An ultra-wideband cross-band frequency reconfigurable tightly coupled antenna

Abstract

This paper presents a frequency-reconfigurable ultra-wideband tightly coupled antenna array. Different from the traditional ultra-wideband antenna, the tightly coupled antenna is used to expand the antenna bandwidth through the mutual coupling effect between the antenna elements. At the same time, it combines the technical characteristics of the reconfigurable antenna. The antenna can work in both high frequency and low frequency bands and can freely switch the working frequency band. At low frequency, the ultra-wide frequency band of 3.55-6.6GHz is realized by the tight coupling between antenna units. After the coupling part is disconnected, it is equivalent to a dipole antenna with a working frequency band of 14.2-14.6GHz in the high frequency band. The VSWR of the antenna is less than or equal to 2 in the two working frequency bands, and the size of the antenna unit is 0.14λ*0.27λ. By adding a reconfigurable unit (PIN diode) to the antenna arm of the tightly coupled antenna to control the disconnection and connection of the coupling part, switching between high frequency and low frequency working frequency bands is realized. The PIN diode is in a state of series resistance and inductance in the on state, so that the antenna arm is connected to the coupling part to enhance the bandwidth of the low-frequency operating frequency band, and in the off state, it presents a state of large resistance and capacitance in parallel. While changing the operating frequency, the influence of the coupling part on high frequencies is improved.