A Sub-6 GHz Dual-Band Dual-Polarized Filtering Antenna

A Sub-6 GHz dual-band dual-polarized filtering antenna is proposed in this letter. It can achieve two wide passbands covering the N77/N79 bands, and realize good filtering response with radiation nulls located at the edges of each passband. By etching the U-shaped slots on the radiators of a basic upstanding half-wavelength dipole antenna, two resonant bands are achieved, together with a radiation null located between two bands. To broaden the bandwidth, a shorter loop-shaped dipole is embedded in the dipole antenna and then another longer loop-shaped dipole is introduced around the dipole antenna, which can create a dual-mode resonance in each band and introduce a radiation null at the higher edge of the higher band (HB) and a radiation null at the lower edge of the lower band (LB). Finally, a parasitic surface is loaded above to improve the impedance matching. To verify the feasibility, the antenna is fabricated and measured, showing that the antenna operates in 3.3 GHz to 4.2 GHz (24%) and 4.8 GHz to 5.4 GHz (11.76%) with an impedance matching level of VSWR < 1.67 and an isolation of 25 dB in LB and HB. In addition, three radiation nulls are generated, achieving a high selectivity in each band.