A Size-Reduced, 15-Element, Planar Yagi Antenna

A size-reduced, 15-element Yagi antenna is presented in a planar shape. T-shaped, top loadings are implemented to reduce the lengths of the individual antenna elements. The Yagi antenna achieves a 45% reduction in the element lengths compared with a traditional, λ/2 full-sized Yagi antenna. The proposed antenna is simulated, and a prototype is built for measurement validation. The -10 dB impedance bandwidth is 70.0 MHz (4.6%), and the measured realized gain is 13.3 dBi. Compared with the full-sized Yagi antenna, the bandwidth of the proposed, size-reduced Yagi antenna is similar. In addition, a minor difference in realized gain in comparison to the full-sized Yagi is observed when more than two parasitic elements are added. This difference in realized gain between the full-sized Yagi and the size-reduced Yagi is then explained by an approximate contribution of 0.2 dB per each added parasitic element. The measurements and simulations are in good agreement.