Comparison of spherical antennas fabricated via conformal printing: Helix, meanderline, and hybrid designs

The design tradeoffs between three spherically conformal electric monopolesthe spherical helix (SH), spherical meanderline (SM), and a hybrid designare explored through both simulation and measurement. We show that the SH is efficient, but can be difficult to impedance match without external components. On the other hand, the SM antenna has a widely controllable impedance with slightly increased loss. Thus, a hybrid design is proposed that retains the desirable qualities of both the SH and SM. All three designs are fabricated using a conformal printing technique for comparison. We describe the design tradeoffs and physical insights gained through evaluating the efficiency, $Q$, and matching behavior of these antennas.