| 1. |
- Banik, Biddut Kumar, 1978, et al.
(author)
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High Power Photonic MW/THz Generation Using UTC-PD
- 2008
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In: GigaHertz SympoSium 2008. ; , s. 45-
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Conference paper (peer-reviewed)abstract
- The ongoing research work concentrates on extending the previously accomplished UTC-PD fabrication and modelling techniques to 340 GHz and above. We have fabricated and characterized UTC-PDs intended for high power MW/THz generation. Several integrated antenna-detector circuits have been designed and characterised.
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| 2. |
- Banik, Biddut Kumar, 1978, et al.
(author)
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UTC-PD Integration for Submillimetre-wave Generation
- 2008
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In: 19th International Symposium on Space Terahertz Technology, ISSTT 2008; Groningen; Netherlands; 28 April 2008 through 30 April 2008. ; , s. P7-1, 135
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Conference paper (peer-reviewed)abstract
- Because of the inherent difficulty to generate power in the frequency range 0.l-10 THz, the term 'THzgap' has been coined. Among a number of MW/THz generation techniques, the photomixer based sources hold high potential offering wide tunability and decent amounts of output power. The photomixing technique relies on the nonlinear mixing of two closely spaced laser wavelengths generating a beat oscillation at the difference frequency. In recent years, there has been an increasing interest in the Uni-Travelling-Carrier PhotoDiode (UTCPD) [1] for photomixing, photo receivers, MW/THz-wave generation, fibre-optic communication systems, and wireless communications. UTC-PDs have become very promising by demonstrating output powers of 20 mW at 100 GHz [1] and 25 μW at 0.9 THz [2].
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| 3. |
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| 4. |
- Rafique, Raihan, 1978, et al.
(author)
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Miniaturization of superconducting passive filters for on-chip applications
- 2007
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In: 11th International Superconducting Electronics Conference, Washington DC, USA, June 10-14, 2007.. ; 11, s. P-V09
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Conference paper (other academic/artistic)abstract
- We present techniques to miniaturize superconducting ultra narrowband filters for on-chip applications. The filters are designed for 2 GHz, 5 GHz and 10 GHz operating frequencies. The expected bandwidths of the designed filters are 2-20 MHz. The designs are of 7 stages Chebyshev filters having maximum passband ripples of 0.5 dB. On-chip filters are particularly interesting as they are applicable for monolithic design with the RSFQ circuit aiming qubit applications. One of the designs is a quasi-lumped filter where the effective wave propagation constant has been increased by the addition of lumped components to the superconducting microstrip line (SMSL). Additionally, this design provides the optimum width of an SMSL without violating design rules. The other design consists of distributed and lumped components. The area of the filter is in the range of 1-2 square mm. We present the filter topologies and corresponding experimental results for the frequency response of these on-chip filters designed for Hypres 4.5 kA/cm2 fabrication process.
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| 5. |
- Rafique, Raihan, 1978, et al.
(author)
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Miniaturized superconducting microwave filters
- 2008
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In: Superconducting Science and technology, press.
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Journal article (peer-reviewed)abstract
- In this paper we present methods for miniaturization of superconducting filters. We consider two designs of 7th order bandpass Chebyshev filters based on lumped elements and a novel quasi-lumped element resonators. In both designs the area of the filters, with a central frequency of 2-5 GHz, is less than 1.2 mm2. Such small filters can be readily integrated on one board for multi-channel microwave control of superconducting qubits. The filters have been experimentally tested and the results are compared with simulations. The miniaturization resulted in parasitic coupling between resonators and within eachresonator that affected primarily stopband and bandwidth increase. The severity of the error depends on the design in particular, and was less prawn when groundplane was used under the inductances of the resonators. The best performance was reached for the quasi-lumped filter with central frequency of 4.5 GHz, quality factor of 100 and 28 dB stopband.
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| 6. |
- Stake, Jan, 1971, et al.
