Non-coplanar strip line-fed wideband dual polarized bowtie antenna

Considering the demand for dual-polarized wideband antenna in communication systems and radar systems, a wideband dual polarized bowtie antenna excited by non-coplanar strip line is proposed in this paper. Dual polarization is realized by two sets of orthogonal bowtie dipoles. The orthogonal bowtie dipoles are fed by a novel balun (a transition from microstrip line into strip line). The tapered microstrip line fed by a coaxial connector is converted into a non-coplanar strip line. Then, the non-coplanar strip line providing symmetrical electric field distribution is a balanced structure which satisfies the balanced feed requirements of bowtie dipoles. Experimental investigations indicate that the impedance bandwidth of 69.23% is available, and the voltage standing wave ratio (VSWR) is below 2 over the frequency range from 8 GHz to 12 GHz. In order to improve the antenna radiation and gain, the dual-polarized antenna is placed in a back cavity. The measure results show that the VSWR is approximately below 3 from 6.8 GHz to 18 GHz, the antenna gain is higher than 0.11 dB from 8 GHz to 12 GHz and the front to back ratio of the coplanar polarization is above 15 dB. The antenna designed can be used in wideband communication systems.