低截止频率多倍频程高增益对跖Vivaldi天线北大核心CSCD

针对传统对跖Vivaldi天线的最低截止工作频率较高、增益较低和方向性较差的问题,文中设计了一种新型超宽带对跖Vivaldi天线。融合运用辐射极板开矩形斜槽、加载吸收电阻和寄生矩形贴片等一系列电磁调控措施,扩展了天线的低频工作带宽;采取在天线极板间加载椭圆寄生贴片的技术方式大幅提高了天线的方向性和辐射增益。最后给出了天线的设计流程,从电场分布和表面电流分布的角度揭示了天线的微观工作机制。仿真和实测结果表明:天线的工作频带为0.85~16 GHz(近20倍频程),相对带宽达180%,在3 GHz以上频段增益均超过10 dBi,并且具有较好的端射方向性,在超宽带无线通信、雷达探测、电子对抗和遥感遥测等领域具有广泛的应用前景。

A Multi-octave High-gain Antipodal Vivaldi Antenna with Low Cut-off Frequency

To solve the problems of the lowest cut-off operating frequency being higher, low gain and poor directivity of the traditional antipodal Vivaldi antennas (AVA), an ultra-wideband multi-octave exponentially tapered AVA is proposed in this paper. Through the fusion of a series of electromagnetic control measures, such as notching rectangular slots on the radiating plate and loading absorption resistance and parasitic rectangular patches, the low frequency impedance matching has improved significantly. In addition, parasitic ellipse element is integrated into the center of exponential taper slot without sacrificing size. A substantial increase in directivity and gain of the entire frequency band is achieved. Three design steps of the proposed AVA are employed, and the working principle from the perspective of electric field and surface current distribution is analyzed. The simulated and measured results are in good agreement, which show the bandwidth ranges from 0. 85 to 16 GHz (nearly 20 octave) and the relative bandwidth is about 180%. The realized gain is more than 10 dBi in the operation bandwidth of > 3 GHz. The proposed AVA has the advantages of simple design, easy fabrication and excellent performance, which provides practical significance for the research of ultra-wideband end-fire antenna with low cut-off frequency and high directivity. The design can be widely used in the ultra-wideband wireless communication, radar detection, electronic counter measures and remote sensing applications.