Mechanically scanned leaky-wave antenna based on a topological one-way waveguide

We propose a uniform backfire-to-endfire leaky-wave antenna (LWA) based on a topological one-way waveguide under external bias magnetic field. We systematically analyze the dispersion, showing that the proposed structure supports leaky mode arisen from total internal reflection. By means of tuning frequency or magnetic field, we obtain fixed-bias frequency and fixed-frequency bias LWA with continuous beam scanning from backward, broadside to forward direction. More importantly, we, for the first time, demonstrate that this proposed LWA shows mechanical tunability, allowing us to manipulate the radiation direction from backward, broadside to forward direction by mechanically tuning the air layer thickness. The simulated results show that our system exhibits super low 3dB beam width, high radiation efficiency as well as high antenna gain. Being provided such multiple controlled (especially mechanically) beam scanning manners, the present LWA paves an advanced approach for continuous beam scanning, holding a great potential for applications in modern communication and radar system.     

W波段基片集成波导缝隙阵天线的研究

介绍了一种低成本高效率的W波段4×4基片集成波导(SIW)缝隙阵天线。天线阵为双层结构,上层为辐射层,采用宽边纵向偏移缝隙驻波阵,可以实现高的辐射功率,下层为馈电层,采用SIW串联缝隙馈电方式,减小了传统功分网络带来的传输损耗和实现难度。对天线阵进行了优化设计,采用标准低成本PCB工艺制作了天线阵实物样品并进行测试。测试结果与仿真结果吻合较好,天线阵在94 GHz时,最大增益为16.8 dB,反射系数-30.1 dB,-10 dB带宽为92.6~96 GHz,副瓣电平19.5 dB,天线阵口径效率为83%。     

High gain and circularly polarized substrate integrated waveguide cavity antenna array based on metasurface

Two substrate integrated waveguide (SIW) cavity antenna arrays based on metasurface are proposed in this paper. By rotating the metasurface element, circularly polarized and high gain antennas are achieved respectively. Firstly, multi-mode resonance theory is employed to broaden the bandwidth of the slot antenna. And then, an SIW cavity composed of 4×4 cornercut elements is added on the top of the slot antenna to achieve the circular polarization and improve the front-to-back ratio. Thirdly, the metasurface elements are sequentially rotated and a high gain antenna with 2-dBi enhancement on average in the operation band is obtained. Based on the two antenna units, two 2×2 antenna arrays are designed. The circularly polarized and high gain antenna arrays are both fabricated to verify the correctness. Furthermore, the novel wideband phase shifter is employed in the circularly polarized antenna to obtain an operating bandwidth of 38% (4.05 GHz-5.95 GHz) and AR bandwidth of 24.9% (4.4 GHz-5.65 GHz). The bandwidth of the high gain antenna can reach 42.7% (3.95 GHz-6.1 GHz) and with the gain enhancement of 2 dBi compared with that of the circularly polarized antenna. The gain remains steady in most of operating band within a variation of 1 dBi. It is remarkable that the rotating of the metasurface element has a great influence on the antenna performance, which provides a new explication for the multi-function antenna design.     

A multi-frequency circularly polarized metasurface antenna array based on quarter-mode substrate integrated waveguide for sub-6 applications

A miniaturized multi-frequency circularly polarized array is designed in this paper. The antenna array is composed of three independent sub-arrays employing modified quarter-mode substrate ntegrated aveguide (QMSIW) to achieve three circularly polarized frequency bands. By introducing strip-slot, the impedance bandwidth of the antenna array is broadened while the dimension is decreased by 75% to realize miniaturization. Meanwhile, metasurface causes the impedance bandwidth of the sub-array to be further enhanced. Moreover, the metal vias are employed in the antenna array design to further achieve miniaturization. The antenna array is manufactured and measured to verify the design. Both the measured and simulated results display that the array achieves the impedance bandwidths of 10%, 11.7%, and 14.8% and axial ratio bandwidths of 8.8%, 8.0%, and 8.5% at 2.5, 3.5, and 4.8 GHz, respectively. The gain is stable in the operating band within an uncertainty of 0.7 dBi. The whole dimension is 0.92λ×0.63λ×0.04λ, where λ₀ is the wavelength at the lowest resonant frequency. Furthermore, the simple structure and miniaturization provides great convenience in sub-6 applications.     

基于超材料吸波体的低雷达散射截面波导缝隙阵列天线

提出利用超材料吸波体减缩波导缝隙阵列天线带内雷达散射截面的设计方法. 设计具有超薄(厚度仅为0.01λ, λ为吸波体中心频率对应波长)、无表面损耗层和高吸波率的超材料吸波体, 将其加载到波导缝隙天线E面方向辐射缝隙间的金属表面上, 并与辐射缝隙保持一定的间距. 该加载方式没有破坏天线的口径馈电振幅分布, 并利用超材料吸波体对电磁波的强吸收特性降低了天线阵的结构模式项散射. 仿真和实验结果表明, 加载超材料吸波体后天线阵的反射系数、增益、波瓣宽度保持不变, 在x极化和y极化条件下, 波导缝隙阵列天线的带内雷达散射截面减缩量均在6 dB 以上, 且在-25°-+25°范围内天线雷达散射截面均有明显的减缩, 鼻锥方向减缩超过10 dB. 该研究成果对阵列天线雷达散射截面减缩具有重要的借鉴意义和工程应用价值.     

