scholarly journals Effect of Fiber Weave Structure in Printed Circuit Boards on Signal Transmission Characteristics

2019 ◽  
Vol 9 (2) ◽  
pp. 353 ◽  
Author(s):  
Bei Chen ◽  
Ruohe Yao ◽  
Hongfei Wang ◽  
Kuiwei Geng ◽  
Juan Li

In this paper, we characterized and compared signal transmission performances of traces with different specifications of fiber weave. Measurements demonstrated that the dielectric constant, impedance fluctuation, and differential skew were all affected by fiber weave style. For flattened fiber weaves, the dielectric constant fluctuation reached 0.18, the impedance fluctuation amplitude was 1.0 Ω, and the differential skew was 2 ps/inch. For conventional fiber weaves, the three parameters were 0.44, 2.5 Ω, and 4 ps/inch respectively. Flattened fiber weave was more favorable for high-speed signal control. We also discussed the other methods to improve the fiber weave effect. It turned out that NE-glass (new electronic glass) fiber weave also had better performance in reducing impedance fluctuation and differential skew. Furthermore, made the signal traces and fiber weave bundles with an angle or designing the long signal line parallel to the weft direction both are simple and effective methods to solve this problem.

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 299 ◽  
Author(s):  
Myunghoi Kim

An analytical model for metamaterial differential transmission lines (MTM-DTLs) with a corrugated ground-plane electromagnetic bandgap (CGP-EBG) structure in high-speed printed circuit boards is proposed. The proposed model aims to efficiently and accurately predict the suppression of common-mode noise and differential signal transmission characteristics. Analytical expressions for the four-port impedance matrix of the CGP-EBG MTM-DTL are derived using coupled-line theory and a segmentation method. Converting the impedance matrix into mixed-mode scattering parameters enables obtaining common-mode noise suppression and differential signal transmission characteristics. The comprehensive evaluations of the CGP-EBG MTM-DTL using the proposed analytical model are also reported, which is validated by comparing mixed-mode scattering parameters Scc21 and Sdd21 with those obtained from full-wave simulations and measurements. The proposed analytical model provides a drastic reduction of computation time and accurate results compared to full-wave simulation.


2021 ◽  
pp. 004051752198978
Author(s):  
Huating Tu ◽  
Yaya Zhang ◽  
Hong Hong ◽  
Jiyong Hu ◽  
Xin Ding

Nowadays, the chipless radio frequency identification (RFID) tag is attracting significant attention owing to its immense potential in tracking. However, most of the chipless tags are fabricated on hard printed circuit boards, and the wearable fabric-based chipless tag is still in the research stage. In this paper, a symmetrical 3rd L-shaped multi-resonator wearable chipless RFID tag is designed and screen-printed onto fabric. In order to investigate the influence of the non-uniform conductive layer on the signal transmission at high frequency, the surface and cross-sectional topographies of the printed conductive film are analyzed and the frequency response characteristics are simulated and measured. The obtained results show that the common fabric can be used as the substrate to screen print the L-shaped multi-resonators of the chipless RFID tag, and the quality of the screen printed line, especially a narrow line, significantly affects the radio frequency performance. For the screen-printed 3rd L-shaped stub resonators, the relative frequency shift compared with the simulation results are 0.99%, 0.88% and 2.26%, respectively. Generally, the surface morphology of fabric and screen-printed precision are critical in improving the performance of L-shaped multi-resonators.


Author(s):  
S.V. Palochkin ◽  
Y.V. Sinitsyna ◽  
K.G. Erastova

The increased accuracy in high-speed positioning of the parallel robot effector in comparison with that of serial robots with a sequential structure is often the main reason for their use in various modern industries, such as the manufacture of printed circuit boards for microelectronics. However, despite the higher theoretical positioning accuracy, due to the kinematic structure of the parallel robot, in practice this characteristic largely depends on the accuracy of manufacturing individual elements of this mechanism, the most important of which are the gearboxes of the drives of its input pairs. A solution to the urgent problem of determining the effect of the manufacturing accuracy of planetary pinion gearboxes included in the drive of a five-link parallel robot on the positioning accuracy of its output link is proposed. A specific relationship has been determined between the grade of accuracy number of the gear part dimensions and the robot positioning accuracy. The unevenness of the positioning accuracy along the coordinate axes of its working area is revealed. It was found that near the area of certain robot positions the accuracy of its positioning drops sharply.


2018 ◽  
Vol 2018 (1) ◽  
pp. 000305-000309 ◽  
Author(s):  
Shiro Tatsumi ◽  
Shohei Fujishima ◽  
Hiroyuki Sakauchi

Abstract Build-up process is a highly effective method for miniaturization and high density integration of printed circuit boards. Along with increasing demands for high transmission speed of electronic devices with high functionality, packaging substrates installed with semiconductors in such devices are strongly required to reduce the transmission loss. Our insulation materials are used in a semi-additive process (SAP) with low dielectric loss tangent, smooth resin surface after desmear, and good insulation reliability. Actually, the transmission loss of strip line substrates and Cu surface roughness impact on transmission loss were measured using our materials. Furthermore, low dielectric molding film with low coefficient of thermal expansion (CTE) and low Young's modulus are introduced.


2013 ◽  
Vol 655-657 ◽  
pp. 88-93 ◽  
Author(s):  
Luciano Arruda ◽  
Cristiano Coimbra ◽  
João Marco Andolfatto

This work is related to reliability of strain measurement in flexible printed circuit boards (fPCBs) made with polyimide substrate. It was observed that the fPCBs are very sensitive to strain mounting stiffness. The indirect measurement method will be done employing High Speed Camera (HSP). The direct method will be formulated in two ways: 1) conventional strain gauge glued in an fPCBs; 2) printed strain gauge in a polyimide substrate. This paper will point out mistakes and show advantages when using different method to extract the deformation field of the selected area in a flexible thin film.


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