Two-dimensional subwavelength-focused imaging using a near-field probe at a λ/4 working distance
Two-dimensional subwavelength-focused imaging using a near-field probe at a λ/4 working distance
复制标题
使用近场探头在 λ/4 工作距离进行二维亚波长聚焦成像
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
G. Eleftheriades
中科院分区：
文献类型：
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作者：
L. Markley;G. Eleftheriades
实验研究了近场天线阵列探头在λ/4距离下的二维亚波长成像。由小物体的存在引起的场扰动通过监测探头扫描时的输入反射系数来检测。该探头设计用于产生具有0.217λ半峰全宽光束宽度的亚波长焦斑。通过相消干涉来抑制衰减分量，增强渐逝场，足以分辨间隔为0.259λ的物体。在这个工作距离的传统的单元件探头的解决能力差，它示出，即使是间隔在一个波长分开的物体被不准确地检测。一个完整的2D成像实验进行了使用八个分散的对象。单元件探头无法分辨任何物体，而除了两个最接近的对之外，所有的对都被阵列探头分辨。
Two-dimensional (2D) subwavelength imaging using a near-field antenna array probe is demonstrated experimentally at a probe-to-object separation distance of λ/4. Field perturbations caused by the presence of small objects are detected by monitoring the input reflection coefficient as the probe is scanned. The probe is designed to produce a subwavelength focal spot with a 0.217λ full-width half-maximum beam width. Propagating components are suppressed through destructive interference, enhancing the evanescent field enough to resolve objects spaced by 0.259λ. The poor resolving capability of a conventional single-element probe at this working distance is also addressed; it is shown that even objects spaced over a wavelength apart are inaccurately detected. A full 2D imaging experiment is carried out using eight scattered objects. The single element probe is unable to resolve any of the objects, while all but the two most closely spaced pairs are resolved by the array probe.