Search

the dispersion properties of spoof surface plasmon polaritons with 1D rectangular groove structure by analytical solution and numerical solution respectively is analyzed, and the FEM method was used to simulate the refractive index sensing of SPR in terahertz band in an Otto configuration. From the simulation results, we can see that the 1D periodic groove has strong field constraint ability in THz regime as well as in optical band, and the variation of reflection coefficient with incident angle and frequency is very sensitive to the refractive index of the analyte. These results provide a new approach to sample detection and THz regime refractive index sensing, which has great advantages in biomedical tissue detection and sample detection in the future.

In this paper we present a CAD model of optical fibre reflectance probe for biomedical diffuse reflectance spectroscopy applications. Henyey-Greenstein model is used to model the scattering form the biomedical tissue. The CAD model is used to predict the coupling efficiency of the fibre probe with different multimode fibre core diameter and to estimate the separation distance between the probe and the sample for optimized coupling.

We proposed a transcutaneous energy transmission system (TETS) for implantable ventricular assist devices (VADs) in order to improve the quality of life (QOL) of patients. In a conventional TETS, the patient must accurately and tightly fix a rigid coil on his body surfaces because the transmission efficiency remarkably depends on the alignment accuracy of the coil. In order to improve the robustness of the alignment, we proposed a magnetic resonant coupling TETS of long transmission range utilizing flexible coils embedded into clothes. We experimentally evaluated the influence of the coil deformation and biomedical tissue on the transmission efficiency.

In this paper, a wireless power transfer system for implantable medical devices using a miniaturized 3 mm diameter single arm circular spiral antenna is presented. The transmission characteristics, S 21 between the transmitting and receiving antennas with air and tissue as a medium between antennas are analyzed and measured. The receiver antenna receives almost 2 mW average power with power transfer efficiency of 53%. The power transfer efficiency could still reach to 4% with 274 µW average received power, with placement of 1.5 cm tissue and 1 cm air in between two antennas. With one PN diode rectifier, the total DC power from the receiver side is 489 nW.

Microwave tomography (MWT) and ultrasound tomography (UT) are two biomedical imaging modalities which are currently being investigated for applications such as breast cancer imaging. In MWT, the object of interest (OI) is surrounded by a number of antennas that are used to radiate the OI successively with electromagnetic waves in the microwave frequency range. The scattered electric fields are collected at receiver locations surrounding the OI. On the other hand, in UT the OI is surrounded by several ultrasound transducers illuminating the OI by acoustic waves and the scattered pressure from the OI is then collected at the receivers. In both MWT and UT, the scattered data is given to an inverse scattering algorithm to reconstruct specific properties of the object: in MWT the relative permittivity and conductivity (or complex permittivity) of the OI are reconstructed, whereas in UT the complex compressibility and inverse density are reconstructed. Both are quantitative imaging methods and thereby provide some insight into type of tissue corresponding to a pixel value in the image.

OCT is a high speed, high resolution imaging technique which is mostly used for ophthalmology & biomedical tissue imaging. This paper describes the mathematical modeling, simulation & signal analysis of Time-Domain OCT (TD-OCT) & Spectral-Domain OCT (SD-OCT) systems. Using this simulation model, user can enter their OCT system parameters such as center wavelength, bandwidth of the source, power of the source, responsivity of the detector to get the simulated signals of OCT systems, which can be used for further analysis. This mathematical modeling provides an environment for OCT parameter evaluation and OCT signal simulation for different configurations of OCT systems. With the use of this simulation one can predict the output of their OCT system.

Magnetic induction tomography (MIT) in vivo is to reconstruct conductivity of biomedical tissue by coil sensors which are imposed alternating current as well as detecting signals induced by tissue around the coils. In addition to the secondary signals due to tissue parameters, the resulting signals also include the primary field signals contributed by excitation coils which are approximately 5 times orders of the secondary signals. This not only reduces measurement precision, but also affects reconstruction image resolution. Optimization coil sensors can cancel primary field greatly at source. The paper presents coil sensors arrangement suitable for Biomedical magnetic induction tomography. Relative position between the excitation and detection coils was adjusted to reduce the primary signals in resulting signals. Simulation was performed from single-channel to multiple-channels system. The measurement results of all the systems suggest that the signal due to the primary field can be reduced individually at the operating frequency of 10Mz.

The acoustic field in an inhomogeneous medium can be expressed as the sum of incident and scattered parts, and different approximations are used to find the scattered part. We have previously considered the phase corrected scattering integral (PCSI) approach for the field within and near to midscale inhomogeneities with sound speed variations. The PCSI with a simple ray model used to find the phase correction gives good results in cases far beyond the limits of the Born approximation. In the present study we first examine the behaviour of the PCSI approximation in the far field, and compare it with a Kirchhoff (lumped phase) approximation. We then consider media with both sound speed and density variations, and show that the scattering integral can be recast into a form that allows the PCSI method to effectively calculate the contribution due to each effect separately. Comparison with exact results shows that the PCSI is remarkably accurate. We conclude that the PCSI method is effective for estimating the acoustic field in biomedical tissue, with characteristic weak scattering and irregular geometry.

In neurosurgery, delineation of tumor boundaries during resection of brain tumors is of substantial relevance. During operation distinction between tumor and healthy tissue rely on the abilities of the surgeon based on visual and tactile differentiation. In this paper a high sensitivity actuator-sensor system using a piezoelectric bimorph is presented. Frequency shift and transfer function of the bimorphpsilas voltages are detected and evaluated. Sensorpsilas sensitivity is evaluated using two frequency controls strategies: A phase-locked loop (PLL) and a self-oscillating circuit. Results of measurements conducted on gel-phantoms are presented and discussed.

The present study concerns a non-invasive technology used to measure blood components such as glucose and lipids, which are measured for use in daily living. This measurement technology initially measures a two-dimensional near-infrared spectroscopic image that covers only a limited depth below the skin, then processes the image in order to extract the vascular territory. Subsequently, the technology chooses the spectroscopic characteristics of a single vascular territory in order to obtain the blood glucose level and other data through component analysis. This technology is capable of obtaining the spectroscopic characteristics of a single vascular territory, with the measurement of only the proximal skin surface, which is little affected by diffusion caused by biomembranes. This paper describes an image-producing Fourier spectroscopy, which we propose as a measuring technology that can be applied to three-dimensional spectroscopic images.

A useful method for transferring mask patterns over large distances using ion milling is described. This technique exploits the anisotropy of a collimated ion beam to etch the projection of a stencil mask pattern into a thin film. This method avoids the difficulties associated with photoresist processing on highly nonplanar substrates, and thus provides an alternative process avenue for the development of three-dimensional microstructures. The technique is demonstrated by fabricating arrays of high aspect ratio barbs, which are intended for use in tissue fasteners in biomedical applications. >