Search

The work reports on the design and performance of a low-noise low-cost CMOS transimpedance amplifier (TIA). The proposed circuit shall be employed in optical time-domain reflectometers and is implemented using an affordable 0.18 µm 1.8 V CMOS process. The approach preserves the benefits of a classical feedback structure while addressing the noise problem of conventional feed-forward and resistive feedback architectures via the usage of noise-efficient capacitive feedback. Circuit-level modifications are proposed to mitigate the voltage headroom and DC current issues. The suggested design achieves a total gain of 82 dBΩ (79 dBΩ after the output buffer) within the bandwidth of 1.2 GHz while operating with a total input capacitance of 0.7 pF. The simulated average input-referred noise current density is below 1.8 pA/sqrt(Hz) with the power consumption of the complete amplifier including the output buffer being 21 mW.

This research review article provides a detailed examination of SMA (SubMiniature version A) connectors, which are integral components in high-frequency electronic systems. Through extensive S-parameter and time-domain reflectometry (TDR) measurements conducted on various SMA connector constructions, this study aims to evaluate the performance and impact of SMA connectors on signal integrity. Results reveal insights into the comparative performance of different SMA connector types mounted on PCB land pads, highlighting their strengths and limitations. Additionally, this paper explores the application of reference plane cut-outs for discontinuity impedance compensation, aiming to enhance the frequency response of SMA connectors. By linking measured performance parameters with relative market prices, this study offers valuable insights into the economic viability of different SMA connector types. The best and worst performing SMA connector measurements reveal an S11 < −10 dB bandwidth of more than 8 GHz and 1.5 GHz and a transition impedance of 46.5 Ω and 21 Ω, respectively. Overall, this research contributes to advancing the understanding and selection of SMA connectors for RF applications in telecommunications, aerospace, medical devices, and beyond. [ABSTRACT FROM AUTHOR]

The escalating component density in radio frequency (RF) systems presents a growing challenge related to the coupling of adjacent microstrip lines in high-density printed circuit boards (PCBs). As a result, to tackle this prominent issue, there is a continuous pursuit of innovative techniques to effectively minimize the coupling effects among closely spaced microstrip lines. This paper proposes a reduction in the coupling of adjacent lines by utilizing a coating (stiffener) layer, which is commonly used in rigid-flex PCB fabrication. For this purpose, a reference 50 Ohm coupled line performance was compared to three coupled lines with track widths of 1.39 mm, 1.30 mm, and 1.25 mm, respectively, all at a fixed distance between the tracks. These decreasing widths were used to achieve the same 50 Ohm impedance for the coupled lines when covered with different coating layers. Each of these three coupled lines was covered with different coating (stiffener) layers, measuring 0.1 mm, 0.3 mm, and 0.5 mm in thickness, respectively. The manufactured device under test (DUT) structures underwent time-domain reflectometry (TDR) and S-parameter measurements. The TDR measurements of the DUT structures with coating layers demonstrated excellent conformity to the 50 Ohm reference coupled line. Meanwhile, the S21 measurements indicated a significant decrease in the crosstalk. For example, for a coating layer thickness of 0.3 mm, the crosstalk decreased by approximately 5–6 dB within the frequency range up to 5 GHz. When the coating layer thickness was 0.5 mm, the crosstalk decreased by approximately 10 dB or more. [ABSTRACT FROM AUTHOR]

This article presents and describes in detail an interactive method of teaching and gathering feedback from students by applying internet‐based survey systems and utilizing smart devices. Real‐time survey results are monitored and analyzed by university staff and the lecturers, and these results are visible to other students as well. The presented method is probably the fastest and easiest way to receive feedback from students while increasing their interest and participation in lectures and laboratory work. The proposed method combines multiple means of gathering feedback from students, which include surveys, consultations, and group discussions. This interactive method has been applied for 5 years at the Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania. After analyzing 10 years of available statistical data, which included 5 years when the presented interactive survey method was applied, a 4–6% increase in student performance was observed. Therefore, we conclude that this is perhaps a direct consequence of applying the discussed interactive method. In addition, after analyzing student surveys, it has been observed that 86.37% of students evaluated the use of smart devices positively in conjunction with this teaching method process. The students also positively evaluated the teaching process overall, and highly encouraging responses were received to questions asking to rate class activities and class atmosphere using this interactive survey method—87.79% and 91.68%, respectively. A large number of positive responses reflect a positive student attitude towards the use of such interactive surveys in the study process and supports their benefits aimed at increasing the overall quality of education. [ABSTRACT FROM AUTHOR]

This article discusses one exemplary and one original laboratory work from the micro- and nano-electronics manufacturing process laboratory works cycle. These laboratory works have been successfully introduced into the undergraduate programme and have been attended by students for several years at Vilnius Gediminas Technical University, Faculty of Electronics. This laboratory work is unique in that it consistently displays and graphically depicts practically all CMOS transistor manufacturing processes: from the preparation of the silicon wafer to the final passivation. Silvaco TCAD tools are used in order to simulate these technological processes. This type of laboratory works provides students with the necessary knowledge of chip manufacturing processes and TCAD tools without the use of costly manufacturing equipment specific to each technological process in the fabrication chain, long-term experiments and a large amount of human resources. This article also presents and discusses student feedback statistics over several years of studies, the advantages of this laboratory work, recommendations for further improvement and formulates conclusions. [ABSTRACT FROM AUTHOR]

The functionality and complexity of modern electronic systems increases every year and poses new challenges not only to the industry, but to universities as well. Due to such a rapid development of complex electronics devices and systems university lecturers and professors are forced to deliver more advanced projects based on teamwork. In order for the students to accomplish projects successfully, university professors should have knowledge and practical skills in socia psychology, project management, successful team building. This article discusses an original and interactive successfu team building method, called "Puzzle" method--applicable with a self-assessment test, based on M. R. Belbir methodology. This team building method has been tested and applied for four years in Vilnius Gediminas Technica University Faculty of Electronics, accomplishing VLSI chip design projects. Data collected within four years from 6-students indicates, that the most successful projects were carried out by teams consisting of dominant Chairman Implementer, Completer-Finisher, and Specialist team roles, and as many as 84.4% of the surveyed students (26.6%--well 57.8%--excellent) positively accepted a synergy of the team that carried out the project. [ABSTRACT FROM AUTHOR]