(author)
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Terahertz technology and applications
- 2008
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In: International Symposium on Terahertz between Japan and Sweden.
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Conference paper (other academic/artistic)abstract
- THz or submillimetre-wave sensing covers the frequency range from 300 GHz to 10 THz (wavelengths from 1 mm to 30 µm). With energy levels in the 1.2-40 meV range, terahertz interactions with matter involve intermolecular, rather than atomic transitions. This gives rise to some imaging and spectroscopy applications that are unique to this particular region of the electromagnetic spectrum. Many polar molecules in the low pressure gaseous state have strong, narrow band, vibrational and rotational emission or absorption modes that peak in this regime and are used as probes for quantum chemistry, astrophysical processes and the dynamics of planetary atmospheres, including the Earth. Still, the terahertz spectral region is by far the least explored portion of the electromagnetic spectrum. A great obstacle has been the absence of robust and reasonable inexpensive receiver components that can operate at room temperature. The talk will consist of two parts: a) room temperature technology for THz applications and b) terahertz applications in biology and medicine.At Chalmers, several key technologies are explored for future THz systems such as radiometers, radars, spectrometers and communication links for frequencies from approximately 100GHz to several THz. Transistors with 50 nm gate length based on the two dimensional electron gas can at present be used for frequencies up to and above 300 GHz for circuits such as amplifiers, frequency mixers, frequency multipliers, oscillators, and modulators. For even higher frequencies, submicron low noise Schottky diodes are used for heterodyne mixers. We are currently pursuing studies of high functionality THz mixers (SSB) and in-house fabrication of monolithically integrated Schottky diode circuits. Results and progress on single side band mixers at 340 GHz aimed for future climate research satellites such as the ESA PREMIER mission. Furthermore, single chip receivers (MMIC) up to 220 GHz for imaging applications will be presented.THz imaging and spectroscopy for biomedical applications is being targeted for the very first time, including assessment of protein conformational states, molecular binding and interaction, DNA hybridization, isomer identification, skin hydration level, drug delivery, wound healing, tumour identification and margin assessment, and cell processes. The submillimeter wave advanced technology group at Caltech, in conjunction with the group at Chalmers (J.Stake was visiting Caltech under a sabbatical), set up a very flexible exposure and monitoring system to be used to systematically investigate the interaction of THz radiation with cells.The talk will cover the latest results obtained from Chalmers on MMICs and Schottky diode mixers for terahertz frequencies (sensors), as well as results from initial investigations towards thermal and non-thermal effects of THz radiation on biological systems (Caltech/JPL-Chalmers).
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| 7. |
- Banik, Biddut Kumar, 1978, et al.
(author)
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A novel catadioptric dielectric lens for microwave and terahertz applications
- 2008
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In: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 50:2, s. 416-419
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Journal article (peer-reviewed)abstract
- A novel dielectric catadioptric lens, suitable for near-field sensing and imaging, is presented. The focusing property and the far-field pattern of the lens are investigated using a 3D full-wave electromagnetic solver. Furthermore, the proposed catadioptric lens has been designed and fabricated from Delrin. Simulations and measurements of the far-field at 5 GHz and return loss versus frequency using a Bow-tie slot feeding antenna are presented.
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| 8. |
- Banik, Biddut Kumar, 1978, et al.
(author)
-
Catadioptric Dielectric Lens for Imaging Applications
- 2008
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In: Proceedings of 33rd International Conference on Infrared, Millimeter, and Terahertz Waves. - 9781424421190 ; , s. 1 - 2
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Conference paper (peer-reviewed)abstract
- The design and characterization results of a novel catadioptric dielectric lens are presented. Although being electrically small, the lens provides a focus in the close vicinity which makes it suitable to be used in microwave and terahertz systems. Several lenses of different dielectric materials and dimensions have been fabricated. A simple backscattering measurement method has been implemented in order to determine the focusing property of the lens.
