Broadband and Gain-Enhanced Compressed Higher-Order-Mode Dipoles Using Parasitic Elements and Stubs to Modify Currents

A novel tri-mode broadband high-gain dipole with mode compression is proposed in this paper. First, by introducing bend stubs to realize the modification of the forward and reverse currents of the fifth and seventh-order modes, to improve the gain; Secondly, by introducing straight stubs to extend the current path of the seventh-order mode, to shift the seventh-order mode left and to combine with the fifth-order mode; Finally, by introducing parasitic dipoles to further modify the currents and to generate the coupled resonance modes, to enhance the gain and the bandwidth again. Characteristic mode analysis is utilized, and a prototype is fabricated to verify the principle experimentally. The measurement shows that the antenna worked in the 3.25-4.05 GHz band (25.5%) and a high gain of 7.9 ± 0.6 dBi in the desired n-78 (3.3-3.8 GHz) band.