Ulrik Hanke - Academia.edu (original) (raw)
Papers by Ulrik Hanke
Smart Materials and Structures
Electronics
Inductive and capacitive impedance matching are two different techniques optimizing power transfe... more Inductive and capacitive impedance matching are two different techniques optimizing power transfer in magnetic resonance inductive wireless power transfer. Under ideal conditions, i.e., unrestricted parameter ranges and no loss, both approaches can provide the perfect match. Comparing these two techniques under non-ideal conditions, to explore fundamental differences in their performance, is a challenging task as the two techniques are fundamentally different in operation. In this paper, we accomplish such a comparison by determining matchable impedances achievable by these networks and visualizing them as regions of a Smith chart. The analysis is performed over realistic constraints on parameters of three different application cases both with and without loss accounted for. While the analysis confirms that it is possible to achieve unit power transfer efficiency with both approaches in the lossless case, we find that the impedance regions where this is possible, as visualized in th...
Journal of Physics D: Applied Physics
Applied Sciences
The competition between various carbohydrates in the binding to Concanavalin A (Con A) can be exp... more The competition between various carbohydrates in the binding to Concanavalin A (Con A) can be exploited in gravimetric microsensors that detect changes in mass or viscoelasticity as a function of glucose concentration. Such sensors are based on the immobilisation of Con A as the ligand specific element, and a successful application requires that the binding property of Con A is retained. This paper presents a simplified immobilisation procedure of Con A on a quartz surface, a common material for gravimetric microsensors. Structural assessment with atomic force microscopy confirmed that the surface was covered with a layer of macromolecules. This layer shows the presence of entities of various sizes, presumably monomers, dimers and tetramers among which dimers of the Con A are the most dominant structure. Functional assessment using fluorescent labelled dextran (FITC and Alexa 488) suggests a surface coverage ranging from 1.8 × 1011 to 2.1 × 1012 immobilised fluorescent molecules per...
IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 2018
This paper presents a new approach for the design of film bulk acoustic resonators (FBARs) with h... more This paper presents a new approach for the design of film bulk acoustic resonators (FBARs) with high-quality factor Qa{Q}_{a}Qa at antiresonant frequency fa{f}_{a}fa . Lamb waves are among the main contributors to the loss of energy at fa{f}_{a}fa and the deterioration of Qa{Q}_{a}Qa . The targeted approach is an optimization process of a dual-step frame structure to alleviate the problem with Lamb waves at fa{f}_{a}fa . Such a frame is a combination of two neighboring steps that have different acoustic impedances reflecting the two Lamb modes that carry the largest amount of energy. The dimensions of these steps are computed using the diffraction grating method. To do so, the dispersion curves of Lamb waves and their associated power flows are calculated using a global matrix method and the acoustic Poynting's Theorem. This results in an enhancement in Qa{Q}_{a}Qa of nearly 82% for an FBAR with a dual-step frame in comparison with an FBAR with no frame, as well as a smoother electrical res...
IEEE transactions on ultrasonics, ferroelectrics, and frequency control, Jan 5, 2018
This paper establishes constitutive equations, or linear two-port models, of piezoelectric layere... more This paper establishes constitutive equations, or linear two-port models, of piezoelectric layered beams with interdigital electrodes (IDE). The effect of the non-trivial field on the transduction is analyzed. Based on conformal mapping techniques, we derive a new analytic expression for the capacitance, the electric field and the electromechanical coupling factor of an anisotropic dielectric with the IDE configuration on top. The IDE capacitance with an anisotropic permittivity can be treated as the one with an isotropic permittivity. The complexity expression of the non-uniform field is simplified to a quadratic form. A correction is required for the transducer's coupling constant. All modifications are expressed analytically. The analytic models are verified against the finite element method. Finally, the twoport models help to compare to devices with other electrode configurations such as beams with a top and bottom electrode (TBE).
IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 2018
In this paper, we derive and compare the linear static bending of piezoelectric actuators with tr... more In this paper, we derive and compare the linear static bending of piezoelectric actuators with transversal ( ) and longitudinal ( ) coupling. The transducers are, respectively, structures utilizing top and bottom electrodes (TBEs) and interdigitated electrodes (IDEs). While the theory is well developed for the TBE beam, governing equations for the bending of the piezoelectric beams with IDEs are far less developed. We improve on this by deriving the governing equation for the IDE beam with an arbitrary number of layers and with coupling consistently included. In addition, we introduce a phenomenological quadratic form for the nonuniform field that lets us derive a deflection formula with nontrivial effects of the field accounted for. The theory is applied to derive deflection formulas for both cantilever and clamped-clamped beams. All analytic results are validated with numerical simulations. From the analytic models, two different figures of merit (FOMs) are derived. We show that t...
