Design of Novel Printed Filtering Dipole Antennas

A method of designing a printed filtering dipole antenna using codesign of bandpass filter (BPF) and antenna is proposed in this article. The printed dipole antennas consist of two identical arms, which are placed on the opposite sides of the substrate. One arm of the dipole is used to construct the half-wavelength resonator of a typical BPF, and thus filtering and radiation performance can be obtained simultaneously. A third-order filtering dipole antenna is designed and analyzed in detail to demonstrate the codesign method. The measured S-11 of the filtering dipole antenna is less than -11 dB in the range of 0.94-1.094 GHz and the peak gain is 7.8 dBi. To extend this design method, a third-order +/- 45 degrees dual-polarized filtering dipole antenna is designed and measured. The measured S-11 and S-22 of the +/- 45 degrees dual-polarized filtering dipole antenna are both less than -11 dB in the range of 0.94-1.08 GHz. Besides, the isolation between them is higher than 20 dB in the passband. The measured radiation patterns show that the dual-polarized filtering dipole antenna would be a potential candidate for base stations.