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| 9. |
- Banik, Biddut Kumar, 1978, et al.
(author)
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Catadioptric Microlenses for Submillimeter and Terahertz Applications
- 2006
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In: 17th International Symposium on Space THz Technology – ISSTT 2006.
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Conference paper (peer-reviewed)abstract
- Existing dielectric lens geometries are optimized for remote sensing applications in order to produce a predetermined Gaussian beam in the far field that is matched to a radioastronomic setup. In this work, an optics suitable forobject investigation in a point-to-point transmission setup is presented. Here it is required to create a focus point outside the lens with as low radiation leakage as possible. For this, a catadioptric dielectric lens is proposed. This paper presents the theoretical performance of the focusing property of catadioptric lens investigated at 50 GHz and 228 GHz having er = 11.7. 3D simulation results of the catadioptric lens also show a focus point. Imaging property of catadioptric and extended hemispherical lenses are presented and compared at 50GHz. A Transient analysis of the lens is also presented.
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| 10. |
- Banik, Biddut Kumar, 1978, et al.
(author)
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Design of Antenna Integrated Photomixers and Catadioptric Lenses for Emerging THz Applications
- 2008
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In: 2008 ANSYS Regional Conference.
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Conference paper (other academic/artistic)abstract
- We will present design and modeling of antenna integrated photomixers for terahertz generation. In addition, the design and the quasioptical integration a novel catadioptric dielectric lens, suitable for imaging applications, will be presented. Although having a tremendous potential, the terahertz (0.1 – 10 THz) regime in the frequency spectrum and its applications are hindered due to the lack of viable and high power terahertz sources. This has led to the term “terahertz gap” being coined. We aim to construct compact sources utilizing the lens-coupled antenna-integrated photomixer sources based on Uni-Travelling-Carrier Photomixers (UTC-PD). These sources are one of the key components which could significantly bridge the terahertz gap.However, optimization of the epitaxial layer structure of the UTC-PD is necessary for high-power THz generation. The epilayers of the UTC-PD is designed and optimized in TCAD. Antennas are designed using HFSS while the impedance of the antenna at a specific bandwidth from HFSS is used to optimize the UTC-PD epilayers and vice versa. Thus proper impedance match and therefore high power THz generation is possible.A novel catadioptric dielectric lens is designed and characterized using HFSS. The lens provides an alternative solution to be used as a focusing element and therefore suitable for imaging or similar applications.In fine, we aim to combine the photomixer source and the lens in order to attain compact but powerful THz sources.
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| 11. |
- Banik, Biddut Kumar, 1978, et al.
(author)
-
Development and Design of a 340 GHz Photomixer Source
- 2007
-
In: 18th International Symposium on Space THz Technology – ISSTT 2007.
-
Conference paper (peer-reviewed)abstract
- We present the design of an InGaAlAs/InP uni-traveling-carrier photo-diode (UTC-PD) at mm-wave frequencies up to 340 GHz. The photo diode epitaxy is optimized using a quasi-3D software implementing the hydrodynamic semiconductor equations, for which an output power of 3 mW at 340 GHz was simulated. An equivalent circuit of the UTC-PD has been fitted to experimental S11 measurements up to 67 GHz. Finally, an optimized antenna coupled UTC-PD with choke filter has been designed. This MMIC circuit is intended for photomixing, with output power at 340 GHz.
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| 12. |
- Banik, Biddut Kumar, 1978, et al.
(author)
-
Microwave S-parameter Characterization of an Antenna-Coupled Catadioptric Lens
- 2009
-
In: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 8, s. 1299-1301
-
Journal article (peer-reviewed)abstract
- The focusing property of a bow-tie antenna coupled catadioptric lens is studied experimentally using a vector measurement setup. The results show that the lens-antenna provides short-range focusing. Furthermore, the return loss of the lens-antenna was determined numerically and confirmed experimentally from 1 GHz to 10 GHz. The lens-antenna provides 60% bandwidth (VSWR ≤ 2) centered at 6 GHz. Finally, the lens-antenna was employed to detect and locate buried objects and results are presented.
