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The purpose of this paper is to develop a highly miniaturized wireless inertial sensor system based on a novel 3D packaging technique using a flexible printed circuit (FPC). The device is very suitable for wearable applications in which small size and lightweight are required such as body area network, medical, sports and entertainment applications.

Modern wireless inertial measurement units are typically implemented on a rigid 2D printed circuit board (PCB). The design concept presented here is based around the use of a novel planar, six‐faceted, crucifix or cross‐shaped FPC instead of a rigid PCB. A number of specific functional blocks (such as microelectromechanical systems gyroscope and accelerometer sensors, microcontroller (MCU), radio transceiver, antenna, etc.) are first assigned to each of the six faces which are each 1 cm² in area. The FPC cross is then developed into a 1 cm³, 3D configuration by folding the cross at each of five bend planes. The result is a low‐volume and lightweight, 1 cm³ wireless inertial sensor that can sense and send motion sensed data wirelessly to a base station. The wireless sensor device has been designed for low power operation both at the hardware and software levels. At the base station side, a radio receiver is connected to another MCU unit, which sends received data to a personal computer (PC) and graphical user interface. The industrial, scientific and medical band (2.45 GHz) is used to achieve half duplex communication between the two sides.

A complete wireless sensor system has been realized in a 3D cube form factor using an FPC. The packaging technique employed during the work is shown to be efficient in fabricating the final cubic system and resulted in a significant saving in the final size and weight of the system. A number of design issues are identified regarding the use of FPC for implementing the 3D structure and the chosen solutions are shown to be successful in dealing with these issues.

Currently, a limitation of the system is the need for an external battery to power the sensor system. A second phase of development would be required to investigate the possibility of the integration of a battery and charging system within the cube structure. In addition, the use of flexible substrate imposes a number of restrictions in terms of the ease of manufacturability of the final system due to the requirement of the required folding step.

The small size and weight of the developed system is found to be extremely useful in different deployments. It would be useful to further explore the system performance in different application scenarios such as wearable motion tracking applications. In terms of manufacturability, component placement needs to be carefully considered, ensuring that there is sufficient distance between the components, bend planes and board edges and this leads to a slightly reduced usable area on the printed circuit.

This paper provides a novel and useful method for realizing a wireless inertial sensor system in a 3D package. The value of the chosen approach is that a significant reduction in the required system volume is achieved. In particular, a 78.5 per cent saving in volume is obtained in decreasing the module size from a 25 to a 15 mm³ size.

This paper aims to describe the simulation, design, development and characterisation of antennas for wireless sensor networks operating in a variety of environments, including an under water submarine application and more usual “open air” deployments.

The experimental test methodology, fixtures, conditions and results used to characterize the performance of these antennas (both state of the art commercially available and those developed in‐house) are presented.

The underwater test results show a near omni‐directional pattern about the three principal axes, thus showing that a spherical field has been achieved for localisation purposes (with a certain loss of resolution).

The paper focuses on the development of a new antenna scheme to enable under water communications between robotic agents.

Multilayer aircore inductors fabricated in a range of interconnection technologies which are MCM compatible are presented and compared. These consist of thick‐film, low temperature cofired ceramic (LTCC), printed circuit board (PCB) and fine‐line plated copper on ceramic (copper plating). From a comparison of simulated and measured results, it can be concluded that a predictive design capability has been achieved for inductance and self‐resonant frequency (SRF). Modelling of AC resistance and Q requires further investigation.

This paper will focus on the work which was carried out under the Brite‐EuRAM funded project, COMPRISE (BE 96‐3371), the objective of which was to develop new materials and manufacturing processes to embed passive components (resistors, inductors, capacitors) within printed wiring structures fabricated from laminate materials. For the realisation of integrated resistors, a commercially available planar resistor material is incorporated in different test structures. The technology consists of a copper foil of standard thickness on which a resistive layer is deposited by means of electroless plating. For the realisation of capacitors in multi‐layered PCB structures, significant progress was made in the development and fabrication of very thin laminates. Higher dielectric constants of these laminate materials enable the increase of the capacitance per unit area. For inductors, both aircore (no magnetic material) and magnetic core components have been investigated.

This paper's purpose is to review the design of a flip chip thermal test vehicle.

Design requirements for different applications such as thermal characterization, assembly process optimization, and product burn‐in simulation are outlined and the design processes of different thermal test chip structures including the temperature sensor and passive heaters are described in detail. The design of fireball heater, a novel test chip structure used for evaluating the effectiveness of heat spreading of advanced thermal solutions, is also explained.

Describes the design considerations and processes of the package substrate and printed‐circuit board with special emphasis on the physical routing of the thermal test chip structures. These design processes are supported with thermal data from various finite‐element analyses carried out to evaluate the capability and limitations of thermal test vehicle design.

The validation and calibration procedures of a thermal test vehicle are presented in this paper.

As the hybrid market changes, many hybrid companies are being forced to adjust to reduced defence budgets and to the encroachment of epoxy board based SMT on traditional hybrid areas. This paper considers the establishment of an intelligent power module technology as a viable way to utilise the strengths of hybrid technology, in a field where there is an expanding market and, at present, not too much competition. The basic techniques are described, some of the potential pitfalls are highlighted, and the likely scale of technical and personnel investment is indicated.

The purpose of this paper is to present the stages for manufacturing a low‐cost miniaturized prototype device, which observes the restrictions of implantable medical devices. The device measures the electrocardiography. The power for the implant is received passively as the same magnetic field as data is transferred to the reader device.

