an untested enclosure, cable, mounting or material change. |
At 10 dB return loss, reflected power is 10%, VSWR is about 1.925 and mismatch loss is about 0.458 dB. The other 90% is accepted power; some may still be lost rather than radiated. Keysight’s reflection-measurement guidance explains the measurement context.
Measure prototypes with the intended housing, battery, cable routing and mounting. Agree the fixture, calibration/reference plane, sweep range, sample quantity and acceptance limits before assigning RF tests to a supplier. A low-cost continuity test is not an OTA test package.
Send the RF requirements with the fabrication files
For a manufacturing quotation
- Gerber/ODB++ data, drill files, outline and quantity.
- Released stackup, exact material grade or proposed alternatives.
- Finished copper, critical features, finish and mask/coating requirements.
- Target frequency range, feed impedance and specified tolerances.
- Connector/assembly data if needed; BOM and placement files for assembly.
- Required inspection records, RF tests and target delivery date.
If the design is still being tuned
Send the current geometry, ground outline, enclosure constraints and the problem you need to resolve. Attach simulation or measured S-parameters with their reference plane and revision when available. Mark preliminary inputs clearly.
Send files for an antenna PCB quoteFor populated RF boards, continue with PCB assembly. There is no need to complete the calculator before asking for a quote.
Antenna PCB questions
Can FR-4 be used for an antenna PCB?
Yes, if the actual material, layout and performance requirements support it. Do not choose solely by frequency or assume one FR-4 dielectric constant. A long feed network may justify a different laminate from a short printed antenna.
Does every PCB antenna need a copper keepout underneath?
No. A board-edge IFA and a microstrip patch have different ground requirements. Follow the chosen antenna topology and complete reference design.
Is the calculated microstrip width the antenna width?
No. It is the width of the modeled transmission line for the selected impedance. The radiator geometry is a separate design problem.
Can I copy the dimensions of a 2.4 GHz reference antenna?
Use the reference as a complete construction: layer stack, ground, keepouts, feed, mask and surrounding board. Validate changes in the finished enclosure.
Does the calculator generate a production-ready antenna?
No. It provides initial geometry and interprets idealized models. It does not solve gain, radiation pattern, bandwidth, array coupling or final tuning.
Why do process Dk and design Dk differ?
They come from different characterization methods and conditions. Use the value appropriate to the electromagnetic model, material construction and frequency.
Does low VSWR mean high efficiency?
No. Low reflection means more incident power is accepted. Losses can consume part of that power; efficiency and radiation measurements are separate.
Can the quarter-wave transformer match any antenna?
The tool assumes real positive resistances at one design frequency. A reactive antenna load needs an appropriate matching-network design and frequency response review.
Will changing solder mask or the enclosure affect resonance?
It can. Include nearby dielectric and conductive objects in the model and test the assembled product; do not change coatings or mounting without checking the result.
Are all Rogers materials interchangeable?
No. Grade, dielectric data, foil, thickness and bonding construction matter. Agree substitutions before fabrication.
What is included in the online price?
Only the stated uncalibrated setup and area allowances for a simple two-layer bare board. RF qualification, design, assembly, freight and taxes are excluded.
Can I request a quote without a final antenna design?
Yes. Identify the current revision and unresolved requirements, then send the available files and engineering constraints through Contact.
Manufacturer and engineering references
- TI — 2.4 GHz inverted-F reference design
- Silicon Labs — layout and tuning of a PCB IFA
- Rogers — RO4003C / RO4350B material data
- Rogers — RT/duroid 5870 / 5880 data
- Rogers — RO4725JXR / RO4730G3 antenna-grade data
- Sacramento State — rectangular patch calculation method
- Keysight — reflection measurements
- MathWorks — microstrip patch EM modeling
Datasheet values and reference layouts are engineering inputs; they are not a guarantee of the final antenna’s performance.