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| 13. |
- Banik, Biddut Kumar, 1978, et al.
(author)
-
Millimeter Wave Characterization of a Catadioptric Lens for Imaging Applications
- 2009
-
In: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 19:11, s. 680-682
-
Journal article (peer-reviewed)abstract
- Characterization of a catadioptric dielectric lens-horn configuration for short-range sensing and imaging is presented. The focusing property is investigated both numerically and experimentally at 108 GHz. The lens-horn provides a focal spot of ~ 0.9λ at a distance of ~ 4.5λ. An imaging example employing the lens in a CW imaging setup is presented. A test pattern was imaged and a marked improvement in image resolution was observed. With the aid of the lens, features close to the wavelength are resolved, which are absent or indistinguishable otherwise.
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| 14. |
- Banik, Biddut Kumar, 1978, et al.
(author)
-
Optimization of the UTC-PD Epitaxy for Photomixing at 340 GHz
- 2008
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In: International Journal of Infrared and Millimeter Waves. - : Springer Science and Business Media LLC. - 0195-9271 .- 1572-9559. ; 29:10, s. 914-923
-
Journal article (peer-reviewed)abstract
- We present a method to optimize the epitaxial layer structure of an InGaAs/InP uni-traveling-carrier photo-diode (UTC-PD) for continuous THz-wave generation. The design approach used is general in that it can be applied for any target frequency while this study focuses on 340 GHz. The photodiode epitaxy is modeled and optimized using a TCAD software implementing the hydrodynamic semiconductor equations. This physical device model was found to be in good agreement with reported experimental results. It is shown that the UTC-PD can generate ~1 mW at 340 GHz by choosing the optimum absorption layer and collection layer thicknesses.
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| 15. |
- Banik, Biddut Kumar, 1978
(author)
-
Photonic terahertz-wave generation, radiation and quasioptical integration
- 2007
-
Licentiate thesis (other academic/artistic)abstract
- This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. An equivalent circuit of the UTC-PD is also proposed and has been fitted to S11 measurements up to 67 GHz.Several plausible quasioptical and non-quasioptical integration schemes for different UTC-PD application areas have also been discussed. Optimising for output powerrequires careful tradeoffs involving the epitaxial layer design, optical coupling, circuit design and antenna design. Considering the tradeoffs, several schemes for free-spaceTHz generation and waveguide integration techniques have been discussed.A novel catadioptric lens which is suitable for microwave and terahertz applications, for instance near-field imaging, has been presented. The focusing property of the lens hasbeen investigated using a 3D full-wave electromagnetic solver. Furthermore, the proposed catadioptric lens has been designed and fabricated from Delrin. Simulation andmeasurement results have been presented.
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| 16. |
- Banik, Biddut Kumar, 1978
(author)
-
Photonic THz Generation and Quasioptical Integration for Imaging Applications
- 2009
-
Doctoral thesis (other academic/artistic)abstract
- This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequencyrange. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. Furthermore, a noveland compact catadioptric lens is proposed and investigated for realising compact sensing systems. Radiating elements and components can be physically coupled to the lens inorder 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 optimisationfor 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 ofdevice 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 theclose vicinity (~λ) and therefore provides a compact solution for short-range imaging systems. Finally, several short-range imaging examples at 108 GHz, employing thecatadioptric lenses, are also presented and discussed.
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| 17. |
- Banik, Biddut Kumar, 1978, et al.
(author)
-
VO2 TES as Room Temperature THz Detectors
- 2006
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In: 17th International Symposium on Space THz Technology – ISSTT 2006.
