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The purpose of this paper is to study the interaction of electromagnetic fields with biological tissues in the presence of antennas implanted subcutaneously for biotelemetry applications. The authors examined the influence of these radiative devices on energy absorption and also their effects as reflective metal surfaces when incoming radiofrequency energy was present.

The research was carried out using electromagnetic modeling based on the finite difference time domain method and the calculations were performed to determine the electric field and specific absorption rate. The implanted antenna operated in the Medical Implant Communication Service band. The incoming external electric fields considered included different frequency bands covering most current telecommunications standards.

Levels of absorbed energy with and without the implanted device.

The paper offers an analysis of results and comparison with current dosimetric standards and guidelines for limiting electromagnetic exposure.

The paper studies the interactions of implanted antennas with biological tissues, taking into account two behaviors: radiative and passive.

The purpose of this paper is to investigate the feasibility of using micro electromechanical systems (MEMS) to convert a binary phase shift keying (BPSK) signal to a simpler amplitude shift keying (ASK) scheme.

The prototype is designed within the SOIMUMPs® fabrication process constraints. The fabrication constraints imposed geometric limitations on what could be tested. These constraints were used to build a mathematical model, which in turn was used to optimize the response using MATLAB®. The optimized design was tested using finite element analysis with CoventorWare®, and finally lab tests on the fabricated device were performed to confirm theoretical predictions.

Theoretical predictions compared well with lab measurements on a prototype device measuring 2.9 mm². The prototype was tested with a carrier frequency of 174 kHz at a BPSK data rate of 3 kHz and carrier amplitude of 6 V. With these parameters, ASK modulation indices of 0.96 and 0.94 were measured at the two output sensors.

This study provides a MEMS solution for BPSK to ASK conversion. The study also identifies what limits betterment of the modulation index and data rate. Such a device has potential application in wireless sensor network (WSN) nodes that have energy harvesters and sensors that are also built in MEMS. Being a MEMS device, it can facilitate integration in such WSN nodes and, hence, potentially reduce size and costs.

The purpose of this paper is to design an on-chip inductor with high inductance, high-quality factor and high self-resonance frequency for the equivalent on-chip area using fractal curves.

A novel hybrid series stacked differential fractal inductor using Hilbert and Sierpinski fractal curves is proposed with two different layers connected in series using vias. The inductor is implemented in Sonnet EM simulator using 180 nm CMOS standard process technology.

The proposed inductor reduces the parasitic capacitance and negative mutual inductance between the adjacent layers with significant improvement in overall inductance, quality factor and self-resonance frequency when compared with conventional series stacked fractal inductors.

The fractal inductor is used to create high inductance in the single-layer process, but access to multilayers is restricted owing to unusual and expensive fabrication processes.

The proposed inductor can be used in implementation of low noise amplifier, voltage controlled oscillators and power amplifiers.

This paper introduces a combination of two fractal curves to implement a hybrid fractal inductor that enhances the performance of the inductor.

The purpose of this study is to develop a high-quality factor fractal inductor for wireless applications such as satellite, WLAN, Bluetooth, microwave, radar and cellular phone.

The Hilbert fractal curve is used in the implementation of the proposed inductor. In the proposed inductor, the metal width has split into multiple paths based on the skin depth of the metal. The simulations of the proposed inductor are performed in 180 nm CMOS technology using the Advanced Design System EM simulator.

The multipath technique reduces the skin effects and proximity effects, which, in turn, decreases the series resistance of the inductor and attains high-quality factor over conventional fractal inductor for the equal on-chip area.

The width of the path has chosen higher than the skin depth of the metal for a required operating frequency. Due to cost constraints, the manufacturing of the proposed fractal inductor is limited to a single layer.

The proposed inductor will be useful for the implementation of critical building blocks of radio frequency integrated circuits and monolithic microwave integrated circuits such as low-noise amplifiers, voltage-controlled oscillators, mixers, filters and power amplifiers.

This paper presents for the first time the use of a multipath technique for the fractal inductors to enhance the quality factor.

The prolonged training time of the neural network (NN) has sparked considerable debate regarding their application in the field of optimization. The purpose of this paper is to explore the beneficial assistance of NN-based alternative models in inductance design, with a particular focus on multi-objective optimization and uncertainty analysis processes.

