This letter presents a compact 2-D Butler matrix (BM) realized by multilayer substrate integrated waveguide (SIW) technology. The 2-D BMs in the open literature suffer from either bulky size or poor integration with the radiation portion. Facing this issue, a new SIW 2-D BM is developed and realized in planar configuration easily integrated with the slot antenna array. The key point of this letter is to design planar 2-D components, including 2-D couplers, 2-D crossovers, and 2-D phase shifters, of the proposed SIW 2-D BM, which can perform coupling, intersection, or phase shifting in both E- and H-planes. The proposed SIW 2-D BM also has the merit of ease integration with radiation portion and it is used to build a compact 2-D multibeam antenna in this letter. Simulation, fabrication, and experiments are conducted to verify the performance of the realized 2-D multibeam antenna.

中文翻译：

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紧凑型SIW二维Butler矩阵及其多波束应用

这封信介绍了通过多层基板集成波导（SIW）技术实现的紧凑型二维Butler矩阵（BM）。开放文献中的2-D BM体积大或与辐射部分的整合性差。面对这个问题，开发了一种新的SIW 2-D BM，并以平面配置实现，可以轻松地与缝隙天线阵列集成。这封信的重点是设计提出的SIW 2-D BM的平面2-D组件，包括2-D耦合器，2-D分频器和2-D相移器，它们可以执行耦合，相交或E平面和H平面的相移。所提出的SIW 2-D BM还具有易于与辐射部分集成的优点，并且可用于构建紧凑的2-D多波束天线。模拟，制作，