A Longitudinally Compact Yagi–Uda Antenna With a Parasitic Interdigital Strip

A Yagi-Uda antenna with a parasitic interdigital strip is proposed for a compact design. The parasitic strip is positioned between a driven dipole element and a reflecting element to compensate for the phase change, while high gain and good impedance matching is achieved for the proposed antenna with significant longitudinal reduction. The experimental results show that the proposed two-element Yagi-Uda antenna realizes a gain of 5.1 dBi with the spacing of only 0.06λ
₀
, compared to the conventional spacing of 0.21λ
₀
(λ
₀
is the guided wavelength at 1.48 GHz). The overall size of the proposed antenna is 0.57 λ
₀
× 0.12 λ
₀
.