Design of Broadband Antennas Based on the Control of Modes

A design method of broadband antennas is proposed based on the concept of multi-mode filters. The multi-mode broadband filters have been studies many years. In fact, the radiator of a resonant antenna is also a resonator with multiple modes. Therefore, the concept and design method of multi-mode filters can be applied to design broadband resonant antennas. In this paper, a stub-loaded dipole is proposed based on the stub-loaded multi-mode filter and applied to design a dual-polarization broadband antenna for base stations. The simulation and measurement results show that the designed antennas enhance their bandwidths almost without changing their sizes.