Gyrator-based Subwavelength Radiator with Broadband Huygens Radiation Pattern

It is well known that a narrowband Huygens radiation pattern can be achieved by a combination of a short dipole and a small loop whose excitation currents are offset by 90°. Here we show that it is possible to achieve a broadband directional radiation pattern (the bandwidth of more than $1: 1.6$) by including the feeding network based on positive impedance inverter (gyrator). The basic idea was verified by realistic circuit-theory and full-wave simulations.