This paper presents a highly linear 79 GHz differential low-noise amplifier (LNA) for civil-automotive radars operating at the predefined frequency range from 77 GHz to 81 GHz. The circuit is optimized for frequency-modulated continuous-wave (FMCW) radar application, which typically require a very high input-referred 1 dB-compression point (iP 1dB ). A reconfigurable differential common-source stage with capacitive neutralization is employed together with a common-gate stage in cascode configuration as the core of the LNA. The performance of the circuit can be easily adjusted within the gain-NF-P 1dB trade-off boundaries by changing the voltage at the back-gate terminal of the common-source stage, thus tailored to the application specific requirements. Passive baluns are placed at input and output to characterize the differential circuit with the available single-ended laboratory instrumentation. The LNA is implemented in a 22 nm FD-SOI CMOS technology. Its core is very compact with an area of 0.04 mm 2 . The fabricated chip is experimentally characterized in the lab, and it shows a peak gain of 8.7 dB at 80 GHz. From 75 GHz to 85 GHz, the measured input referred P 1dB (iP 1dB ) is about -6 dBm, and the minimum noise figure (NF) is 5 dB. Compared with the state-of-the-art for LNAs operating in a similar frequency range, the presented circuit shows the highest iP 1dB and has the most compact circuit core, together with an excellent NF and a moderate gain, resulting in the best figure-of-merit.
This paper presents a reflectometer with an integrated transducer as a high-integration miniaturized sensor for dielectric spectroscopy at 240 GHz in SiGe BiCMOS technology. The reflectometer consists of a signal generation component using 240-GHz multiplier chains, side-coupled directive couplers and a two-channel heterodyne receiver. Readout of the transducer upon exposure to liquids is performed by the measurement of its reflected signal using an external excitation source. The experimental dielectric sensing is demonstrated by using a binary methanol-ethanol mixture placed on the proposed on-chip dielectric sensor in the assembled printed circuit board.
The following study discusses the impact of hot-carrier degradation on high frequency performance of the 22nm FDSOI n-channel transistors. A quasi-static small-signal equivalent circuit MOSFET model is used to describe the device behavior. RF characteristics are extracted after stressing device with continuous DC. DC characteristics are also investigated thoroughly before and after stress. It is observed that, the device suffers from both interface damage and oxide defect. Accordingly, this study addresses how severe hot-carrier degradation affects the intrinsic parameters as well as the device performance.
Online community and groups often experience heated discussion. This paper examines a WeChat group discussion from the perspective of majority and minority influence to explore the evolvement of the discussion and the be-haviors of group members. Content analysis of 515 messages suggests that opin- ion conflicts between majority and minority evoke discussion engagement and knowledge exchange. There are different patterns of knowledge construction expressions between majority and minority groups. The majority prefer egocentric expression, while the minority prefer allocentric expression. Majority opinion holders have different conflict handling styles compared to minority opinion holders, who are more likely to avoid. Minority group is under great pressure in social interaction, they are easier to receive unfair comments and personal attacks.
We investigated whether fine-grained coordination in a screen-based puzzle task with a (virtual) partner would influence on-line perspective-taking. Participants played a screen-based puzzle game with a computer player. In the high-coordination condition, the player presented participants with puzzle pieces that could be placed near their partner’s last piece. In the low-coordination condition, pieces could only be placed further away from their partner’s last piece. Participant’s eye movements were then measured in a referential communication task, with the partner giving the instructions, and whether possible competitor referents were in shared or privileged ground. The results demonstrate clear effects of ground and coordination. Participants in both coordination groups were sensitive to the perspective of the interlocutor. In addition, participants in the high-level coordination condition were more sensitive to statistical regularities in the input and their comprehension was more time-locked to the utterance of the speaker.
Online platforms provide a public sphere for discussion, debate, and deliberation among citizens. The engagement of online deliberation enables participants to exchange viewpoints and form communities. This paper aims to explore the influencing factors on engagement level of online deliberation by examining the relationship between an initial post’s content features and length and the engagement of the discussion thread it initiates. We sampled 254 discussion threads with 254 initial posts and 2934 following posts and conducted quantitative and qualitative analysis of the posts. Findings show that initial posts which are longer and allocentric (as opposed to egocentric) would evoke longer following posts in a discussion. Different content type (social interaction, claim, argument) of initial posts would lead to significant different engagement, arguments would trigger higher level engagement (average posts per participant and average length of posts in discussions). Whether an initial post holds a clear position has no significant impact on discussion engagement. These findings contribute to a deeper understanding of online deliberation and its engagement and can be useful in promoting engagements in online deliberation.
