The paper describes the development of passive, chipless tags for a novel indoor self-localization system operating at high mm-wave frequencies. One tag concept is based on the low-Q fundamental mode of dielectric resonators (DR) which exhibits peak scattering at its resonance frequency. As the radar cross-section (RCS) of DRs at mm-wave frequencies is far too low for the intended application, arrays of DRs and combinations with dielectric lens and corner reflectors are investigated to boost the RCS while keeping the scattering retro-directive over wide-angle incidence. Satisfactory results are demonstrated experimentally in W-band with metal corner reflectors combined with planar arrays of DRs; the tags produce a high RCS level over a moderately broad angular range and a wide frequency range where they exhibit a notch at the resonance frequency of the dielectric resonators. These designs suffer from low coding range of 3 to 6 bit, degradations of RCS in angular range, and a difficult separation of the tag response from strong clutter. Both the suppression of large clutter interference by using time gating of the tag response and a larger coding range are promised by a chipless tag concept based on multiple high-Q resonators in photonic crystal (PhC) technology. Experimental samples are characterized as transmission resonators and as retro-directive tags at the 230 GHz band. As a concept to boost the retro-directive RCS with a truly wide-angle response, the integration of PhC resonators with a Luneburg lens is discussed.

中文翻译：

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频率编码毫米波标签，用于使用介电共振器的自定位系统

该论文描述了一种用于在高毫米波频率下运行的新型室内自定位系统的无源无芯片标签的开发。一种标签概念是基于介电共振器（DR）的低Q基本模式，该模式在其共振频率处表现出峰值散射。由于毫米波频率下DR的雷达横截面（RCS）对于预定的应用而言太低了，因此研究了DR阵列以及与介电透镜和角反射器的组合以增强RCS，同时保持散射向后方向广角入射。用金属角反射器结合DR的平面阵列在W波段进行实验，结果令人满意。标签在适中的宽角度范围和宽频率范围内产生高的RCS电平，其中它们在介电谐振器的谐振频率处显示出一个缺口。这些设计遭受3到6位的低编码范围，角度范围内的RCS下降以及标签响应与强杂波难以分离的问题。通过使用光子晶体（PhC）技术中的多个高Q谐振器的无芯片标签概念，有望通过使用标签响应的时间门控来抑制大的杂波干扰和更大的编码范围。实验样本的特征是在230 GHz频段上具有传输谐振器和定向标记。作为用真正的广角响应增强逆向RCS的概念，讨论了PhC谐振器与Luneburg透镜的集成。