Abstract
In this paper, a filtering patch antenna with flexibly controllable
radiation nulls is presented. The patch antenna is fed by an F-shaped
probe consisting of two arms along the Y-axis and a metal column along
the Z-axis. A broadside radiation null on the lower band is generated by
cross-coupling. Meanwhile, a folded defected ground structure (DGS) is
introduced to generate an upper band radiation null. By adjusting the
parameters of F-probe and DGS, two radiation nulls can be controlled
independently to achieve great out-of-band suppression. For
demonstration, a prototype is fabricated and measured. The simulation
results agree well with the measured ones. A flat in-band realized gain
of filtering antenna is about 7.1dBi. The proposed filtering antenna
operating at 2.33 GHz achieves a wide relative bandwidth of 9.8% and
out-of-band suppression level is more than 24dB.