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Author

R. Legtenberg

Bio: R. Legtenberg is an academic researcher from Thales (Netherlands). The author has contributed to research in topics: Conceptual design & Printed circuit board. The author has an hindex of 3, co-authored 5 publications receiving 25 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the contribution of various copper features on constituent layers of a printed circuit board (PCB) to the board's macroscopic multilayer properties in terms of stiffness and coefficient of thermal expansion (CTE) has been determined.
Abstract: Due to the ongoing component miniaturization and integration in the electronics industry, there is a need for asymmetric lay-ups for printed circuit boards (PCBs), especially in the case of complex boards that house both analog and digital circuits. This paper focuses on the contribution of the constituent layers that make up the PCB to the board’s macroscopic multilayer properties in terms of stiffness and coefficient of thermal expansion (CTE). The thermoelastic material properties for constituents, like cured prepreg and laminate layers, have been determined. Using classical laminate theory, individual layer properties are assembled to the macroscopic level and compared to fabricated multilayer boards. Following this approach, the contribution of various copper features on constituent layers can de deduced. The experiments show that properties of cured prepreg, taking z-direction expansion into account, and laminate layers are dependent on the type of fiberglass reinforcement and the fiber volume fraction. Depending on these properties, the Young’s modulus and CTE varies from 11 to 31 GPa and from 10 to 28 ppm/K, respectively. Datasheet values deviate significantly from these results as they do not take the fiber volume fraction into account. By alternating the measurement directions, the experiments have also shown that the fiberglass reinforcement plays a dominant role in determining macroscopic multilayer board properties. The multilayer board follows iso-strain conditions. Therefore, the material properties depend linearly on the copper volume fraction and follow the rule of mixtures independent of the type of copper patterning. Overall, the presented model and method to determine material properties increase the accuracy for predicting multilayer board behavior and offers the possibility to design and predict bow and twist behavior of PCBs with asymmetric lay-ups.

16 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the development of a novel cooling strategy for electronic packages, which increases design flexibility and results in electronic products with advantages in terms of performance, compactness, weight and production efficiency.
Abstract: This publication describes the development of a novel cooling strategy for electronic packages. During the conceptual design phase, the engineering disciplines involved are considered simultaneously. Through a case study, it is demonstrated that this integrative approach is an effective methodology leading to an innovative design. A novel, improved and highly integrated cooling strategy for electronic packages is presented. Standardized package types, as for instance ball grid array packages, are equipped with a directly injected cooling support. The developed concept is a new and very cost effective concept, as fewer productions steps and fewer procured parts are required compared to traditional cooling concepts. The new concept is also easily scalable, as multiple components on an electronic product can be cooled both uniformly across the product and simultaneously. This increases design flexibility and results in electronic products with advantages in terms of performance, compactness, weight and production efficiency.

11 citations

Journal ArticleDOI
TL;DR: In this paper, an analytical method to predict deformations of printed circuit boards (PCBs) in relation to their manufacturing process steps is presented, which includes the results of subsequent production steps, such as bonding, multilayer press cycles and patterning processes.

8 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a dual-polarized magneto-electric (ME) dipole antenna is implemented in the printed ridge gap waveguide (PRGW) technology, which achieves a 23.4% relative impedance bandwidth at 30 GHz with isolation better than 20 dB over the whole operating frequency band.
Abstract: In this communication, a dual-polarized magneto-electric (ME) dipole antenna is implemented in the printed ridge gap waveguide (PRGW) technology. The antenna is composed of a cross-shaped ME-dipole backed by an artificial magnetic conductor (AMC) sidewall cavity. This cavity is fed by two orthogonal PRGWs implemented in two separate layers to achieve a dual-polarization with −28 dB isolation level at the center operating frequency (30 GHz). The proposed antenna achieves a 23.4% relative impedance bandwidth at 30 GHz with isolation better than 20 dB over the whole operating frequency band. In addition, a gain enhancement technique is used to increase the gain to 10 dB over the operating bandwidth. A prototype is fabricated and there is a good agreement between simulated and measured results.

24 citations

Journal ArticleDOI
TL;DR: In this paper, a numerical investigation on the flow and heat transfer in a mini-channel where both hot liquid water and mercury co-flow together in a direct contact manner is presented.

