In this study, we report a low-symmetric photonic crystal (PhC) structure that exhibits high coupling efficiency in a broadband frequency range with a tilted self-collimating capability. First, the analytical approach is implemented as a starting point, and the ideal configuration is chosen for the self-collimation effect, which is analytically supported by group velocity dispersion and third-order-dispersion calculations. Then, numerical analyses in both time and frequency domains are performed to the ideal PhC design, which possesses a strong self-collimating characteristic, even at huge incident angles within the operating frequencies. Later, experimental measurements are conducted in microwaves, and the existing self-collimation property is still preserved at longer wavelengths in the millimeter scale. The microwave experiment as well as numerical analyses indicate that the designed PhC self-collimator allows overcoming possible misalignment problems at the PhC–source interface and enables a strong broadband beam channeling with a high transmission.

中文翻译：

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C2对称光子晶体中的宽带自准直

在这项研究中，我们报告了一种低对称光子晶体（PhC）结构，该结构在具有倾斜自准直能力的宽带频率范围内表现出高耦合效率。首先，将分析方法作为起点，并为自准直效果选择理想的配置，并通过群速度色散和三阶色散计算为分析提供支持。然后，对时域和频域进行数值分析，以实现理想的PhC设计，该设计即使在工作频率内的入射角很大时也具有很强的自准直特性。后来，在微波中进行了实验测量，并且现有的自准直特性仍保留在毫米级的更长波长下。