An integrated design system for molded interconnect devices (3D-MID)

In this paper, MIDCAD, an integrated design system for Molded Interconnect Devices, is presented and some important techniques for the development of this design system are discussed. A series of MID-related specialfunctions and an integrated MID product model, which are not supported by conventional MCAD unit ECAD systems, were developed in MIDCAD. Based on the product model, the simulation of the injection molding process is successfully integrated into MIDCAD. A module supporting the connection of MID-specific automatic placement equipment is also being developed in MIDCAD in order to he able to accomplish a manufacturing-oriented optimization and to guarantee the manufacturability of MID products

High-frequency characterization of embedded components in printed circuit boards

The embedding of electronic components is a three-dimensional packaging technology, where chips are placed inside of the printed circuit board instead of on top. The advantage of this technology is the reduced electronic interconnection length between components. The shorter this connection, the faster the signal transmission can occur. Different high-frequency aspects of chip embedding are investigated within this dissertation: interconnections to the embedded chip, crosstalk between signals on the chip and on the board, and interconnections running on top of or underneath embedded components. The high-frequency behavior of tracks running near embedded components is described using a broadband model for multilayer microstrip transmission lines. The proposed model can be used to predict the characteristic impedance and the loss of the lines. The model is based on two similar approximations that reduce the multilayer substrate to an equivalent single-layer structure. The per-unit-length shunt impedance parameters are derived from the complex effective dielectric constant, which is obtained using a variational method. A complex image approach results in the calculation of a frequency-dependent effective height that can be used to determine the per-unit-length resistance and inductance. A deliberate choice was made for a simple but accurate model that could easily be implemented in current high-frequency circuit simulators. Next to quasi-static electromagnetic simulations, a dedicated test vehicle that allows for the direct extraction of the propagation constant of these multilayer microstrips is manufactured and used to verify the model. The verification of the model using simulation and measurements shows that the proposed model slightly overestimates the loss of the measured multilayer microstrips, but is more accurate than the simulations in predicting the characteristic impedance

Ono: an open platform for social robotics

In recent times, the focal point of research in robotics has shifted from industrial ro- bots toward robots that interact with humans in an intuitive and safe manner. This evolution has resulted in the subfield of social robotics, which pertains to robots that function in a human environment and that can communicate with humans in an int- uitive way, e.g. with facial expressions. Social robots have the potential to impact many different aspects of our lives, but one particularly promising application is the use of robots in therapy, such as the treatment of children with autism. Unfortunately, many of the existing social robots are neither suited for practical use in therapy nor for large scale studies, mainly because they are expensive, one-of-a-kind robots that are hard to modify to suit a specific need. We created Ono, a social robotics platform, to tackle these issues. Ono is composed entirely from off-the-shelf components and cheap materials, and can be built at a local FabLab at the fraction of the cost of other robots. Ono is also entirely open source and the modular design further encourages modification and reuse of parts of the platform

