异面带状线馈电的宽带双极化蝶形天线

针对通信与雷达系统对双极化与宽带天线的要求,提出了一种基于带状线馈电的双极化蝶形天线。通过两对互相正交的蝶形阵子实现了天线的双极化,并采用一种新型的微带线转异面带状线的巴伦给两对正交蝶形阵子平衡馈电。异面带状线为平衡传输线,满足了蝶形阵子对于平衡馈电的要求。在馈电点处由同轴线对微带线馈电,经渐变微带线转化为异面带状线,最后由两组异面带状线给两对正交蝶形阵子馈电。测得该天线实现了69.23%的阻抗带宽,在6.8~14GHz频带内电压驻波比(VSWR)小于2。为使天线单向辐射且改善天线增益,将天线放置于反射吸收腔内。测得天线在6.8~18GHz的频宽内VSWR基本小于3,天线增益在8~12GHz频带内大于0.11dB,天线前后瓣比大于15dB。因此,所提出的双极化蝶形天线可用于宽带通信系统中。

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.