车用毫米波雷达传感器组网技术研究

汽车雷达系统中77GHz毫米波雷达传感器制造成本的大幅度降低，给汽车雷达网络的普及应用奠定了技术基础。简要介绍了发展中的毫米波汽车雷达网络的结构原理、多传感器组网的关键技术以及77GHz汽车雷达网络系统的研究现状。为国内汽车雷达网络的发展和应用提供了借鉴和参考。     

Experimental characterization of coaxial through silicon vias for 3D integration

Coaxial through silicon via (TSV) technology is gaining considerable interest as a 3D packaging solution due to its superior performance compared to the current existing TSV technology. By confining signal propagation within the coaxial TSV shield, signal attenuation from the lossy silicon substrate is eliminated, and unintentional signal coupling is avoided. In this paper, we propose and demonstrate a coaxial TSV 3D fabrication process. Next, the fabricated coaxial TSVs are characterized using s-parameters for high frequency analysis. The s-parameter data indicates the coaxial TSVs confine electromagnetic propagation by extracting the inductance and capacitance of the device. Lastly, we demonstrate the coaxial TSVs reduce signal attenuation and time delay by 35% and 25% respectively compared to the shield-less standard TSV technology. In addition, the coaxial interconnect significantly decreases electromagnetic coupling compared to traditional TSV architectures. The improved signal attenuation and high isolation of the coaxial TSV make it an excellent option for 3D packaging applications expanding into the millimeter wave regime.     

毫米波行波管返波振荡的仿真研究

该文利用HFSS仿真了工作在Ka波段的螺旋线、反绕双螺旋线及耦合腔等慢波系统,通过傅里叶分析得到空间谐波,进而分析和比较了上述慢波系统的返波振荡特性.结果表明:螺旋线慢波系统中出现明显的角向谐波次数和轴向谐波次数不相等的窄问谐波分量,在π模附近,有产生返波振荡的危险:而反绕双螺旋线通过提高基波耦合阻抗及可工作的归一化频率来提高了抑制返波振荡的能力;为了避免返波振荡,耦合腔工作频带的选择应尽可能远离单腔相移为π,2π的频点.     

Tailoring microwave-millimeter-wave dielectric and mechanical properties in CaO–SiO2 glass-ceramics by P2O5 nucleating agent

Glass-ceramics have demonstrated excellent dielectric properties in low-temperature co-fired ceramic (LTCC) technology used in 5G/6G wireless devices. This work studies the mechanical strengths and dielectric properties from microwave to millimeter-wave frequencies in the CaO–SiO₂ glass-ceramics modified via the P₂O₅ as a nucleating agent. The β-wollastonite phase was identified as the primary structure with the preferred ($20\bar{2}$) orientation and parallel plate-like structure in the matrix as P₂O₅ content increases up to 3.5∼5.5 wt%. The P₂O₅ nucleating agent increases degree of long-range crystallization. Elevated mechanical flexural strength of approximately 170 MPa, hardness of ∼720 MPa, and outstanding high-frequency dielectric properties were obtained in the 3.5–5.5 wt% P₂O₅-added CaO–SiO₂ glass-ceramics, due to the enhanced interatomic Si–O bonding in the network. The improved mechanical and dielectric characteristics of the P₂O₅–added CaO–SiO₂ glass-ceramics make the crystallized wollastonite materials for the 5G/6G devices possible.     

Microwave dielectric properties of ultra-low temperature sintered Co1−xMgxMoO4 (x = 0–0.09) ceramics for 5G array antenna applications at millimeter-wave frequency

This study investigates the microwave dielectric properties of pure CoMoO4 ceramics prepared using the conventional solid-state reaction method. Sintering temperatures ranging from 600° to 720°C were employed, and the effects of partial substitution of Mg2 + on these properties, specifically the sintering temperature and microwave dielectric characteristics, were examined. X-ray diffraction patterns revealed the formation of a single solid solution of Co1-xMgxMoO4 (x = 0–0.09) with a monoclinic structure and space group C2/m. Pure CoMoO4 samples sintered at 690 oC displayed dielectric properties of εr = 8.27, Q×f = 64,000 GHz, and τf = –96 ppm/°C. The partial substitution of Co2 + with Mg2 + effectively enhanced the densification of ceramics and reduced their dielectric loss and sintering temperature, which was systematically investigated with respect to dielectric polarization, lattice energy, packing fraction, and bond valence. The Co0.95Mg0.05MoO4 ceramic sintered at 630 oC exhibited excellent dielectric properties with εr = 8.42, Q×f = 71,000 GHz, and τf = –62.27 ppm/°C, and demonstrated good chemical compatibility. Furthermore, this ceramic was employed as a substrate for a 4 × 4 dual-polarized array antenna, indicating significant potential for use in ULTCC applications, particularly in the high-frequency millimeter wave region.