Quad-band dipole antenna design based on parasitic branching method

Antennas play a key role in communication systems, but antennas in a single frequency band can no longer meet today's needs, so the study of multi-band antennas is very necessary. A novel asymmetric dipole (OFDM) based multi-band antenna is designed for GSM-900, GSM-1800, ISM-2400 and WiMAX-3500 bands. The antenna consists of an asymmetric dipole loaded bowtie patch, metal circular patch, vertical metal ledge, metal post, Balun feed, and fence type patch. Good impedance matching in multiple frequency bands is obtained by adding multiple parasitic structures, and stable radiation characteristics are formed to realize energy harvesting in multiple frequency bands, as well as good directional radiation characteristics in the whole bandwidth of the directional map. The measured results show that the impedance bandwidth of the antenna is 0.93-0.96 GHz, 1.8-1.89 GHz, 2.41-2.46 GHz, 3.36-4 GHz, respectively, and the antenna has good radiation characteristics in the band, and the measured efficiencies are 81.1%, 84.71%, 87.9%, and 83.95%, respectively. The antenna is characterized by miniaturization, high gain, and high design flexibility, and has good application value in wireless communication systems.