Photonic THz Generation and Quasioptical Integration for Imaging Applications
Doktorsavhandling, 2009

This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequency range. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. Furthermore, a novel and compact catadioptric lens is proposed and investigated for realising compact sensing systems. Radiating elements and components can be physically coupled to the lens in order to achieve short-range focusing and sensing ability. Using physical device modelling, the limitations and optimisation of InGaAs/InP based UTC-PDs for attaining higher bandwidth as well as higher output power are discussed. A hydrodynamic (HD) carrier transport model is used to analyse the device. Optimising for output power requires trade-offs involving the epitaxial layer design, optical coupling, circuit design and antenna design. An example of UTC-PD epitaxial layer optimisation for continuous-wave THz generation at 340 GHz is shown using the HD model. The output power and the optimum embedding impedance for the UTC-PD, as a function of device parameters, are also studied at different optical injection levels. Several plausible integration schemes and antenna design examples at 340 GHz are explored. A novel catadioptric lens, suitable for microwave and terahertz applications, is presented. The focusing property of the lens is investigated using 3D full-wave electromagnetic solvers. The proposed catadioptric lens is designed and fabricated from Delrin and Macor. Simulation and characterisation results are presented at microwave and terahertz frequencies (108 GHz). The results show that although being a few wavelengths (λ) in dimension, the catadioptric lens provides short-range focusing in the close vicinity (~λ) and therefore provides a compact solution for short-range imaging systems. Finally, several short-range imaging examples at 108 GHz, employing the catadioptric lenses, are also presented and discussed.

nondestructive evaluation

semiconductor device modelling

uni-travelling-carrier photodiodes

millimetre wave and submillimetre wave generation

III-V semiconductors


terahertz sources.

catadioptric lens

microwave imaging

dielectric loaded antennas

terahertz imaging

lens antennas

millimetre wave and submillimetre wave imaging

Kollektorn (A423), MC2, Kemivägen 9, Chalmers, Göteborg.
Opponent: Prof. Dr. Hartmut Roskos, Johann Wolfgang Goethe-Universität, Frankfurt, Germany.


Biddut Kumar Banik

Chalmers, Teknisk fysik, Fysikalisk elektronik

A novel catadioptric dielectric lens for microwave and terahertz applications

Microwave and Optical Technology Letters,; Vol. 50(2008)p. 416-419

Artikel i vetenskaplig tidskrift

Catadioptric Dielectric Lens for Imaging Applications

Proceedings of 33rd International Conference on Infrared, Millimeter, and Terahertz Waves,; (2008)p. 1 - 2

Paper i proceeding

Optimization of the UTC-PD Epitaxy for Photomixing at 340 GHz

International Journal of Infrared and Millimeter Waves,; Vol. 29(2008)p. 914-923

Artikel i vetenskaplig tidskrift

Microwave S-parameter Characterization of an Antenna-Coupled Catadioptric Lens

IEEE Antennas and Wireless Propagation Letters,; Vol. 8(2009)p. 1299-1301

Artikel i vetenskaplig tidskrift

Millimeter Wave Characterization of a Catadioptric Lens for Imaging Applications

IEEE Microwave and Wireless Components Letters,; Vol. 19(2009)p. 680-682

Artikel i vetenskaplig tidskrift



Elektroteknik och elektronik

Annan elektroteknik och elektronik



Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: MC2-151

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3000

Kollektorn (A423), MC2, Kemivägen 9, Chalmers, Göteborg.

Opponent: Prof. Dr. Hartmut Roskos, Johann Wolfgang Goethe-Universität, Frankfurt, Germany.

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