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Publication Access status: Open Access , Nonlinear Amorphous Silicon Photodetectors for Distance Ranging(2026)Imaging is a leading instrumentation technique for a vast range of applications. Among others, it is used for scene recognition in autonomous driving, robotics, the medical sector and in smartphones. Besides classical color imaging of two-dimensional (2D) planes, precise and accurate distance ranging is one advancing imaging modality, expanding imaging towards three dimensional (3D) depth sensing. Beyond image quality, high density integration of these image sensors into miniaturized systems, even on a single chip, is a major driver of ongoing development. State-of-the-art distance ranging and 3D imaging techniques are Time-of-Flight (ToF) and Triangulation. Both techniques face challenges in terms of small scale integration capabilities. Typical triangulation-based systems require a specific baseline distance in the cm-range, which is not suitable for monolithic chip integration. ToF-systems can be integrated on a single chip, but its principle requires high precision timings in the sub-ns range, advanced beam steering or complex circuity. Here, developments and achievements on photodetectors based on hydrogenated amorphous silicon (a-Si:H) capable for distance ranging and future 3D imaging are presented. The a-Si:H manufacturing technology at temperatures < 300°C is compatible with the standard CMOS. This approach enables the integration of sensors directly on top of a chip in the back end of line with high geometrical fill factors. The distance ranging operation exploits the nonlinear device behavior with respect to the optical excitation scenario. Based on simulations and subsequent experimental validations, two nonlinear mechanisms and their respective physics are systematically investigated, analyzed and developed towards individual distance ranging techniques. The a-Si:H Focus-Induced Photoresponse (FIP) measures nonlinear current response variations originating from an amplitude-modulated monochromatic optical excitation. The distance is acquired by a frequency selective readout of the nonlinear, focus-dependent sensor signal. Distance resolutions down to 540 μm are achieved, allowing for precise ranging at low measurement and integration effort. The a-Si:H Intrinsic Photomixing Detector (IPD), utilizes an envelope mixing process of two amplitude modulated optical excitations. Thereby, the Time-of-Flight information is transferred to a lower frequency domain, enabling a read-out. This mixing takes place intrinsically within the detector and decreases the measurement complexity. Distance measurements are shown at > 70 m with depth resolutions down to 23 mm, which is comparable with commercial systems. Developments on advanced device concepts are studied and discussed. These concepts systematically improve the sensitivity, spectral bandwidth and speed of the detectors.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:135 5 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Terahertz-Biosensorik: Metamaterial-basierte THz-Sensoren für biomedizinische Anwendungen(2023)Weisenstein, ChristianThe COVID-19 pandemic has shown that rapid and sensitive test methods for the detection of viruses and biomolecules are important tools in medical laboratory diagnostics. With the dynamic development of the infectious event and great efforts in research and development, enormous progress has been made in the field of mRNA vaccine development and in the introduction of personalized testing methods, from which classical analytical methods could also benefit. However, it has become impressively clear that conventionally used laboratory-based diagnostic methods are complex and time-consuming processes that constitute a major challenge for medical care in the dynamic environment of a pandemic. Thus, it is becoming increasingly apparent that new analytical tools with increased analytical speeds and expanded application ranges need to be developed to advance future understanding of disease mechanisms or drug action. Due to the existence of biomolecular resonances in the terahertz (THz) frequency range, there has been a great interest in studying biomolecules using THz technologies since the 2000s. The use of field-enhancing structures such as metamaterials can significantly increase their sensitivity, giving THz biosensors the potential to reach physiologically relevant concentration ranges and thus making them promising candidates for the development of new testing methods. This work presents a THz sensor based on metamaterials in the form of a complementary split ring resonator (CSRR) developed for biomedical applications. The CSRR produce a sharp resonance in the transmission spectrum, which is shifted to a lower resonance frequency in the presence of a dielectric loading. This mechanism can combine the advantages of existing classical THz analyses, such as label-free and rapid detection of biomolecules, with a significant increase in sensitivity and selectivity. In addition, the biosensor can be specifically adapted for the detection of a biomolecule by scaling the geometric dimensions. The polarization properties of the biosensor also allow the additional integration of microfluidic structures for measurements in liquid environments. These are fundamentally challenging for THz analyses due to the high absorption in water, requiring the use of thin liquid films or microfluidic structures. In this work, an extremely high sensitivity of the THz biosensor in the detection of complementary DNA (cDNA) samples obtained from the human melanoma cell line MIA is demonstrated compared to previously published results, but without performing a usually required amplification of the DNA (polymerase chain reaction, PCR). Further experiments also demonstrate that the shift in resonance frequency differs for single- and double-stranded DNA and is also dependent on the resonance frequency of the sensor. A detailed review of biomolecular THz analyses in liquid environments is provided, and a conceptual development and analysis for studies using metamaterial-based THz biosensors with analytes in liquid environments is presented, describing the introduction of a microfluidic structure integrated into the substrate. In addition, the development of measurement technology and design concepts necessary for the realization of THz biosensors is described in detail. Finally, the potential for the development of metamaterial-based THz biosensors is discussed and an outlook for possible future developments is given.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:105 11 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Realisierung einer Graphen-basierten plasmonischen Antenne zur Kommunikation im THz-Bereich(2020)Today’s digitalization is largely made possible by connecting digital components and increasing computing power. This has led to applications and research in the last decades that were previously not possible due to the lack of computing power. These include autonomous driving, deep learning and artificial intelligence. The constant technical progress described by Moore’s Law can be traced back to the miniaturization of components such as transistors. This increases the density of transistors on a processor core and thus its computing power. However, further compliance with Moore’s Law and thus digital progress cannot be achieved in the future by reducing the size of the components alone. Already today, fundamental physical limits are being reached, such as heat dissipation, which make further miniaturization very difficult. Therefore, alternatives are needed to further increase computing power in the future. One possibility is massive parallelization. Here hundreds to thousands of cores are connected in parallel to increase the computing power. However, classical on-chip communication methods such as BUS systems are unsuitable for communication between the cores, as they are only scalable to a limited extent. An alternative is wireless communication, as a key technology for complex architectures. In addition to scalability, this communication technology also has the possibility of reconfiguration and adaptation to current requirements and is therefore perfectly suited for agile network architectures. For this purpose, each core requires an antenna to send signals and receive signals from other cores. The size of the antenna plays a decisive role here, because miniaturization has made the space on a core very precious. Classical metal antennas emitting at one THz have a length of approximately 7000 transistor channels and are therefore far too large. With graphene, on the other hand, there is a fundamentally altered relationship between antenna length and resonance frequency due to the unique material properties. This means that graphene antennas can be up to two orders of magnitude smaller than metallic antennas at the same resonant frequency. The integration of graphene antennas into integrated circuits is therefore ideally suited to realize on-chip communication and thus increase computing power. The research, description, realization and investigation of these antennas is the content of this thesis. The introduction is followed by the theoretical principles for the description of these antennas. Here, first some important antenna fundamentals are explained and then the fundamental descriptions of plasmons are presented. This is followed by a description of graphene. The chapter concludes with the theoretical treatment of plasmonic graphene antennas. After considering the current state of research, the measuring and manufacturing methods are explained. First of all, lithography, which is used to manufacture the antenna structure, is discussed. The next point is the description of the TDS measurement setup used to measure the antennas. Next, theoretical considerations and calculations on the material requirements of graphene follow. The length of the antenna is of crucial importance. Here it is shown that for a functional graphene antenna a good match between antenna geometry and material quality is required. During the technological realization, after some challenges, a stable manufacturing process could be established. For the characterization of graphene different methods are considered. For this purpose needle measurements on the SEM, TDS transmission measurements and Raman spectroscopy are suitable. After the production and characterization of graphene, the dipole antennas are measured in the TDS test setup. The first measurements show that, in addition to the antenna effect, charge carriers accelerated by an electrical bias voltage also contribute to the THz emission. To minimize the influence of this effect, antennas were manufactured and measured in an alternative geometry (H-structure). A clear influence of graphene on the amplitude of the emitted THz radiation was found. The origin of this signal is the concentration of the electric field created by the bias voltage between the antenna arms. These measurements show the first THz emission of a graphene antenna structure. In order to increase the material quality, samples were produced where either one or both sides of the graphene antenna are covered with hBN. Measurements on these antennas show a significantly increased THz emission due to the concentration of the electric field between the two antenna arms. Finally, various possibilities to increase the emission of the graphene antenna are presented. There are possibilities to change the sample setup and geometry as well as external influences like doping and temperature. The final conclusion is followed by a critical discussion of the theoretical and practical results of this work and a classification into possible fields of research and application. This work shows the first THz emission of a graphene antenna structure and provides detailed theoretical, technological and experimental results, which are needed to realize a functional graphene antenna.