小型化多层双模基片集成波导平衡带通滤波器

针对平衡滤波器小型化和高选择的应用需求,提出两种新型的多层双模基片集成波导平衡带通滤波器。首先详细分析了基于平衡端口馈电的双模基片集成波导谐振器的特性;然后根据谐振模式分布特性,设计了一种输入输出馈线同时在上层双模谐振器上的四阶平衡带通滤波器,下层双模谐振器通过十字交叉槽线结构与上层谐振器耦合,可以实现三个传输零点;又提出一种输入和输出馈线分别在上层和下层双模谐振器上的四阶平衡带通滤波器,上层和下层谐振器通过一个槽线进行耦合,可以实现两个对称的传输零点。基于提出的两种平衡滤波器结构,分别设计了一个中心频率为10 GHz的平衡带通滤波器,并进行加工和测试。测试和仿真结果一致性较好,表明了该结构可以实现小型化和高选择,并且具有很好的共模抑制特性。     

Single-beam leaky-wave antenna with wide scanning angle and high scanning rate based on spoof surface plasmon polariton

We propose a single-beam leaky-wave antenna (LWA) with a wide-scanning angle and a high-scanning rate based on spoof surface plasmon polariton (SSPP) in this paper. The SSPP transmission line (TL) is etched with periodically arranged circular patches, which converts the slow-wave mode into the fast-wave region for radiation. The proposed LWA is designed, fabricated, and tested. The simulated results imply that the proposed LWA not only achieves a high radiation efficiency of about 81.4%, and a high scanning rate of 12.12, but also has a large scanning angle of 176° over a narrow operation bandwidth of 8.3—9.6 GHz (for |S₁₁|<-10 dB). In addition, the simulated average gain of the LWA can reach as high as 10.9 dBi. The measured scanning angle range is 175° in the operation band of 8.2—9.6 GHz, and the measured average gain is 10.6 dBi. The experimental results are consistent with the simulation, validating its performance. An antenna with high radiation efficiency, wide scanning angle range, and high scanning rate has great potential for application in radar and wireless communication systems.     

新型负耦合结构在基片集成波导滤波器中的应用

针对高性能交叉耦合基片集成波导带通滤波器的应用,提出一种新型负耦合结构,该耦合结构由两个短路耦合线设计实现,并详细分析了其特性,能够实现较弱或较强的负耦合。总结了基于特征多项式的耦合矩阵综合优化方法,并通过两个滤波器的设计进行说明。基于综合得到的两个耦合矩阵,设计了两个中心频率为10 GHz的四阶交叉耦合基片集成波导带通滤波器,第一个滤波器的归一化相对带宽为3%,负耦合结构提供交叉耦合,用于说明该耦合结构提供相对较弱的耦合强度;第二个滤波器的相对带宽为8%,负耦合结构提供主耦合,用于说明该耦合结构提供较强的负耦合强度。为了验证滤波器的实际性能,对这两款滤波器进行了加工和测试。测试和仿真结果一致性较好,表明了该负耦合结构用于高性能交叉耦合基片集成波导滤波器设计的可行性。最后讨论了弱色散交叉耦合对传输零点位置的影响。     

基于宽波束磁电偶极子天线的宽角扫描线性相控阵列

设计并加工了两款基于宽波束磁电偶极子天线单元的宽角扫描线性阵列.首先,通过加载磁偶极子的方法拓展了天线单元的3-dB波束宽度.然后,基于该宽波束天线单元设计了两款具有良好宽角扫描特性的一维阵列天线.实测结果表明,天线单元的E面方向图3-dB波束宽度在9GHz—12 GHz均大于107°,H面方向图3-dB波束宽度在7GHz—12 GHz均大于178°.E面阵列中心单元的有源驻波比在9GHz—13 GHz小于2,相对阻抗带宽为36.36%.H面阵列中心单元的有源驻波比在9.6GHz—12.6 GHz小于2.5,相对阻抗带宽为27.03%.E面阵列在9GHz—12 GHz可实现±70°的有效宽角扫描.H面阵列在9GHz—GHz可实现±90°的有效宽角扫描.与传统的扫描阵列相比,设计的阵列可实现有效宽带宽角扫描,在X波段相控阵雷达方面具有广阔的应用前景.     

Large negative dispersion in dual-concentric-core photonic crystal fiber with hybrid cladding structure based on complete leaky mode coupling

Considering the optical stability of solution, the sugar-solution is infused into the outer core ring of dual-concentric-core photonic crystal fiber (DCCPCF). The influences of structure parameters and solution concentration on the phase and loss matching are comprehensively analyzed. By choosing the appropriate outer core mode to completely couple with the inner core fundamental mode, the large negative dispersion PCF around 1.55 μm is designed, which has the dispersion value of − 39,500 ps/km/nm as well as bandwidth of 7.4 nm and effective mode area of 28.3 μm². The designed PCF with hybrid cladding structure can effectively compensate the positive dispersion of conventional single mode fiber, and suppress the system perturbation caused by a series of nonlinear effects. Considering the mode field mismatching between the DCCPCF and the tapered fiber, the calculated connection loss around 1.55 μm is below 3 dB. In addition, the equivalent propagation constants of two leaky modes are deduced from the coupled-mode theory, and the complete mode coupling case can be well predicted by comparing the real and imaginary parts of propagation constants.