Differential Frequency-Reconfigurable Antenna Based on Dipoles for Sub-6 GHz 5G and WLAN Applications

A new differential frequency-reconfigurable antenna based on dipoles is presented in this letter. The basic structure of the proposed antenna consists of two pairs of vertical arms forming two dipoles, the feeding structure, mode switching structure, and p-i-n diodes. By switching “on” and “off” p-i-n diodes, the antenna can resonate at two states, and thus work centered at 3.5 and 5.5 GHz, respectively. Though the two states correspond to different resonant modes, the effective radiation parts are the same and the mode switching structure will not contribute to the far field for both states. This results in similar radiation patterns for both states. Besides, the proposed antenna is also simple in structure and wide in bandwidth. The measured -10 dB impedance bandwidths are 2.89-4.07 GHz (33%) and 5.1-6.19 GHz (19.8%) for the two states, respectively.