A novel approach for improving off-axis pixel performance of terahertz focal plane arrays

Georgios C. Trichopoulos, Gokhan Mumcu, Kubilay Sertel, H. Lee Mosbacker, Phil Smith

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

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).

Original languageEnglish (US)
Article number5491268
Pages (from-to)2014-2021
Number of pages8
JournalIEEE Transactions on Microwave Theory and Techniques
Volume58
Issue number7 PART 2
DOIs
StatePublished - Jul 1 2010
Externally publishedYes

Keywords

  • Focal plane arrays (FPAs)
  • Medical imaging
  • Millimeter waves
  • Quasi-optical
  • Security screening
  • Terahertz sensors

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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