Design of a novel broadband filtering antenna

In this letter, a novel filtering patch antenna with wide bandwidth is proposed. Firstly, a short-circuited SIR feedline is used to to introduce a new resonant frequency point and generate a lower out-of-band radiation null. Then, stacked patches and parasitic patches are introduced to further expand the bandwidth while achieving a upper out-of-band radiation null. At the same time, grooves are made on both sides of the driving patch for impedance matching. Simulation results show that the proposed filtering antenna operates at 3.18 GHz and achieves a peak gain of 8.1 dBi. The relative bandwidth achieves 27% and the suppression is higher than 20.89 dB.