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21. Bandwidth Optimization of Doherty Power Amplifier Based on Source Converters for 5G Mobile Handsets.

Author

Imai, Shohei, Mukai, Kenji, Tanaka, Satoshi, and Okabe, Hiroshi

Subjects
POWER amplifiers, CELL phones, NUMERICAL solutions to differential equations, 5G networks, BANDWIDTHS, DESIGN techniques
Abstract

In this study, wideband Doherty power amplifiers (DPAs) based on converters comprising one transformer and two capacitors are investigated. Moreover, the parallel and series-type Doherty combiners are investigated. The series-type Doherty combiner is shown to have wider characteristics than the parallel-type converter-based Doherty combiner via numerical analysis. An approximate analysis was applied to the series-type combiner, and a quasi-optimum design parameter was derived for wideband matching. A quasi-optimum design parameter was compared with a true optimum solution derived by numerical analysis, and its certainty was verified. A combiner with parameters close to the true optimum solution was designed and evaluated. A DPA fabricated using this combiner was adequately small for a 5G mobile handset and could be operated in the frequency range of 2.2–2.7 GHz with efficiency exceeding 35% and a sufficiently low distortion under an amplifying wideband modulated signal [fractional bandwidth (FBW): 4% = 0.1/2.5 GHz]. The proposed combiner and its design techniques helped in designing a compact and long battery life of 5G mobile phones with high data throughput at a few gigahertz frequency ranges. [ABSTRACT FROM AUTHOR]

Published
2022
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31. 800-MHz Bandwidth Signal Transmission with Radio over Multi-Mode-Fiber for Cascaded IFoF-Based C-RAN Mobile Fronthaul.

Author

Yasuda, Hiroki, Aiba, Takamitsu, Tanaka, Satoshi, Suzuki, Toshinori, Ishimura, Shota, Tanaka, Kazuki, Nishimura, Kosuke, Kao, Hsuan-Yun, Wakabayashi, Tomohiro, and Kawanishi, Tetsuya

Abstract

We report the signal transmission with an analog radio over multi-mode fiber (A-RoMMF) subsystem using a single-mode vertical cavity surface emitting laser and a cost-efficient bias-tee consisting of a coupling transmission line with an electrical circuit pattern. The frequency response of the coupling transmission line has a slope inverse to that of the A-RoMMF subsystem at the 28-GHz band to suppress the channel power difference of two component carrier signals for 800-MHz bandwidth signal transmission through a 200-m long multi-mode fiber (MMF). The evaluation was performed using 5th generation new radio (5G-NR) 64 quadrature amplitude modulation (64-QAM) orthogonal frequency division multiplexing (OFDM) signals with a center frequency of 28 GHz, two component carrier (CC), a bandwidth of 400 MHz/CC and subcarrier spacing of 120 kHz. Furthermore, we demonstrate the transmission of 5G-NR 64-QAM OFDM signals with two carrier component, a bandwidth of 400 MHz/CC and subcarrier spacing of 120 kHz signals when the novel A-RoMMF subsystem is adapted to a cascaded intermediate frequency over fiber based centralized radio access network mobile fronthaul system with a 200-m long MMF and 5-m distance wireless transmission. [ABSTRACT FROM AUTHOR]

Published
2021
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32. Joint Extraction of Retinal Vessels and Centerlines Based on Deep Semantics and Multi-Scaled Cross-Task Aggregation.

Author

Xu, Rui, Liu, Tiantian, Ye, Xinchen, Liu, Fei, Lin, Lin, Li, Liang, Tanaka, Satoshi, and Chen, Yen-Wei

Subjects
COMPUTER-aided diagnosis, RETINAL blood vessels, RETINAL imaging, SEMANTICS, IMAGE segmentation, DATA mining, TASK performance
Abstract

Retinal vessel segmentation and centerline extraction are crucial steps in building a computer-aided diagnosis system on retinal images. Previous works treat them as two isolated tasks, while ignoring their tight association. In this paper, we propose a deep semantics and multi-scaled cross-task aggregation network that takes advantage of the association to jointly improve their performances. Our network is featured by two sub-networks. The forepart is a deep semantics aggregation sub-network that aggregates strong semantic information to produce more powerful features for both tasks, and the tail is a multi-scaled cross-task aggregation sub-network that explores complementary information to refine the results. We evaluate the proposed method on three public databases, which are DRIVE, STARE and CHASE_DB1. Experimental results show that our method can not only simultaneously extract retinal vessels and their centerlines but also achieve the state-of-the-art performances on both tasks. [ABSTRACT FROM AUTHOR]

Published
2021
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37. Visualization technique of maintenance work with a motion capture sensor

Author

Tanaka Satoshi, Tsuyoshi Moriya, Munehito Kagaya, and Hidefumi Matsui

Subjects
0209 industrial biotechnology, Engineering, business.industry, Work (physics), Process (computing), 02 engineering and technology, Maintenance engineering, Preventive maintenance, Motion capture, Motion (physics), Visualization, 020901 industrial engineering & automation, Atmospheric measurements, Computer vision, Artificial intelligence, business
Abstract

A motion capture technique was developed to record a worker's motion during preventive maintenance, especially during the wiping process of wet cleaning. The time-series three-dimensional coordinal data of a worker's hand was successfully obtained with a motion capture sensor, and three different possible movements were distinguished. In addition, the data was correlated with the change in the number of particles on the surface of a chamber part before and after wiping. These results indicate that key indicators of high-quality maintenance work can be extracted from workers' motions using this technique.

Published
2016

38. Cost-Effective and Time-Efficient Failure Analysis Method for Yield Enhancement Utilizing Picked Sawn Wafer.

Author

Yanagita, Hiroshi, Jingu, Akihito, Okanishi, Shinobu, Tanaka, Satoshi, and Koyama, Toru

Subjects
INTEGRATED circuits, TEST systems, HIGH temperatures, PRODUCT costing, FAILURE analysis, FAULT diagnosis, BATCH processing, ADHESIVE tape
Abstract

Electrical and physical failure analyses have played a key role in the yield enhancement of large-scale integrated circuits. However, the growing cost of product wafers has progressively hindered their use for analysis, depending on the shrinkage of device dimensions. To overcome these difficulties, we propose a new analytical style that uses the remaining dies on a sawn wafer after all the good dies have been picked and taken for assembly. We call the resulting structure a “skeleton-wafer”. In the present study, we have developed a testing system that can handle a skeleton-wafer in the same manner as a conventional wafer. Basically, skeleton-wafer testing is performed at room temperature, given that commonly used dicing tapes have low heat-resistance. We have also developed a sophisticated method that enables analytical testing on the remaining dies at high temperature. A case example achieves high throughput and good contact characteristics, enabling the developed system to be of practical use in high-volume electrical failure analysis. We illustrate how our analytical testing system has improved cost-effectiveness and time-efficiency in yield enhancement activity. [ABSTRACT FROM AUTHOR]

Published
2019
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