IEEE Sensors Journal
Mutual capacitance touch screens translate billions of finger touches to digital signals around t... more Mutual capacitance touch screens translate billions of finger touches to digital signals around the world daily. By enabling these screens to detect ungrounded objects, it may be possible to extend their functionality by detecting tangible user interface objects on the screen surface. This article presents results from finite element method simulations, as well as experiments, showing that the mutual capacitance touch screen panel sensing principle can be used to detect ungrounded objects. Looking into how different design parameters of the touch panel affect grounded and ungrounded touch differently, we have found a film-glass-film stack-up to be 1.55 times more sensitive to ungrounded than grounded touch, compared to 0.65 and 0.20 for two different configurations of glass-film stack-up.
Physical Review B
A general expression is given for the change in free energy when a charge tunnels through a junct... more A general expression is given for the change in free energy when a charge tunnels through a junction in a one-dimensional array of N metallic islands with arbitrary capacitances and arbitrary background charges. This is used to obtain expressions for the (average) threshold voltage of the Coulomb blockade for a few characteristic geometries. We find that including random background charges has a large effect on the N-dependence of the threshold voltage: In an array with identical junction capacitances C and gate capacitances Cg, the threshold voltage, averaged over the background charge, is proportional to N a , where a crosses over from 1 2 to 1 when N becomes larger than 2.5 C/Cg.
Active and Passive Smart Structures and Integrated Systems 2016
2016 IEEE International Frequency Control Symposium (IFCS), 2016
Proceedings of Spie the International Society For Optical Engineering, 2006
ABSTRACT
Sensors and Transducers Journal, 2008
In this paper, we are going to present a model of spring constant and pull down voltage for non u... more In this paper, we are going to present a model of spring constant and pull down voltage for non uniform RF MEMS cantilever. In order to reduce the pull down voltage, it is usual to use a beam, which is narrower close to anchor and wider at the end or electrode area for a cantilever. Compare to uniform beam, this beam will have lower spring constant which will reduce the pull down voltage. A comprehensive model for spring constant and pull down voltage of the non uniform cantilever is developed through basic force deflection mechanism of the suspended beam.
2011 11th IEEE International Conference on Nanotechnology, 2011
ABSTRACT SiO2/Si3N4 double-layer dielectric stacks, instead of single dielectric layer, have been... more ABSTRACT SiO2/Si3N4 double-layer dielectric stacks, instead of single dielectric layer, have been investigated to mitigate charge accumulation in the dielectric for the purpose of high reliable capacitive microelectromechanical switch. Two kinds of double-dielectric-layers with different thickness ratios are structured, and SiO2 single-layer dielectric structure is also fabricated for comparison. The charge injection kinetics in the dielectric layer has been investigated by performing C-V measurements on metal-insulator-semiconductor (MIS) capacitor structure instead of an actual switch. The experiment results generally show that low charge accumulation has been achieved by using double-layer dielectric stacks. More in detail, the experiment results further show that the charge accumulation behaviors varied greatly with the different thickness ratio of Si3N4 to SiO2. With same positive dc bias voltage for charge injection, we found that net negative charge accumulated in the thin-oxide MNOS structure and net positive charge accumulated in the thick-oxide MNOS structure as the electron injection is suppressed by the thick oxide. It can be anticipated that the charge accumulation in the switch dielectric can be minimized by optimizing the thickness ratio of double-layer dielectric.
2015 IEEE SENSORS, 2015
Mutual capacitance touch screens are responsible for detecting billions of human fingers touching... more Mutual capacitance touch screens are responsible for detecting billions of human fingers touching them around the world every day. Being able to use such screens for detection of ungrounded objects as well, would make it easier develop compatible tangible user interface objects that could extend the functionality of the screens. We present results from both simulations and experiments showing that the sensing principle used in these screens are able to detect ungrounded objects.
Nanotechnology
We propose a single-electron tunnelling thermometer, based on a parallel array of double tunnel j... more We propose a single-electron tunnelling thermometer, based on a parallel array of double tunnel junctions, which covers the temperature range from about 30 mK to about 4 K. The calibration curve has been derived analytically, and investigated numerically including co-tunnelling. The influence of background charge, which is a material problem, has also been studied.
