“…Simulated results for radiation efficiency are presented for a type of planar inverted-F antenna (PIFA), introduced in [19], as it is voluminously extended into the 3 rd dimension. The results are validated with three PBF-AM fabricated antennas: flat, partspherical (~66% fill-factor), and full-spherical (~100% fill-factor), using the Wheeler cap method [20][21][22].…”