The Tab antenna is a folded monopole that you miniaturize by forming it into an inverted L with a downward bend at the end (Figure 1). You can solder it perpendicular to a pc board or build it as part of a pc board and place it at a corner. The folded section transforms the 12.5Ω radiation resistance to 50Ω and provides second-harmonic suppression. Third-harmonic suppression comes from an open stub near the base of the antenna.
Detailed NEC-2 modeling explores the sensitivity to changes in the dimensions and optimized harmonic suppression. Because NEC models wire antennas in a vacuum and the Tab antenna is built on FR-4, you must incorporate the dielectric properties of the diel