In this manufacturing technique, only easily attachable commercial available components are used, etching is used to simply produce a low‐cost double‐sided flexible printed circuit board which is converted to 3D by folding.

The circuit board was folded into the final shape after component attachment and the final result was a compact 3D package within the specifications determined by the electronics designer. The miniaturized prototype device was successfully tested both in vitro and in vivo.

The manufacturing technique of the sensing device can be readily adapted to other devices that need to be miniaturized. The coatings used for electrical insulation and chemical protection and the type of adhesives used for folded packages are easily utilized in similar miniaturization prototypes. By using bare chips, the final product would have been even smaller but for prototyping it is cheaper and faster to use easily acquired and attached components. In the case of mass production, the whole new design, where bare chips with flip chip attachments, integrated passives and/or stacked 3D packages with design considerations such as electrical, thermal and mechanical engineering is justified.

A decade and a half after the debut of pervasive computing, a large number of prototypes, applications, and interaction interfaces have emerged. However, there is a lack of consensus about the best approaches to create such systems or how to evaluate them. To address these issues, this paper aims to develop a performance evaluation framework for pervasive computing systems.

Based on the authors' experience in the Gator Tech Smart House – an assistive environment for the elderly, they established a reference scenario that was used to guide the analysis of the large number of systems they studied. An extensive survey of the literature was conducted, and through a thorough analysis, the authors derived and arrived at a broad taxonomy that could form a basic framework for evaluating existing and future pervasive computing systems.

A taxonomy of pervasive systems is instrumental to their successful evaluation and assessment. The process of creating such taxonomy is cumbersome, and as pervasive systems evolve with new technological advances, such taxonomy is bound to change by way of refinement or extension. This paper found that a taxonomy for something so broad as pervasive systems is very complex. It overcomes the complexity by focusing the classifications on key aspects of pervasive systems, decided purely empirically and based on the authors own experience in a real‐life, large‐scale pervasive system project.

There are currently no methods or frameworks for comparing, classifying, or evaluating pervasive systems. The paper establishes a taxonomy – a first step toward a larger evaluation methodology. It also provides a wealth of information, derived from a survey of a broad collection of pervasive systems.

The purpose of this paper is to investigate the basic functional parameters of passive embedded components in printed circuit boards (PCBs) under environmental exposures such as thermal-humidity and thermal exposure.

The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon–silver inks, embedded capacitors made of FaradFlex materials and embedded inductor made in various configurations. The capacitors and thin- and thick-film resistors were tested in the climatic chamber in conditions of thermal-humidity exposure at 85°C and 85 per cent RH for 500 h. The embedded inductors were tested in two different environmental conditions: thermal-humidity exposure at 60°C and 95 per cent RH, and thermal exposure at 150°C and additionally at the temperature in the range of +25°C to +150°C.

Studies show that in the case of embedded capacitors, the changes caused by exposure to thermal-humidity are durable and lead to the capacity increase. The embedded thin-film resistors behave in the same manner, whereas the thick-film resistors were the least resistant to the conditions of exposure. Most of the polymer thick-film resistors have been damaged. The changes of coils' properties during aging are small, and what is most important is that, after some time of exposure, their parameters stabilize at a particular level. The changes resulting from the increase in temperature are typically related to the change of material resistance (Cu) of which coils are made, and as such, they cannot be avoided but they can be predicted.

The realized studies allowed determination of the properties of the embedded passive elements with respect to specific environmental exposures. The studies show that embedded resistors can be used interchangeably with chip passive elements. It allows saving the area on the surface of PCB, occupied by these passive elements, for assembly of active elements integrated circuits (ICs) and thus enabling the miniaturization of electronic devices.

The knowledge about the behavior of the operating parameters of embedded components, considering the environmental conditions, allows for development of more complex systems with integrated PCBs.

This paper aims to investigate the mechanism of Ni particles distribution in the liquid Sn3.5Ag melt under the external static magnetic field. The control steps of Ni particles and the Sn3.5Ag melt metallurgical process were studied. After aging, the microhardness of pure Sn3.5Ag, Sn3.5Ag containing randomly distributed Ni particles and Sn3.5Ag containing columnar Ni particles were compared.

Place the sample in a crucible for heating. After the sample melts, place a magnet directly above and below the sample to provide a magnetic field. Sn3.5Ag with the different morphological distribution of Ni particles was obtained by holding for different times under different magnetic field intensities. Finally, pure Sn3.5Ag, Sn3.5Ag with random distributed Ni particles and Sn3.5Ag with columnar Ni particles were aged and their microhardness was tested after aging.

The experimental results show that with the increase of magnetic field strength, the time for Ni particle distribution in Sn3.5Ag melt to reach equilibrium is shortened. After aging, the microhardness of Sn3.5Ag containing columnar nickel particles is higher than that of pure Sn3.5Ag and Sn3.5Ag containing randomly distributed nickel particles. A chemical reaction is the control step in the metallurgical process of nickel particles and molten Sn3.5Ag.

Under the action of the magnetic field, Ni particles in Sn3.5Ag melt will be arranged into columns. With the increase of magnetic field strength, the shorter the time for Ni particles in Sn3.5Ag melt to arrange in a column. With the extension of the service time of the solder joint, if Sn3.5Ag with columnar nickel particles is used as the solder joint material, its microhardness is better than Sn3.5Ag with arbitrarily distributed nickel particles and pure Sn3.5Ag.