Dual-Polarized Filtering Antenna Based on Grid-Shaped Radiator

This paper proposes a dual-polarized filtering antenna using the 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% (2.83~4.95 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.