Characteristic Impedance Adjustment of Thin-Metal Mesh Transmission Lines for mmWave Display-Integrated Antennas

This paper proposes four methods and empirical formulas of adjusting characteristic impedances for thin-metal mesh transmission lines. The characteristic impedances are discretely adjusted by changing the number and the size of unit meshes, which provides macro-tuning capability, and the discrete values can be tuned more precisely by varying the thin-metal line width and the aspect ratio of mesh geometry. The validity of proposed methods is confirmed by full-wave numerical simulations, and the simulated impedance variations are well-described by our empirical formulas. For further verifications, 26 distinguished samples of thin-metal mesh transmission lines and a 28-GHz thin-metal mesh antenna are fabricated, and their characteristics are measured in millimeter-wave spectrums. The measured results confirm that the proposed methods and empirical formulas can provide accurate and more flexible design rules for impedance adjustment, which allows potential advances in display-integrated antenna applications.