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:98 7 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Entwicklung von modellbasierten Methoden zur Bestimmung von Materialeigenschaften im THz-Bereich(2017)The determination of the specific material parameters for a sample-substance is the foundation of many scientific, industrial and engineering techniques used for material analysis and recognition. Based on these characteristic features, the comparison and classification of substances can be performed, as well as the derivation of the underlying physical mechanisms and further material properties. The extraction of these material parameters from spectroscopic investigations in the terahertz (THz)-range provides several advantages. Many substances relevant to material analysis display unique absorption characteristics in this frequency-range, which lies between the sections of infrared and microwave radiation in the electromagnetic spectrum. Furthermore, THz-radiation is weakly absorbed by typical packaging materials like textiles, plastics or paper, which are mostly opaque in the optical range of the spectrum. This enables the analysis of substances encapsulated in those materials and of respective composite systems, without relying on measurement techniques that employ ionizing radiation (e.g. x-rays). THz time-domain spectroscopy is one of the most common measurement methods that provides the spectral data from which the material parameters, such as the complex refractive index or complex conductivity, can be extracted. Those systems provide amplitude and phase information, unlike techniques based on power detection that only offer intensities, and at the same time enable broadband measurements. With the continuous development of novel materials and composites, improved fabrication techniques and the steady evolution of THz-systems, new fields of application for the investigation of material parameters in the THz-range frequently arise. At the same time, it becomes apparent that many classical state of the art methods used for handling and extracting material parameters from the spectral measurement are reaching their limitations. They operate increasingly erroneous and can therefore not be applied unconditionally anymore. Four of these scenarios are discussed in this work. The existing methods are evaluated in the context of the particular application and the reasons for their restrictions are determined. Based on these findings new and enhanced methods for the determination and processing of material parameters are developed, validated and assessed. For the first application case it is shown, that the designed recursive propagation model allows the description and analysis of multilayered sample systems of arbitrary thicknesses. In contrast to this, the classical approaches fail in instances of solely thin layers or combinations of thin and thick layers, since they cannot correctly represent the multiple internal reflection inside the layered structures. In the second case it is demonstrated, that the modelling of material parameters is not limited to predict the transmission properties of different material samples. Using the introduced technique, they can also be utilized to determine the system requirements that are necessary to analyze such samples. The evaluation of the conductivity of thin layers, e.g. of graphene, is the third application scenario. Here, the utilization of the developed expanded thin-film approximation avoids the systematic errors that are introduced into the calculated sheet conductivities by the typical form of the approximation. Consequently, the material parameters derivable from this sheet conductivity, like the relaxation time and the chemical potential, can be determined without the effects of these errors as well. In the fourth case, the determination of material parameters from samples with strong absorption characteristics by model-based methods is demonstrated. It is shown that material parameters with a three orders of magnitude lower mean square error, compared to the respective frequency-domain approach and the classical concept without a material-model, can be achieved by the utilization of the developed material-model-based time-domain method. Furthermore, it becomes apparent that this robustness of the time-domain method could be maintained, even if wide segments of the absorption features lie bellow the noise-floor. The developed methods thereby allow overcoming the various existing limitations of the standard approaches used for the determination and evaluation of material parameters in the THz-range. Hence, the investigation of sample scenarios that were previously not accessible becomes feasible. Moreover, future fields of application of the THz-material analysis can thereby also draw on, and be built upon a more versatile set of methods and procedures.