16 citations

Journal ArticleDOI
TL;DR: In this paper, the contribution of various copper features on constituent layers of a printed circuit board (PCB) to the board's macroscopic multilayer properties in terms of stiffness and coefficient of thermal expansion (CTE) has been determined.
Abstract: Due to the ongoing component miniaturization and integration in the electronics industry, there is a need for asymmetric lay-ups for printed circuit boards (PCBs), especially in the case of complex boards that house both analog and digital circuits. This paper focuses on the contribution of the constituent layers that make up the PCB to the board’s macroscopic multilayer properties in terms of stiffness and coefficient of thermal expansion (CTE). The thermoelastic material properties for constituents, like cured prepreg and laminate layers, have been determined. Using classical laminate theory, individual layer properties are assembled to the macroscopic level and compared to fabricated multilayer boards. Following this approach, the contribution of various copper features on constituent layers can de deduced. The experiments show that properties of cured prepreg, taking z-direction expansion into account, and laminate layers are dependent on the type of fiberglass reinforcement and the fiber volume fraction. Depending on these properties, the Young’s modulus and CTE varies from 11 to 31 GPa and from 10 to 28 ppm/K, respectively. Datasheet values deviate significantly from these results as they do not take the fiber volume fraction into account. By alternating the measurement directions, the experiments have also shown that the fiberglass reinforcement plays a dominant role in determining macroscopic multilayer board properties. The multilayer board follows iso-strain conditions. Therefore, the material properties depend linearly on the copper volume fraction and follow the rule of mixtures independent of the type of copper patterning. Overall, the presented model and method to determine material properties increase the accuracy for predicting multilayer board behavior and offers the possibility to design and predict bow and twist behavior of PCBs with asymmetric lay-ups.

16 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the effect of gallium and mercury on heat removal from hot water co-flowing in a mini-channel in a direct contact manner with two liquid metals.
Abstract: Enhancement in the heat removal from hot water co-flowing in a mini-channel in a direct contact manner with two liquid metals, gallium and mercury, is investigated numerically. Results show that the liquid metals lead to superior heat removal from hot water co-flowing in the channel as compared to the case when only water flows in the channel. Moreover, it is found that gallium yields higher heat removal from water than mercury by about 15 %. This percentage, representing the superiority of gallium over mercury increases to about 20 % under conditions when the mass flow rate of both the liquid metal and the co-flowing water are doubled. The results reported showed numerical mesh independence. However, the results show much dependence on the spatial discretization scheme adopted where it is found that first order upwind scheme yields somewhat over predicted heat exchange rates in the channel, as compared with the case when a second order scheme is used. It is found further that the channel efficiency in removing heat from the water is remarkable in the first half of the overall channel length where in general the heat removed in the first 10 mm of the channel length is found to be about 70 % of the total heat removed. This percentage is a bit less than that when only water flows in the channel.

14 citations

Journal ArticleDOI
TL;DR: In this paper , the authors proposed a solution of structures built from stacking several dielectric substrates with the conducting cladding, aiming for electrical contact between them [perfect electric conductor (PEC)-PEC].
Abstract: This work proposed a solution of structures built from stacking several dielectric substrates with the conducting cladding, aiming for electrical contact between them [perfect electric conductor (PEC)–PEC]. At mm-wave frequencies, surface roughness or imperfect flat surfaces present possible gaps that cause severe unexpected leakage. Many engineers overlooked this problem. To prevent this leakage, we propose transforming one of the PEC–PEC surfaces into artificial magnetic conductors (AMCs), creating a PEC–AMC layer that suppresses any leakage even with no contact between the surfaces where the gap is less than a quarter wavelength. A wideband multilayer pyramidal horn antenna using substrate-integrated gap waveguide (SIGW) technology is proposed as an example that highlights the proposed solution. In each layer of the horn, the opening is surrounded by periodic cells to suppress leakage and surface waves. In addition, the upper surface surrounding the horn’s opening is surrounded by EBG mushroom cells to act as a soft surface that suppresses the surface waves and reduces the edge diffraction, and, in turn, improves the radiation characteristics of the horn. The horn achieved a gain of 11.5 dBi and 20.5% bandwidth (28.5–35 GHz). The simulated and measured results show excellent agreement with each other.

11 citations