Dielectric loss occurring in tissues in close proximity to UHF implanted antennas is an important factor in the performance of medical implant communication systems. Common practice in numerical analysis and testing is to utilize radiation efficiency measures external to the tissue phantom employed. This approach means that radiation efficiency is also dependent on the phantom used and antenna positioning, making it difficult to understand antenna performance and minimize near-field tissue losses. Therefore, an alternative methodology for determining the intrinsic radiation performance of implanted antennas that focuses on assessing structural and near field tissue losses is presented. The new method is independent of the tissue phantom employed and can be used for quantitative comparison of designs across different studies. The intrinsic radiation efficiency of an implant antenna is determined by assessing the power flow within the tissue phantom at a distance of at least λg/2 from the radiating structure. Simulated results are presented for canonical antennas at 403 MHz and 2400 MHz in homogeneous muscle and fat phantoms. These illustrate the dominance of propagating path losses in high-water content tissues such as muscle, whereas nearfield dielectric losses may be more important in low-water tissues such as fat due to the extended reactive near-field.

A study of the intra-body propagation channel between two identical tissue implanted antennas is presented. To investigate the effect of the tissue boundaries, the channel between the two implants is evaluated within a tissue layered numerical phantom with both insulated and un-insulated antenna structures in the MedRadio operating band (2.36-2.40 GHz). The results demonstrate how wave propagation between the antennas inside the same block of tissue is largely unaffected by changes in the peripheral surrounding tissues, irrespective of their material characteristics. On the contrary, propagation across tissue boundaries is affected by the boundary and the path distance within each tissue according to the dielectric parameters involved.

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The establishment of an accurate and efficient method for the sensitive detection of protein concentrations in fluids using miniaturized electrochemical sensors is presented. As protein levels in wounds can be utilized to assess the status and severity of a wound and determine the best course of treatment, real time quantification is potentially extremely valuable. The experimental methodology for monitoring protein concentrations using screen printed carbon electrodes (SPCEs) that requires minimal sample size (as small as 80 µL) for each measurement is presented. The technique was modelled and implemented using bovine serum albumin (BSA) concentrations from 0.3 to 30 mg/ml and was used to detect changes in concentration. The results demonstrated a good stability and reproducibility when making measurements on different protein concentrations. This technique was tested and verified using two different types of screen printed carbon electrodes (SPCEs), while both consist of three electrode electro-chemical cell, one has an added Poly-L-Lysine coating to anchor protein and improve efficiency. The objective of this work was to establish for the first time a device with the necessary mathematical model that can be used by clinicians to assess the severity of the wound through measuring the protein concentration.

Abstract-Applications are emerging that feature multiple implanted devices as part of an intra-body network. Establishing high bandwidth communications between such devices is challenging and there is a need to understand the principles of the intra-body channel. This paper presents a numerical analysis of the wave propagation between identical antennas in the MedRadio operating band (2.36-2.40 GHz) within cylindrical three layered tissue equivalent phantoms. The results presented show the effect of dielectric boundaries and different tissue properties on dominant wave propagation paths and link gain which provides essential information for efficient system design.