Flexible, Conformal, Electrically Small Yagi Antennas on a Small Conducting Cylinder

A flexible, low-profile, vertically polarized, electrically small antenna (ESA) is presented. By introducing a near-field resonant parasitic (NFRP) element and an interdigital structure in the driven monopole and a C-shaped slot on the reflecting monopole, respectively, a Yagi ESA with end-fire radiating is achieved. The performance characteristics are demonstrated stable when antenna is mounted on conducting cylinders with different radii. A 6-element array prototype was fabricated and measured. The measured results are in agreement with their simulated values. The measured results show that this low-profile (0.035λL) and electrically small (ka=0.82) antenna operates in a frequency range centered at 1.7 GHz, and exhibits a 8.2% impedance bandwidth and a 6.4 dBi peak realized gain.