A study of dual-sleeve broadband antenna based on end-loaded technology

This paper proposed a dual-sleeve broadband omnidirectional antenna based on end-loaded technology. The input impedance of the designed antenna is reduced due to the end-loaded technology and the special dual-sleeve structure, which effectively increase the bandwidth of the antenna. The operating frequency of the dual-sleeve broadband antenna based on end-loaded technology ranges from 57 MHz to 103 MHz, where the voltage standing wave ratio (VSWR) is less than 1.5, i.e., the antenna´s relative bandwidth is 57.5% and the impedance bandwidth is 1.81:1, which can´t be obtained by traditional sleeve antenna. Usually, the VSWR of traditional broadband sleeve antenna is 2.5, which means 43% of the voltage will be reflected, to large power, this is a serious problem. Simulation results agree well with the test results, the results also show that the antenna has a gain of more than 2 dB in the setting frequency range and is omnidirectional in the H plane, which makes this new broadband antenna have a promising application.