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:81 7 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , On-wafer characterization of mm-wave and THz circuits using electrooptic sampling(2016)THz, the electromagnetic spectrum lying between millimeter waves and optics, is nowadays widely utilized in the applications such as material inspection, medicine, explosives detection and astronomy. Although optical and photonic based systems for generating THz waves can fully cover the upper band of the THz spectrum (from several THz to far infrared), they are inefficient at lower frequency bands i.e., mm-waves, and at the same time inappropriately bulky for portable applications. In contrast, recent progress in solid states electronics in conjunction with aggressive scaling of devices are promising to facilitate the future availability of THz systems realized as compact and cheap all-electronic solutions. THz microelectronics is an increasingly relevant field of activities, therefore. Without concerning about the challenges in the design and fabrication of such devices, their performance needs to be characterized with systems faster than the device itself; therefore, we face with limitations. Recently, the measurement bandwidth of microwave network analyzers equipped with extension modules has extended beyond 1 THz. However, their calibration is a challenging task and performing a full band measurement, due to a need for waveguide components, considerably increases the cost and time of measurement. Systematic errors in system calibration due to lack of precise models for devices at THz frequencies are also remarkable drawbacks of this approach. An eligible alternative for these systems is the use of electrooptic and photoconductive sampling which rely on optical and photonic approaches. These techniques with the help of femtosecond pulse lasers provide a very broadband measurement system far beyond today’s electronic devices bandwidth without suffering from the challenges of the electronic approach. In particular electrooptic sampling with non-contact probing can also perform useful high resolution near field scanning of devices. The aim of this thesis is to demonstrate the electrooptic sampling for the characterization of mm-wave and THz electronic devices. To this end, an extremely broadband (microwave to THz) device, which is a 65-nm CMOS nonlinear transmission line (NLTL), is used as the device under test. Before showing the measurement results for this device, the advances in THz electronics as well as their common the characterization techniques are reviewed. For the characterization, a rather compact EOS experimental setup featured with a large dynamic range, high sensitivity and high spatial resolution is presented. In the measurement phase, it is shown that what challenges in particular for the characterization of a nonlinear device we may face to and which scenarios can be used to overcome them. The relative jitter in EOS, known as the most prohibiting factor for achieving a high measurement bandwidth, is resolved with a novel synchronization technique called Laser Master Laser Slave (LM-LS). This is achieved by feeding the DUT with a microwave signal which is generated from the comb harmonics of the femtosecond laser. Since the signal is sampled by the laser itself, EOS provides a fully coherent heterodyne detection which helps to significantly increase the detection bandwidth of the system from 50 GHz up to 300 GHz which is presently restricted by the DUT fabrication technology i.e. the 65-nm CMOS. Furthermore, it is shown that for nonlinear devices, measurement with EOS can outperform traditional microwave network analyzer measurements and in particular it can detect hidden features like conversion losses which may not be observed by electronic techniques. In the end by performing photoconductive measurements for the DUT, a good comparison between electrooptic and photoconductive sampling in terms of their detection bandwidth and image resolution is demonstrated.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:71 6 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Integrale Betrachtung zur systematischen Definition von 3D Bildgebungssystemen in der Produktionstechnik(2016)Machine vison systems are suitable in many areas of production in the industrial manufacturing. As well 3D-machine-vision-systems are used as solution for diverse problems in manufacturing engineering. The area of possible application ranges from simple tasks for quality control or manipulation and handling to complex security relevant issues. On account of its continued development and the diversity of applicable methods in the field of machine vision, the project planning of 3D machine-vision-application is a challenging task. The problem with the integration of 3D-vision-systems is the big variety of possibilities to solve problems in plant automation by means of machine-vision methods. This thesis describes the development of a method for the efficient project planning and design of 3D-machine-vision-systems in the field of special machine construction. First the influence variables effecting the vision-system are determined, which are arising from the task, the production process and the periphery of the process. Based on these characteristics a methodical approach is defined. This approach enables developers of production facilities to define the specific measures for implementing an effective and efficient machine-vision-setup, which is well integrated in the production process. The approach of this thesis is an analytical observation to describe the formalities of the selection of imaging sensors and how this decision is influencing the further project planning and evaluation procedure. In the context of example application, the application of the approach is presented explicit. Furthermore, object-oriented methods are investigated regarding their ability to gather all relevant features of a 3D-machine-vision system in the field of plant automation and special machine construction. Both aspects concerning the production and problems of machine vision are described universally. In conclusion, the potential of this approach is discussed and an evaluation of possibilities and further development is given.