A Novel Approach for Improving Off-Axis Pixel Performance of Terahertz Focal Plane Arrays
A Novel Approach for Improving Off-Axis Pixel Performance of Terahertz Focal Plane Arrays
复制标题
提高太赫兹焦平面阵列离轴像素性能的新方法
DOI：
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发表时间：
2010
影响因子：
4.3
通讯作者：
P. Smith
中科院分区：
文献类型：
--
作者：
G. Trichopoulos;G. Mumcu;K. Sertel;H. L. Mosbacker;P. Smith
提出了一种天线工程方法，以显着提高太赫兹焦平面阵列（FPA）的离轴检测性能的扩展半球透镜后面。特别是，在一个大的焦平面离轴像素的天线进行了重新设计，表现出倾斜的接收模式。新的天线结构校正了由于小透镜尺寸而导致的离轴传感器中的波束失真。具体地说，这种方法非常适合与高灵敏度异质结构后向二极管集成的单片天线结构。虽然该方法被证明为100-和500-GHz的FPA，所提出的技术同样适用于其他平面天线拓扑结构和传感器材料，以及进入太赫兹制度。此外，标准的RF阻抗匹配技术被用来提高响应性能的二极管耦合FPA。对于固定的透镜尺寸，光束校正技术允许5倍更大尺寸的FPA。我们还注意到，高斯性和方向性之间的权衡对于较大的透镜变得必要。因此，增加FPA的尺寸，而不借助于增加透镜尺寸，能够实现改善的耦合效率（高斯性）以及更好的像素分辨率（方向性）。
We present an antenna engineering approach to significantly improve off-axis detection properties of terahertz focal plane arrays (FPAs) behind an extended-hemispherical lens. In particular, antennas in the off-axis pixels in a large FPA were redesigned to exhibit tilted receiving patterns. The new antenna structure corrects for beam distortions in off-axis sensors due to the small lens size. Specifically, this approach is well suited for monolithic antenna structures integrated with high-sensitivity heterostructure backward diodes. Although the approach is demonstrated for 100- and 500-GHz FPAs, the presented technique is equally applicable to other planar antenna topologies and sensor materials that operate well into the terahertz regime. In addition, standard RF impedance-matching techniques were used to improve responsivity performance of the diode-coupled FPAs. The beam-correction techniques allow for a factor-of-5 larger size FPA for a fixed lens size. We also note that a tradeoff between Gaussicity and directivity becomes necessary for larger lenses. Thus, increasing the size of the FPA, without resorting to increasing the lens size, enables improved coupling efficiencies (Gaussicity) as well as better pixel resolution (directivity).