How do you design a PCB antenna?
A PCB antenna is a radiator etched in copper on the circuit board, most often a printed inverted-F, meandered monopole, monopole or loop. It costs essentially nothing to add, but its performance depends on the board’s ground-plane size, the copper-free clearance around it, substrate properties and the enclosure. The fastest route to a working design is to copy a validated vendor reference exactly and retune with a matching network.[1][2][3]
Which printed antenna should you choose?
| Type | Size | Notes |
|---|---|---|
| Printed IFA | ≈ λ/4 arm parallel to ground edge | Self-matched via short; good efficiency |
| Meandered IFA/monopole | Smaller | Narrower bandwidth, more sensitive |
| Straight monopole | λ/4 beyond the ground | Wide bandwidth, needs space |
| Loop | Small | Less sensitive to nearby dielectrics, low efficiency |
Summarized from TI’s Antenna Selection Guide.[4]
What layout rules matter most?
- Place the antenna at a board edge, away from metal, batteries and displays.
- Keep the specified copper-free area on all layers, including under the antenna.
- Provide a ground plane of adequate length; for 2.4 GHz IFAs, roughly a quarter wavelength or more along the feed edge.
- Use a 50 Ω controlled-impedance feed and a pi-matching footprint.
- Stitch ground pours with vias near the antenna feed.[3][4]
How do you verify a PCB antenna?
Measure S11 with a semi-rigid pigtail and a choke in the final enclosure, tune the matching network, then measure efficiency or TRP/TIS in a chamber. Check across production tolerances of substrate thickness and permittivity, especially with FR-4.[1][5]
Frequently asked questions
Can I scale a 2.4 GHz PCB antenna to 868 MHz?
Not simply; ground-plane size and clearance scale too, so use a sub-GHz reference design.
Does FR-4 work for PCB antennas?
Yes at 2.4 GHz and below for most designs, with some loss and tolerance variation.
Why include a matching network if the reference needs none?
Your enclosure and board differ; footprints are cheap insurance.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “AN043: Small Size 2.4 GHz PCB Antenna (SWRA117)”. A. Andersen, Texas Instruments. application note.
- “DN007: 2.4 GHz Inverted F Antenna (SWRU120)”. Texas Instruments. design note.
- “AN1088: Designing with an Inverted-F 2.4 GHz PCB Antenna”. Silicon Labs. application note.
- “Antenna Selection Guide (SWRA161)”. R. Wallace, Texas Instruments. application note.
- “Test Plan for Wireless Device Over-the-Air Performance”. CTIA Certification. current version.