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:61 10 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Terahertz-Biosensorik : dielektrische long-range Moden für die THz-Analyse von Biomolekülen in stark absorbierenden Flüssigkeiten(2015)In certain parts of the world medical care has probably never been better than it is now. Yet, in highly industrialized countries a growing number of people suffer from serious lifestyle diseases like diabetes, cardiovascular disease, various forms of cancer, dementia and Parkinson’s or Alzheimer’s disease. A great variety of bioanalytical tools is available for detecting such diseases at the molecular level. These diagnostic methods are essential for deciding on effective treatment at the earliest stage possible. Nevertheless, the overall intricacy of biochemical processes is rarely understood at a comprehensive level due to the vast physiological complexity of the human organism. One of the greatest challenges of our times is discovering disease-related disorders within the biomolecular context. As a result of recent advances in THz technologies and deeper insights into molecular resonances at THz frequencies, the THz community has begun to investigate (patho-)physiological significant analytes in the THz frequency range. In order to take the full complexity and functionality into account, analytes need to be studied in native, aqueous environments. Since THz radiation is strongly absorbed by water, traditional THz setups usually only allow for biomolecular characterization in aqueous environments under non-physiological conditions. Possible solutions to overcoming these experimental limitations will be neither simple nor quick, and none are widely available at the moment. Therefore, the THz community presently needs to develop novel strategies and schemes to make substantial progress in THz analysis of biomolecules under physiological conditions. This thesis presents the systematic development of an alternative technological platform suitable for the THz-based recognition of biomolecules in aqueous solutions. Within the scope of this sensoric approach THz waves are coupled as long-range guided modes into µm-thin liquid films. The excitation as well as the propagation along cm-range distances will be clearly demonstrated. In comparison to the strong THz absorption in bulk water, this waveguiding approach allows for a frequency dependent increase in the interaction distance by up to four orders of magnitude between THz radiation and water. The feasibility of the mode for THz sensing will be demonstrated in an exemplary fashion through the detection of the protein bovine serum albumin. Moreover, analytically modelled resonating Bragg structures will demonstrate the potential suitability of the long-range guided mode scheme for significantly increasing sensitivity capabilities. This thesis then, presents a comprehensive approach that can function as a basis for prospective THz detection and characterization of biomolecules at physiological concentrations. This is a decisive step for advancing THz sensing under physiological conditions.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:54 9 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Terahertz-Erkennung energetischer Materialien : spektroskopische Analysen und technologische Perspektiven bildgebender Systeme(2014)In recent years, there is a growing demand for technology to identify and recognize materials relevant to security. The terahertz (THz) frequency range, situated between microwaves and infrared in the electromagnetic spectrum, has certain properties making it predestined for security applications. Many materials, e.g. energetic materials (explosives), exhibit resonant absorptions, so called spectral fingerprints, in the THz-frequency range which facilitate their recognition. In combination with the transparent nature of many clothing- and packaging materials to THz-radiation, the application of THz-technology for the recognition of hidden explosives is obvious. In order to successfully recognize energetic materials with THz-technology, requirements in two areas have to be fulfilled, namely suitable THz-technologies for material detection and detailed spectroscopic THz-analyses of energetic materials. This thesis investigates both areas by evaluation of suitable detector technologies for THz material recognition as well as an analysis of spectroscopic experiments on a selection of interesting energetic materials. THz time-domain spectroscopy setups in transmission and reflection, which where developed in the context of this thesis, are used to analyze the energetic materials. Spectroscopy in transmission mode, facilitating a very high bandwidth from 0,2 - 6,6 THz, is used to determine the absorption-coefficient as a quantitative measure and enabled the author to measure a clear