A Digital Manufacturing Process For Three-Dimensional Electronics

Additive manufacturing (AM) offers the ability to produce devices with a degree of three-dimensional complexity and mass customisation previously unachievable with subtractive and formative approaches. These benefits have not transitioned into the production of commercial electronics that still rely on planar, template-driven manufacturing, which prevents them from being tailored to the end user or exploiting conformal circuitry for miniaturisation. Research into the AM fabrication of 3D electronics has been demonstrated; however, because of material restrictions, the durability and electrical conductivity of such devices was often limited. This thesis presents a novel manufacturing approach that hybridises the AM of polyetherimide (PEI) with chemical modification and selective light-based synthesis of silver nanoparticles to produce 3D electronic systems. The resulting nanoparticles act as a seed site for the electroless deposition of copper. The use of high-performance materials for both the conductive and dielectric elements created devices with the performance required for real-world applications. For printing PEI, a low-cost fused filament fabrication (FFF); also known as fused deposition modelling (FDM), printer with a unique inverted design was developed. The orientation of the printer traps hot air within a heated build environment that is open on its underside allowing the print head to deposit the polymer while keeping the sensitive components outside. The maximum achievable temperature was 120 °C and was found to reduce the degree of warping and the ultimate tensile strength of printed parts. The dimensional accuracy was, on average, within 0.05 mm of a benchmark printer and fine control over the layer thickness led to the discovery of flexible substrates that can be directly integrated into rigid parts. Chemical modification of the printed PEI was used to embed ionic silver into the polymer chain, sensitising it to patterning with a 405 nm laser. The rig used for patterning was a re-purposed vat-photopolymerisation printer that uses a galvanometer to guide the beam that is focused to a spot size of 155 µm at the focal plane. The positioning of the laser spot was controlled with an open-sourced version of the printers slicing software. The optimal laser patterning parameters were experimentally validated and a link between area-related energy density and the quality of the copper deposition was found. In tests where samples were exposed to more than 2.55 J/cm^2, degradation of the polymer was experienced which produced blistering and delamination of the copper. Less than 2.34 J/cm^2 also had negative effect and resulted in incomplete coverage of the patterned area. The minimum feature resolution produced by the patterning setup was 301 µm; however, tests with a photomask demonstrated features an order of magnitude smaller. The non-contact approach was also used to produce conformal patterns over sloped and curved surfaces. Characterisation of the copper deposits found an average thickness of 559 nm and a conductivity of 3.81 × 107 S/m. Tape peel and bend fatigue testing showed that the copper was ductile and adhered well to the PEI, with flexible electronic samples demonstrating over 50,000 cycles at a minimum bend radius of 6.59 mm without failure. Additionally, the PEI and copper combination was shown to survive a solder reflow with peak temperatures of 249°C. Using a robotic pick and place system a test board was automatically populated with surface mount components as small as 0201 resistors which were affixed using high-temperature, Type-V Tin-Silver-Copper solder paste. Finally, to prove the process a range of functional demonstrators were built and evaluated. These included a functional timer circuit, inductive wireless power coils compatible with two existing standards, a cylindrical RF antenna capable of operating at several frequencies below 10 GHz, flexible positional sensors, and multi-mode shape memory alloy actuators

3D manufacturing using laser direct structuring and the application on the development of antenna systems

The development of radio systems is subject to constantly increasing demands. These concern the function to be implemented as well as the geometric dimensions of the RF devices in decreasing installation spaces. One resulting aspect is that the antenna can no longer be developed as a single component and be integrated subsequently. It is rather necessary to consider the installation space as a part of the antenna and to use it electromagnetically according to the requirements. One manufacturing technology that inherently takes up this approach is Moulded Interconnect Devices (MID) technology. MIDs are three-dimensional plastic parts which are selectively metallised. The electronic/electromagnetic functionalisation of mechanical components, such as housing parts, is thus possible. The manufacturing and material parameters of the different MID manufacturing processes are often characterised regarding the mechanical or electrical requirements, although e.g. the MID LDS (Laser Direct Structuring) process has been used for years for the production of antennas in consumer devices. Therefore, the main aim of the present work is to carry out a structured technological analysis of the LDS process for high-frequency applications up to 70 GHz and to verify the results by means of antenna developments, which use the three-dimensional design scope provided by the technology. After a description of the manufacturing process of the LDS process, the relevant parameters with regard to radio frequency systems are derived. Based thereon, a detailed discussion of the mechanical parameters, the dielectric material parameters of the LDS plastics as well as the applied metallisation is carried out. The results are verified by measurements. These findings are subsequently used in the development of various antenna concepts which can be fabricated using the LDS process. First of all, two antenna systems are developed to be integrated into a vehicle. The first system takes up a current installation space, a roof antenna module, while a second system is aimed at a new installation space. The developed antennas are realised with the LDS method and subsequently characterised. In addition, two antenna concepts are examined which are independent of a specific installation space, but which take into account the possibility of adapting them to the installation space as an optimisation goal. One concept covers the use of 3D manufacturing in connection with microstrip antennas. A prototype of an active patch antenna for Global Positioning Satellite System (GPS) which combines circuit and antenna on a three-dimensional substrate is realised. The second approach includes antennas which are fed by dielectric filled waveguides. Two prototypes in the 24 GHz and 61 GHz ISM band verify the suitability of the manufacturing technology for frequencies in the millimetre wavelength range. Finally, the antenna concept is investigated on the basis of electromagnetic field simulations in a generic installation space

