Multiband Antennas Comprising Multiple Frame-Printed Dipoles

In this communication, the design of a multiband antenna consisting of a set of printed frame dipoles is proposed. The frame dipoles of different sizes are nested within each other and are employed as resonators to produce a multiband response. The dual-band antenna operating at 2.4/3.5 GHz is realized by a primary frame dipole having a nested smaller frame dipole. The triband antenna operating at 1.8/2.4/3.5 GHz is composed of three frame dipoles nested within each other. The experimental results show stable radiation patterns similar to those of the traditional strip dipole. The gain of the dual-band antenna is 1.77 dBi at 2.4 GHz and 2.17 dBi at 3.5 GHz, and the gain of the triband antenna is 1.72 dBi at 1.8 GHz, 1.53 dBi at 2.4 GHz, and 1.41 dBi at 3.5 GHz.