Smart Materials and Structures
Electronics
Inductive and capacitive impedance matching are two different techniques optimizing power transfe... more Inductive and capacitive impedance matching are two different techniques optimizing power transfer in magnetic resonance inductive wireless power transfer. Under ideal conditions, i.e., unrestricted parameter ranges and no loss, both approaches can provide the perfect match. Comparing these two techniques under non-ideal conditions, to explore fundamental differences in their performance, is a challenging task as the two techniques are fundamentally different in operation. In this paper, we accomplish such a comparison by determining matchable impedances achievable by these networks and visualizing them as regions of a Smith chart. The analysis is performed over realistic constraints on parameters of three different application cases both with and without loss accounted for. While the analysis confirms that it is possible to achieve unit power transfer efficiency with both approaches in the lossless case, we find that the impedance regions where this is possible, as visualized in th...
Journal of Physics D: Applied Physics
Applied Sciences
The competition between various carbohydrates in the binding to Concanavalin A (Con A) can be exp... more The competition between various carbohydrates in the binding to Concanavalin A (Con A) can be exploited in gravimetric microsensors that detect changes in mass or viscoelasticity as a function of glucose concentration. Such sensors are based on the immobilisation of Con A as the ligand specific element, and a successful application requires that the binding property of Con A is retained. This paper presents a simplified immobilisation procedure of Con A on a quartz surface, a common material for gravimetric microsensors. Structural assessment with atomic force microscopy confirmed that the surface was covered with a layer of macromolecules. This layer shows the presence of entities of various sizes, presumably monomers, dimers and tetramers among which dimers of the Con A are the most dominant structure. Functional assessment using fluorescent labelled dextran (FITC and Alexa 488) suggests a surface coverage ranging from 1.8 × 1011 to 2.1 × 1012 immobilised fluorescent molecules per...
IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 2018
This paper presents a new approach for the design of film bulk acoustic resonators (FBARs) with h... more This paper presents a new approach for the design of film bulk acoustic resonators (FBARs) with high-quality factor Qa{Q}_{a}Qa at antiresonant frequency fa{f}_{a}fa . Lamb waves are among the main contributors to the loss of energy at fa{f}_{a}fa and the deterioration of Qa{Q}_{a}Qa . The targeted approach is an optimization process of a dual-step frame structure to alleviate the problem with Lamb waves at fa{f}_{a}fa . Such a frame is a combination of two neighboring steps that have different acoustic impedances reflecting the two Lamb modes that carry the largest amount of energy. The dimensions of these steps are computed using the diffraction grating method. To do so, the dispersion curves of Lamb waves and their associated power flows are calculated using a global matrix method and the acoustic Poynting's Theorem. This results in an enhancement in Qa{Q}_{a}Qa of nearly 82% for an FBAR with a dual-step frame in comparison with an FBAR with no frame, as well as a smoother electrical res...
IEEE transactions on ultrasonics, ferroelectrics, and frequency control, Jan 5, 2018
This paper establishes constitutive equations, or linear two-port models, of piezoelectric layere... more This paper establishes constitutive equations, or linear two-port models, of piezoelectric layered beams with interdigital electrodes (IDE). The effect of the non-trivial field on the transduction is analyzed. Based on conformal mapping techniques, we derive a new analytic expression for the capacitance, the electric field and the electromechanical coupling factor of an anisotropic dielectric with the IDE configuration on top. The IDE capacitance with an anisotropic permittivity can be treated as the one with an isotropic permittivity. The complexity expression of the non-uniform field is simplified to a quadratic form. A correction is required for the transducer's coupling constant. All modifications are expressed analytically. The analytic models are verified against the finite element method. Finally, the twoport models help to compare to devices with other electrode configurations such as beams with a top and bottom electrode (TBE).
IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 2018
In this paper, we derive and compare the linear static bending of piezoelectric actuators with tr... more In this paper, we derive and compare the linear static bending of piezoelectric actuators with transversal ( ) and longitudinal ( ) coupling. The transducers are, respectively, structures utilizing top and bottom electrodes (TBEs) and interdigitated electrodes (IDEs). While the theory is well developed for the TBE beam, governing equations for the bending of the piezoelectric beams with IDEs are far less developed. We improve on this by deriving the governing equation for the IDE beam with an arbitrary number of layers and with coupling consistently included. In addition, we introduce a phenomenological quadratic form for the nonuniform field that lets us derive a deflection formula with nontrivial effects of the field accounted for. The theory is applied to derive deflection formulas for both cantilever and clamped-clamped beams. All analytic results are validated with numerical simulations. From the analytic models, two different figures of merit (FOMs) are derived. We show that t...