Large-area flexible printed circuits for automotive applications

To meet the demands for safety and passenger comfort, modem passenger cars offer more and increasingly sophisticated electrical and electronic systems. The wiring harnesses that support such systems become too large, complex and heavy, when designed for a conventional electrical architecture based on 14 volts, posing several challenges to automotive manufacturers. Alternative electrical architectures based on 42 volts and in-vehicle multiplexing promise to reduce the size and weight of the wiring harness, but these architectures are yet to be fully developed and standardized. In the near term, alternative wiring solutions have gained the interest of automotive manufacturers. Small flexible printed circuits (FPCs) have previously been integrated into automotive instrument clusters. The benefits of reduced weight and space requirements of such FPCs compared to a wire harness has fuelled an interest in much larger FPCs as substitutes for the Instrument Panel and door harnesses in high-volume production cars. This research investigates the materials typically used in FPC manufacture, for applicability within a passenger car. [Continues.

Pluggable Optical Connector Interfaces for Electro-Optical Circuit Boards

A study is hereby presented on system embedded photonic interconnect technologies, which would address the communications bottleneck in modern exascale data centre systems driven by exponentially rising consumption of digital information and the associated complexity of intra-data centre network management along with dwindling data storage capacities. It is proposed that this bottleneck be addressed by adopting within the system electro-optical printed circuit boards (OPCBs), on which conventional electrical layers provide power distribution and static or low speed signaling, but high speed signals are conveyed by optical channels on separate embedded optical layers. One crucial prerequisite towards adopting OPCBs in modern data storage and switch systems is a reliable method of optically connecting peripheral cards and devices within the system to an OPCB backplane or motherboard in a pluggable manner. However the large mechanical misalignment tolerances between connecting cards and devices inherent to such systems are contrasted by the small sizes of optical waveguides required to support optical communication at the speeds defined by prevailing communication protocols. An innovative approach is therefore required to decouple the contrasting mechanical tolerances in the electrical and optical domains in the system in order to enable reliable pluggable optical connectivity. This thesis presents the design, development and characterisation of a suite of new optical waveguide connector interface solutions for electro-optical printed circuit boards (OPCBs) based on embedded planar polymer waveguides and planar glass waveguides. The technologies described include waveguide receptacles allowing parallel fibre connectors to be connected directly to OPCB embedded planar waveguides and board-to-board connectors with embedded parallel optical transceivers allowing daughtercards to be orthogonally connected to an OPCB backplane. For OPCBs based on embedded planar polymer waveguides and embedded planar glass waveguides, a complete demonstration platform was designed and developed to evaluate the connector interfaces and the associated embedded optical interconnect. Furthermore a large portfolio of intellectual property comprising 19 patents and patent applications was generated during the course of this study, spanning the field of OPCBs, optical waveguides, optical connectors, optical assembly and system embedded optical interconnects

ReSCon '09, Research Student Conference: Book of Abstracts

The second SED Research Student Conference (ReSCon2009) was hosted over three days, 22-24 June 2009, in the Lecture Centre at Brunel University. The conference consisted of technical presentations, a poster session and social events. The abstracts and presentations were the result of ongoing research by postgraduate research students from the School of Engineering and Design at Brunel University. The conference is held annually, and ReSCon plays a key role in contributing to research and innovations within the School