Entwicklung neuartiger integrierter Terahertz-Systeme, die auf biomedizinische Anwendungen, Astronomie, Kommunikation und andere Bereiche ausgerichtet sind. Beispiele für Themen unter Forschungsbereich 3:
In the DFG research project TIEMPO, an I/Q transceiver for spread-spectrum radar operating in the frequency range from 220 GHz to 420 GHz is researched. This would correspond to a record bandwidth of 200 GHz. Based on the idea of the frequency modulated continuous wave (FMCW) comb radar, a new concept is studied that can be viewed as a digital radar counterpart to a frequency comb radar. To achieve the very wide bandwidth, a novel system architecture implementing a “chess-board spectrum division” will be investigated. Thanks to an elegant system level solution, a single oscillator at a fixed frequency is sufficient to generate five local oscillator (LO) carrier frequencies to cover the entire bandwidth. Furthermore, due to the high-speed I/Q mixed-signal components in combination with the “chess-board” concept, we reduce the number of required transmit/receive channels by two. The wide bandwidth imposes difficult challenges at the circuit design level:
I/Q data converters with 7-bit resolution, 20 GHz bandwidth, and 40 Gbps data-rate
I/Q transmitter and receiver operating above 400 GHz
LO signal generation to cover the entire bandwidth
On-chip antennas with 200 GHz bandwidth and high efficiency
To prove the concept, advanced semiconductor technologies, such as 22 nm FD-SOI (Fully-Depleted Silicon-On-Insulator) CMOS of Globalfoundries is considered. The operation frequencies are close or above fmax of available semiconductor technologies. This requires novel circuit and system level analyses and approaches to circumvent technology limitations. To our knowledge, this is the first digital spread-spectrum radar transceiver concept proposed in this frequency range, and the first operating over a bandwidth of 200 GHz.
The main goal of the project is to utilize the combination of Terahertz quantum-cascade lasers (THz QCLs) with field-effect transistor (FET)-based THz devices for both power detection and as heterodyne receivers, at the target frequencies 2.0, 3.5 and 4.7 THz. These frequencies correspond to the emission lines of several gases which are of utmost importance for atmospheric and deep space research( e. g., O, OH, CO, NO, HO2) and do not have spectral features in the more readily accessible millimetre-wave band.
The use of the selected technologies is justified by the facts that THz QCLs represent compact yet powerful narrowband sources of radiation in 1-5 THz band of electromagnetic spectrum and University of Leeds occupies the leading position in its production. However, due to the lack of suitable detector or mixer technology for integration with laser source, the scope for QCL operation outside of specialized laboratories was limited. Fortunately a suitable solution in the form of FETs has emerged. FETs are rather easy to fabricate, can be obtained through collaboration or commercially, and are suitable for integration with QCLs to form compact spectroscopic systems. In addition, over a decade Goethe-University Frankfurt has gathered a broad expertise in developing and fabrication of these elements which happens to be of a great advantage for the current mission.
One of the main goals of the project is to provide the first compact, ultrafast and narrowband TeraFET detectors in 2 – 5 THz band, possessing a state-of-the-art noise-equivalent power ≤ 100 pW/√Hz up to 3.5 THz with directivities not lower than 16 dBi. As a result, we will be able to develop the first THz gas spectroscopy instrumentation capable of time-resolved narrowband analysis through the use of an integrable FET THz detector.
Emerging around the year 2000, THz bioanalytic techniques have become a strongly growing field of research, since many biomolecules and biomolecular complexes show a rich and relevant intra- as well as intermolecular resonance spectrum in the THz regime [1-3].
The MATISSE project aims beyond individual biomolecular detection, towards the THz analysis and detection of more complex entities and complexes at the root of intercellular signaling and disease propagation: vesicular structures. Vesicles are found inside the cell transporting contents to the outside but also extracellularly as so-called exosomes. These exosomes are cell-to-cell transit systems in the human body with pleiotropic functions in the focus of recent research interest (cf. ). Exosomes are excellent non-hazardous model systems for potentially dangerous viruses, that also belong to the group of vesicles, like e.g. SARS-CoV2.
All these small biological structures (viruses, exosomes) carry and present marker molecules on their surface, by which specific detection is possible. However, detection is still time consuming, requiring advanced biomedical techniques and appropriately trained professionals. To exemplify this using the current problem of SARS-CoV2: Highly specific and sensitive detection is currently only possible by an indirect, time consuming technique, the detection of viral RNA after reverse transcription and amplification by PCR. Faster tests focus of the detection of a viral protein; however, these are known to be less sensitive and specific.
In the MATISSE project, a microfluidic THz biochip with integrated active electronic read-out will be developed for the fast and reliable detection of exosomes and virus particles with high specificity. Our distant aim is that body fluids, potentially carrying virus particles, will pass through the microfluidic THz biosensor and said virus particles are kept by an antibody against structures on their surface (e.g., the Spike protein in the case of SARS-CoV2). After accumulation of potentially present particles, these are detected via THz technology. Sufficient positive and negative controls will make a selective distinction and quantification possible, apart from simple yes/no answers.
 A. Markelz, et al., “Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz,” Chem. Phys. Lett. 320, pp. 42–48, 2000.
 M. Walther, et al., “Far-infrared vibrational spectra of all-trans, 9-cis and 13-cis retinal measured by THz time-domain spectroscopy,” Chem. Phys. Lett. 332, pp. 389–395, 2000.
 R. J. Falconer et al., “Terahertz Spectroscopic Analysis of Peptides and Proteins,” J Infrared Milli Terahz Waves 33, pp. 973–988, 2012.
 R. Kalluri et al., “The biology, function, and biomedical applications of exosomes,” Science 367, 2020.
Prof. Anja katrin Bosserhoff, email@example.com,
Prof. Bhaskar Choubey, Bhaskar.Choubey@uni-siegen.de
Prof. Peter Haring Bolívar, firstname.lastname@example.org
Dr. Anna Katharina Wigger, email@example.com
Merle Richter, PhD Student, firstname.lastname@example.org
Yannik Loth, PhD Student, email@example.com
The ultimate goal of this project is to develop the first THz time-domain spectroscopy system (THz-TDS) for space applications. The envisioned THz system shall operate in the frequency range between 0.3 and 30 THz with a resolution of 100 GHz. It shall be based on a novel THz emitter, a novel THz detection scheme and shall have a maximum degree of photonic integration. The building blocks and their underlying concepts are chosen based on the following features: (i) They are photon-efficient and compatible with those femtosecond fiber lasers that are currently developed for operation in space. (ii) They can match the requirements of space applications such as compactness, minimal weight, minimal power consumption, radiation hardness, robustness against temperature and vibrations.
The current project should be seen as the first of two phases. In phase 1, we plan to work on the verification of fundamental concepts leading to proof-of-principle hardware components on the so-called breadboard level. In phase 2, a follow-up proposal within this SPP, we plan to develop a demonstrator device for a specific use case based on fully chip-integrated components.