-
Conference paper (peer-reviewed)abstract
- Abstract VOx materials hold very high potential to be used as room temperature bolometer. A brief review on room temperature bolometers and VOx characteristics is presented. The hysteretic metal-insulator transition behavior of a VOxmicrobolometer has been investigated. An algebraic hysteresis model has been used to model the resistance-temperature characteristic of the bolometer. The magnetic limiting loop proximity (L2 P) hysteresis theory is modified to represent the VOx major and minor hysteresis loops. The responsivity of the bolometer is also calculated. Loop accommodation process is explained. Nonsymmetrical hysteretic behavior has also been discussed.
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| 18. |
-
International Symposium on Terahertz Science and Technology between Japan and Sweden
- 2009
-
Editorial collection (peer-reviewed)abstract
- The organisers and hosts warmly welcome you to the second International Symposium on Terahertz Science and Technology between Japan and Sweden, at Chalmers University of Technology, Göteborg, on November 18-20, 2009. The symposium is organised by the Department of Microtechnology and Nanoscience (MC2) at Chalmers. The aim is to create a forum and platform where researchers from the two countries can discuss latest results and trends in the field of terahertz science and technology. This year we have two keynote and 19 invited lectures divided into nine sessions.Sandwiched between the optical on the short wavelength side and radio on the long wavelength extreme, the terahertz (THz) or far-infrared has long been considered the last remaining scientific gap in the electromagnetic spectrum. The broad spectrum of THz applications has attracted researchers from different disciplines dealing with optics and photonics, microwave engineering and semiconductor physics. The role of this meeting is not only bridging the THz-gap but also strengthening the collaboration between Japan and Sweden.Chalmers is a university of technology in which research and teaching are conducted on a broad front within technology, natural science and architecture. Chalmers was founded in 1829. The university is named after the major benefactor, William Chalmers, one of the directors of the successful Swedish East India Company in Göteborg. Chalmers became an independent foundation in 1994. The meeting will be held at William Chalmers private residence, Chalmerska huset, which was erected in 1805-1807 and designed in a neoclassical style.The workshop is sponsored by the Swedish Research Council (VR) and MC2, Chalmers. We would like to thank these organisations for their support. We would also like to thank everyone who helped to arrange Japan-Sweden Terahertz Symposium (JSTS) 2009: the international steering committee for advice; the local organising committee: Eva Hellberg, Aleksandra Malko, Aik-Yean Tang, Dr. Sergey Cherednichenko, Dr. Biddut Banik and Prof. Dag Winkler for all practical efforts; Eriko Naito and Prof. Anders Karlsson at the Embassy of Sweden in Tokyo; our host Anna Bergius Hartman during the stay in Chalmerska huset; Dr. Göran Alestig for arranging the lab tour; invited speakers and everyone who attends or contributes to this event.On behalf of the local organising committee, we would like to welcome you all and wish you a pleasant and fruitful stay in Göteborg.Welcome!Jan Stake JSTS 2009 Chairman
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| 19. |
- Merkel, Harald Franz Arno, 1966, et al.
(author)
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Quantum Noise in Resistive Mixers
- 2006
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In: 17th International Symposium on Space Terahertz Technology ISSTT 2006.
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Conference paper (peer-reviewed)abstract
- Derivation of the quantum noise of a mixer using second order quantization methods.
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| 20. |
- Merkel, Harald Franz Arno, 1966, et al.
(author)
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Twodimensionally distributed Model for HEB based on Random Phase Transitions
- 2006
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In: 17th International Symposium on Space Terahertz Technology ISSTT 2006.
-
Conference paper (peer-reviewed)abstract
- According to AFM measurements, ultrathin NbN films are not smooth but exhibit a more or less random distribution of microcrystallites. This gives rise to a superconducting to normal conducting phase transition that follows a first order percolation phase transition. Such a phase transition is easily described by a single critical exponent justifying the assumption of a simple, local R(T) curve used in all distributed HEB models.
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| 21. |
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