Huang Kuang-Hsuan, Chen Yen-Sheng
Department of Electronic Engineering, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan.
Sensors (Basel). 2025 Sep 21;25(18):5904. doi: 10.3390/s25185904.
Radar-based water-level monitoring requires antennas with narrow beams, high gain, and low sidelobes. Existing horn and series-fed microstrip arrays either lack compactness or suffer from frequency-dependent beam deviation that reduces sensing accuracy. This paper presents a 256-element slot-coupled planar microstrip array operating in the K-band for water-level radar. The array combines large-scale integration with slot-coupled feeding, which provides inherent 180° phase correction and stabilizes the main beam across frequency. The fabricated array has overall dimensions of 140 mm × 160 mm × 1.12 mm. Simulated results show a peak gain of 22.8 dBi with beamwidths of 5.2° (E-plane) and 4.2° (H-plane), while beam deviation remains within 0.5° across 25.9-27.0 GHz. In comparison, a series-fed array of identical aperture exhibits up to 7.5° deviation and only 15.8 dBi broadside gain. These results demonstrate that the proposed slot-coupled array provides a compact antenna solution meeting regulatory requirements and improving the accuracy of radar-based water-level monitoring systems.
基于雷达的水位监测需要具有窄波束、高增益和低旁瓣的天线。现有的喇叭天线和串联馈电微带阵列要么缺乏紧凑性，要么存在与频率相关的波束偏差，这会降低传感精度。本文提出了一种用于水位雷达的工作在K波段的256元缝隙耦合平面微带阵列。该阵列将大规模集成与缝隙耦合馈电相结合，可提供固有的180°相位校正，并能在整个频率范围内稳定主波束。所制作的阵列整体尺寸为140毫米×160毫米×1.12毫米。仿真结果显示，峰值增益为22.8 dBi，波束宽度在E平面为5.2°，在H平面为4.2°，并且在25.9 - 27.0 GHz范围内波束偏差保持在0.5°以内。相比之下，具有相同孔径的串联馈电阵列的偏差高达7.5°，且其宽边增益仅为15.8 dBi。这些结果表明，所提出的缝隙耦合阵列提供了一种紧凑的天线解决方案，满足了监管要求并提高了基于雷达的水位监测系统的精度。