IEEE Sensors Journal
Mutual capacitance touch screens translate billions of finger touches to digital signals around t... more Mutual capacitance touch screens translate billions of finger touches to digital signals around the world daily. By enabling these screens to detect ungrounded objects, it may be possible to extend their functionality by detecting tangible user interface objects on the screen surface. This article presents results from finite element method simulations, as well as experiments, showing that the mutual capacitance touch screen panel sensing principle can be used to detect ungrounded objects. Looking into how different design parameters of the touch panel affect grounded and ungrounded touch differently, we have found a film-glass-film stack-up to be 1.55 times more sensitive to ungrounded than grounded touch, compared to 0.65 and 0.20 for two different configurations of glass-film stack-up.
Physical Review B
A general expression is given for the change in free energy when a charge tunnels through a junct... more A general expression is given for the change in free energy when a charge tunnels through a junction in a one-dimensional array of N metallic islands with arbitrary capacitances and arbitrary background charges. This is used to obtain expressions for the (average) threshold voltage of the Coulomb blockade for a few characteristic geometries. We find that including random background charges has a large effect on the N-dependence of the threshold voltage: In an array with identical junction capacitances C and gate capacitances Cg, the threshold voltage, averaged over the background charge, is proportional to N a , where a crosses over from 1 2 to 1 when N becomes larger than 2.5 C/Cg.
Active and Passive Smart Structures and Integrated Systems 2016
2016 IEEE International Frequency Control Symposium (IFCS), 2016
Proceedings of Spie the International Society For Optical Engineering, 2006
ABSTRACT
Sensors and Transducers Journal, 2008
In this paper, we are going to present a model of spring constant and pull down voltage for non u... more In this paper, we are going to present a model of spring constant and pull down voltage for non uniform RF MEMS cantilever. In order to reduce the pull down voltage, it is usual to use a beam, which is narrower close to anchor and wider at the end or electrode area for a cantilever. Compare to uniform beam, this beam will have lower spring constant which will reduce the pull down voltage. A comprehensive model for spring constant and pull down voltage of the non uniform cantilever is developed through basic force deflection mechanism of the suspended beam.
2011 11th IEEE International Conference on Nanotechnology, 2011
ABSTRACT SiO2/Si3N4 double-layer dielectric stacks, instead of single dielectric layer, have been... more ABSTRACT SiO2/Si3N4 double-layer dielectric stacks, instead of single dielectric layer, have been investigated to mitigate charge accumulation in the dielectric for the purpose of high reliable capacitive microelectromechanical switch. Two kinds of double-dielectric-layers with different thickness ratios are structured, and SiO2 single-layer dielectric structure is also fabricated for comparison. The charge injection kinetics in the dielectric layer has been investigated by performing C-V measurements on metal-insulator-semiconductor (MIS) capacitor structure instead of an actual switch. The experiment results generally show that low charge accumulation has been achieved by using double-layer dielectric stacks. More in detail, the experiment results further show that the charge accumulation behaviors varied greatly with the different thickness ratio of Si3N4 to SiO2. With same positive dc bias voltage for charge injection, we found that net negative charge accumulated in the thin-oxide MNOS structure and net positive charge accumulated in the thick-oxide MNOS structure as the electron injection is suppressed by the thick oxide. It can be anticipated that the charge accumulation in the switch dielectric can be minimized by optimizing the thickness ratio of double-layer dielectric.
2015 IEEE SENSORS, 2015
Mutual capacitance touch screens are responsible for detecting billions of human fingers touching... more Mutual capacitance touch screens are responsible for detecting billions of human fingers touching them around the world every day. Being able to use such screens for detection of ungrounded objects as well, would make it easier develop compatible tangible user interface objects that could extend the functionality of the screens. We present results from both simulations and experiments showing that the sensing principle used in these screens are able to detect ungrounded objects.
Nanotechnology
We propose a single-electron tunnelling thermometer, based on a parallel array of double tunnel j... more We propose a single-electron tunnelling thermometer, based on a parallel array of double tunnel junctions, which covers the temperature range from about 30 mK to about 4 K. The calibration curve has been derived analytically, and investigated numerically including co-tunnelling. The influence of background charge, which is a material problem, has also been studied.