Improving the Signal Integrity, Impedance Control and Attenuation of the Thin Transmission Lines Printed on Flexible Substrates

Author(s):  
Zhenhao Liang ◽  
Yanpeng Xie ◽  
Qiang Chen
2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000968-000985
Author(s):  
Pingye Xu ◽  
Michael C. Hamilton

This work explores a method to construct metal-coated carbon nanotube (CNT) structures, which are potential candidates for interconnects, transmission lines and contact structures. This simple method is suitable to many applications including flexible substrates. In this work, electroplating is used to coat a carbon nanotube surface with Indium. CNT films are prepared using drop casting method on different substrates: Ni coated silicon wafer, copy paper and photo paper. The CNT dispersion used for this work is prepared using sonication and centrifugation with a surfactant. The resulting dispersion has 0.8 wt. % of multi-walled CNTs and 0.5 wt. % of sodium dodecyl sulfate (SDS) in DI water. This dispersion is modified to reduce resistivity by adding either silver nanoparticle powder or silver ink. Electroplating is done at room temperature with a current density of 0.02 A/cm2. This work addresses two issues about electroplating on CNT: low electrical conductivity of CNT film and low CNT adhesion to substrate. A CNT film on a Ni surface displays poor adhesion; the film peels off easily during ultrasonication and electroplating. After thermal annealing or microwave treatment, adhesion between the CNT film and Ni is greatly enhanced such that no CNT film peel-off is observed during electroplating. A CNT film on paper has a high sheet resistance. As a result, Indium is only plated on the CNT film near the attached electrode. To reduce the film sheet resistance, the CNT solution is modified by adding silver nanoparticle powder or silver ink. Ethanol rinsing is also performed on the CNT film surface to wash away surfactant and further reduce sheet resistance. On-going work involves ink-jet printing of CNT solutions onto flexible substrates. Indium, as an example metallization, will be plated on these ink-jet printing defined transmission lines and interconnects patterns. Performance of these structures will be presented.


2013 ◽  
Vol 760-762 ◽  
pp. 320-324
Author(s):  
Shi Lei Zhou ◽  
Ya Lin Guan ◽  
Xin Kun Tang

High-speed signal connector has become a key factor of the signal transmission quality in telecommunications and data communications system. Signal integrity of connector is an inevitable problem. This paper based on the theory of differential transmission lines and Multimode S-Parameters, analyzed the USB3.0 connector signal integrity. And use 3D simulation software CST to build model and analyze the relationship of signal integrity and connectors geometry.


2021 ◽  
Vol 21 (1) ◽  
pp. 44-50
Author(s):  
Young-Chul Yoon ◽  
Young Kim

This study proposes an impedance control method in transmission lines using open- or short-circuit stubs for unequal power dividers. The proposed method is based on the conversion of a two-port to a three-port transmission line, which is equivalent to multiplying the impedance at the internal transmission line by a scaling factor and then connecting open- or short-circuit stubs in parallel to each port on the three-port transmission line. To verify the effectiveness of the proposed method, Wilkinson and Gysel power dividers with splitting ratios of 9:1 and 5:1, respectively, using uniform impedance transmission lines with open- or short-circuit stubs at an operating frequency of 2 GHz were designed. The experimental measurements of the two power dividers agree well with those of the simulation.


2013 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
T. Eudes ◽  
B. Ravelo ◽  
R. Al-Hayek

This paper presents an enlarged study about the 50-% propagation-time assessment of cascaded transmission lines (TLs). First and foremost, the accurate modeling and measurement technique of signal integrity (SI) for high-rate microelectronic interconnection is recalled. This model is based on the reduced transfer function extracted from the electromagnetic (EM) behavior of the interconnect line RLCG-parameters. So, the transfer function established takes into account both the frequency dispersion effects and the different propagation modes. In addition, the transfer function includes also the load and source impedance effects. Then, the SI analysis is proposed for high-speed digital signals through the developed model. To validate the model understudy, a prototype of microstrip interconnection with w = 500 µm and length d = 33 mm was designed, simulated, fabricated and tested. Then, comparisons between the frequency and time domain results from the model and from measurements are performed. As expected, good agreement between the S-parameters form measurements and the model proposed is obtained from DC to 8 GHz. Furthermore, a de-embedding method enabling to cancel out the connectors and the probe effects are also presented. In addition, an innovative time-domain characterization is proposed in order to validate the concept with a 2.38 Gbit/s-input data signal. Afterwards, the 50-% propagation-time assessment problem is clearly exposed. Consequently an extracting theory of this propagation-time with first order RC-circuits is presented. Finally, to show the relevance of this calculation, propagation-time simulations and an application to signal integrity issues are offered.


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