Dual-Polarized Dipole Filtenna With Grid-Shaped Radiator Structure

This letter presents a dual-polarized broadband filtenna (filtering antenna) using grid-shaped transmission line as the radiator arm. It contains a grid-shaped dipole radiator, four impedance-matching patches (IMPs), a metal loop and four C-shaped branches. The grid-shaped transmission line is used to replace the conventional dipole radiator for obtaining an upper band edge high-frequency selectivity radiation null. Four IMPs are added to improve the antenna impedance matching. A metal loop and four C-shaped branches are introduced to generate specific out-of-band radiation nulls to ensure a high-frequency selectivity and high suppression level. As a result, bandpass-type filtering radiation performance and high roll-off-rate response are obtained with three controllable radiation nulls. For demonstration, a prototype of the filtenna is manufactured and measured. The impedance bandwidth of the proposed filtenna is 54.5% (2.83 GHz to 4.95 GHz). The average measured realized gain is 7.8 dBi. Three radiation nulls and better than 19 dB out-of-band suppression levels are realized.