resonance of the explosive RDX at 4,2 THz for the first time. The variability of spectral fingerprints due to additives, inhomogeneities and preparation of explosives are investigated via THz-spectroscopy. Results show that an inhomogeneous broadening of a resonance can occur due to the preparation of the energetic material. This is a challenge for THz-based recognition of explosives. Furthermore, several THz-imaging technologies are investigated regarding their respective potential for THz explosives recognition. A realtime THz-imaging system based on a row of 32 sub-harmonic mixers, developed in cooperation with project partners, as well as a system based on uncooled antenna-coupled thermocouples, both operating at 800 GHz, are characterized. THz-imaging on objects relevant to security is demonstrated using different THz-imaging technologies. The outcome of THz-imaging of samples of explosives is their recognition based on resonant absorptions using different THz-imaging technologies. In this thesis, the THz-recognition of resonances of explosives using thermocouples as the THz power detector is demonstrated globally for the first time. To conclude, the potential of the THz-recognition of energetic materials is discussed and an assessment of future directions for research is given.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:42 7 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Entwicklung eines Sensorsystems zur kontinuierlichen Ölqualitätsmessung und Verschleißidentifikation in Getrieben und anderen Aggregaten(2012)An oil sensor system for the continuous, online measurement of oil quality has been developed using the quality dependent parameters, electrical conductivity and permittivity. The sensor system permits the evaluation of the ‘total machine system’ by the basic approach of measuring the changes and degradation in the oil system. Warnings of critical operating conditions, such as excessive wear or lubricant acidification and also accurate indication of the need for preventive maintenance are realised. The rolling of bearings on the raceway can cause localised friction stress, resulting in the formation of sharp edged, brittle, hairline cracks. Often these are caused by only briefly prevailing conditions, e.g. high wind gusts in wind turbines. This crack formation is the first stage in the failure mechanism commonly associated with early failure of the machine. Practical measurements and calculations employing the laws of Maxwell-Garnett, Lichtenecker and Piekara support this hypothesis. Promising applications include industrial drives, wind turbines, marine gearboxes, turbines and engines, hydraulic systems and transformers. Benefits include increased uptime, reduced maintenance and an improvement in both economic and environmental efficiency. More effective utilization of machines, targeted prevention, increased serviceable life and reduced downtime are thereby realised.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:31 6 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , A high-sensitivity THz-sensing technology for DNA detection with split-ring resonator based biochips(2012)The detection and characterization of dielectric thin-films and biomolecules are of great interest for THz-research due to characteristic material properties at these frequencies. The detection of films much thinner than wavelength or material amounts in femtomol range requires specialized sensors. The sensors identify a material's permittivity, or refractive index, respectively, by a signal delay in the time domain or the detuning of a resonator in the frequency domain. A biochip in particular aims at the detection of sub-μm-size molecules, such as DNA or proteins. This work begins with a review of the state-of-the-art THz-thin-film sensing approaches evolving towards lower film thicknesses. These indicate that more promising results are achieved with high-Q resonators due to their more efficient sample/E-field interaction. The asymmetric double-split ring resonator (aDSR) is researched, exhibiting a sharp resonance feature and a strong concentration of the electric field. In a two-dimensional array, corresponding to a frequency selective surface, the aDSR qualifies as the basic element for a biochip with a high sensitivity. For the biochip development material properties as well as practical and commercial aspects are taken into account. The result is a glass chip with a structured three-layer metal surface and undercut edges. With regard to practical aspects, a biochip reader is developed being compact, easy to use, of low-maintenance and affordable, to find application in biomedical laboratories. The reader is essentially a fully-electronic spectrometer for 240 - 320 GHz, reading a single measurement spot in 110 Milliseconds. Compared to a classical network analyzer, the setup has reduced complexity and cost. It generates the high frequencies from a single voltage controlled oscillator by upconverting in diode-based mixers. Heterodyne detection is realized by utilizing the time delay of the signal sweeping through the frequency band. The functionality of biochip and reader is compared to TDS measurements proving good results. The detection of dielectric thin-films is successfully applied with dye, photo-resist and gelatin. Hybridized DNA, deposited locally by a functionalization process, is detected. However, the DNA detection could not be confirmed by additional measurements. Causes for this failure are investigated and discussed.Source Type:Doctoral ThesisSeries:Höchstfrequenztechnik und QuantenelektronikVolume number:2755 581
