In this paper, a millimeter‐wave Butler matrix with flexible phase differences is proposed using the substrate integrated suspended line technology. To begin with, a low‐loss substrate integrated suspended line (SISL) circular patch coupler consisting of four circular sectors is presented, achieving arbitrary phase difference and coupling coefficient by adjusting the angle and radii of the sectors. Based on the proposed coupler, two prototypes of the SISL Butler matrix are designed, fabricated and measured for the demonstration. In prototype I, the crossovers are removed and a flexible phase difference is obtained with an area size of 2.5 λ_g × 2.8 λ_g. In prototype II, both the crossovers and 45° phase shifters are removed and the phase differences of ±45° and ±135° are obtained with an area size of 1.86 λ_g × 2.24 λ_g. Low crosstalk between components and minimal radiation loss can be achieved by the SISL self‐packaged characteristic and electromagnetic shielding. For both prototypes, the measured insertion losses are less than 2 dB at 26 GHz, including the loss of transitions and connectors, and the measured phase errors are less than ±10° within a bandwidth of more than 10%. The proposed Butler matrix shows the advantages of compact size, low loss and high integration.

中文翻译：

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基于具有任意相位差和耦合系数的低损耗衬底集成悬浮线贴片混合耦合器的柔性毫米波巴特勒矩阵

在本文中，利用衬底集成悬浮线技术提出了一种具有灵活相位差的毫米波巴特勒矩阵。首先，提出了一种由四个圆形扇区组成的低损耗基板集成悬浮线（SISL）圆形贴片耦合器，可通过调整扇区的角度和半径来实现任意的相位差和耦合系数。基于提出的耦合器，设计，制造和测量了两个SISL巴特勒矩阵原型，以进行演示。在原型I中，分频器被移除并且由具有2.5的面积大小而获得的柔性相位差λ_克 ×2.8 λ_克。在原型II，无论是分频器和45°移相器除去，并用1.86的区域尺寸得到°±45°和±135的相位差λ_克 ×2.24 λ_克。通过SISL自包装特性和电磁屏蔽，可以实现组件之间的串扰低且辐射损失最小。对于两个原型，在26 GHz时测得的插入损耗均小于2 dB，包括过渡和连接器的损耗，并且在超过10％的带宽内，测得的相位误差均小于±10°。提出的巴特勒矩阵显示出紧凑的尺寸，低损耗和高集成度的优点。