Under Gaussian-distributed manufacturing errors, this study predicts error intervals for Pareto points and select robust solutions with minimal error margins. Furthermore, this study establishes correlations between manufacturing errors and inductance value discrepancies, offering a practical means of determining permissible manufacturing errors tailored to varying accuracy requirements.

The NN-assisted methods are demonstrated to offer a substantial time advantage in multi-objective optimization compared to conventional approaches, particularly in scenarios where the trained NN is repeatedly used. Also, NN models allow for extensive data-driven uncertainty quantification, which is challenging for traditional methods.

Three objectives including saturation current are considered in the multi-optimization, and the time advantages of the NN are thoroughly discussed by comparing scenarios involving single optimization, multiple optimizations, bi-objective optimization and tri-objective optimization. This study proposes direct error interval prediction on the Pareto front, using extensive data to predict the response of the Pareto front to random errors following a Gaussian distribution. This approach circumvents the compromises inherent in constrained robust optimization for inductance design and allows for a direct assessment of robustness that can be applied to account for manufacturing errors with complex distributions.

A vertically stacked, three layer hybrid Hilbert fractal geometry and serpentine radiator-based patch antenna is proposed and characterized for medical implant applications at the Industrial, Scientific and Medical band (2.4-2.48 GHz). Antenna parameters are optimised to achieve miniaturized, biocompatible and stable transmission characteristics. The paper aims to discuss these issues.

Human tissue effects on the antenna electrical characteristics were simulated with a three-layer (skin, fat and muscle) human tissue model with the dimensions of 180×70×60 mm3 (width×height×thickness mm3). Different stacked substrates are utilized for the satisfactory characteristics. Two identical radiating patches are printed on Roger 3,010 (ε _r=10.2) and Alumina (ε _r=9.4) substrate materials, respectively. In addition, various superstrate materials are considered and simulated to prevent short circuit the antenna while having a direct contact with the metallization, and achieve biocompatibility. Finally, superstrate material of Zirconia (ε _r=29) is used to achieve biocompatibility and long-life. A finite element method is used to simulate the proposed hybrid model with commercially available Ansoft HFSS software.

The antenna is miniaturized, having dimensions of 10×8.4×2 mm3 (width×height×thickness mm3). The resonance frequency of the antenna is 2.4 GHz with a bandwidth of 100 MHz at return loss (S11) of better than −10 dB characteristics. Overall, the proposed antenna have 50 Ω impedance matching, −21 dB far field antenna gain, single-plane omni-directional radiation pattern properties and incident power of 5.3 mW to adhere Specific Absorption Rate regulation limit.

Vertically stacked three layer hybrid design have miniaturized characteristics, wide bandwidth, biocompatible, and stable characteristics in three layer human tissue model make this antenna suitable for implant biomedical monitor systems. The advanced simulation analysis of the proposed design constitutes the main contribution of the paper.

The paper aims to develop a wireless addressing interface circuitry for solid propellant microthruster array applications.

The solid propellant microthruster is a relatively new class of micropropulsion system for microspacecraft. To produce a controlled vectored thrust, a microthruster array is needed. Realization of the addressing ability and wireless communication is the key to the development of the microthruster array. Therefore, a prototype wireless addressing circuitry was developed to realize the addressing of the microthruster array by a multiplexing system. The addressing circuitry also enables measurement of the igniter temperature variation with time by measuring the igniter resistance change and automatic control by RS232 and RF wireless communications. Operating principles, design, fabrication, and testing of the circuitry are addressed.

A prototype integrated wireless addressing circuitry was designed and fabricated to realize the addressing of individual microthrusters in the microthruster array, to measure the igniter temperature variation with time, and to achieve automatic control using RS232 and RF wireless communications. Using the programmable voltage source in the circuitry, the igniter temperature could be accurately controlled in 256 steps using an 8 bit word. The 10 bit analog‐to‐digital converter feedback loop circuitry enabled real‐time monitoring of each igniter in the microthruster array and allowing each igniter to be functionally controlled.

In this paper, a wireless addressing interface circuitry is developed for the first time for solid propellant microthruster array applications.