Unknown dielectric properties of RF/microwave substrates cause headaches for microwave circuit and antenna designers. Most commercial reinforced dielectric substrates made from layers of woven‐glass and/or ceramic fillings lead to dielectric anisotropy. Often, re‐optimization and even re‐fabrication of designed prototypes are required when measuring results are found to be departed from the prediction. These are time consuming and costly. In order to determine the unknown complex permittivity of any substrates, this paper describes a hybrid approach composed of two measurement stages. The first stage is the coaxial‐probe method for predicting an initial complex permittivity of unknown dielectric substrates, which is known as the perpendicular permittivity. The second stage is the microstrip open‐circuit stub (OCS) method that regulates the complex permittivity of the dielectric laminate by mapping the input impedance curves of OCS via electromagnetic simulation and actual measurement. Three dielectric substrates without prior dielectric properties were selected to validate the proposed method. The equivalent dielectric constants, dissipation factors and dielectric anisotropies were determined and compared. The proposed method is found to be reliable for determining the unknown properties of dielectric substrates.

中文翻译：

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使用混合方法确定未知基材的介电性能

RF /微波基板的未知介电性能使微波电路和天线设计人员头痛。大多数由机织玻璃和/或陶瓷填充物制成的增强电介质基材会导致介电各向异性。当发现测量结果与预测结果有出入时，通常需要对设计的原型进行重新优化甚至重新制造。这些既费时又昂贵。为了确定任何基质的未知复介电常数，本文介绍了一种由两个测量阶段组成的混合方法。第一步是同轴探针法，用于预测未知电介质基板的初始复介电常数，这称为垂直介电常数。第二阶段是微带开路短线（OCS）方法，该方法通过电磁仿真和实际测量绘制OCS的输入阻抗曲线来调节介电层压板的复介电常数。选择了三种没有先验介电性能的介电基板，以验证所提出的方法。确定并比较了等效介电常数，耗散因数和介电各向异性。发现所提出的方法对于确定介电基板的未知特性是可靠的。确定并比较了耗散因子和介电各向异性。发现所提出的方法对于确定介电基板的未知特性是可靠的。确定并比较了耗散因子和介电各向异性。发现所提出的方法对于确定介电基板的未知特性是可靠的。