This paper proposes a low loss 4 × 4 Butler matrix based on rectangular waveguide cavity resonators technology for millimeterwave beamforming network using iris coupling method. This method has the advantage of controlling the electrical fields and the coupling factor inside a complex medium such as waveguide cavity resonators. The coupling factor of 6 dB for 4 × 4 Butler matrix is achieved by tuning the iris coupling k-value between the waveguide cavity resonators. Thus, avoiding a higher phase difference losses and component losses at upper millimeterwave bands. To validate the proposed method, CST software simulations are performed under several iris coupling k-values to achieve a 6 dB coupling factor. Then, the proposed 4 × 4 Butler matrix is 3D metal printed using selective laser melting (SLM) technique. The measured reflection and isolation coefficients are observed below −10 dB, with coupling coefficients ranging between −6 and −7 dB. The phase differences of −42.02°, 42.02°, −130.95°, and 133.3° are achieved at the outputs. It confirmed that using this proposed method has the superiority over the conventional microstrip and waveguide coupling methods by a 1 dB coupling factor loss and a 3° phase difference error.

本文针对使用虹膜耦合方法的毫米波波束形成网络提出了一种基于矩形波导腔谐振器技术的低损耗 4×4 Butler 矩阵。这种方法的优点是可以控制波导腔谐振器等复杂介质内部的电场和耦合因子。4 × 4 Butler 矩阵的 6 dB 耦合因子是通过调整波导腔谐振器之间的虹膜耦合k值来实现的。因此，避免了较高毫米波段的较高相位差损耗和元件损耗。为了验证所提出的方法，CST 软件模拟在几个虹膜耦合k-值以实现 6 dB 的耦合系数。然后，使用选择性激光熔化 (SLM) 技术对所提出的 4 × 4 Butler 矩阵进行 3D 金属打印。测得的反射和隔离系数低于 −10 dB，耦合系数介于 −6 和 −7 dB 之间。在输出端实现了 −42.02°、42.02°、−130.95° 和 133.3° 的相位差。它证实了使用这种提出的方​​法比传统的微带和波导耦合方法具有 1 dB 耦合因子损耗和 3° 相位差误差的优势。