学　术

　　为搭建我校博士后之间的学术交流平台，促进学术水平提升，学校博士后管理办公室组织开展博士后学术沙龙活动。本次沙龙由我校博士后张洪波、刘宇鹏和孙元华分享其研究成果，诚邀感兴趣的师生参加。

　　一、时　间：2017年12月15日（周五）14：30

　 二、地　点：清水河校区经管楼宾诺咖啡

　　三、主办单位：电子科技大学博士后管理办公室

　　四、承办单位：通信与信息工程学院

            电子科技大学博士后联谊会

　　五、活动安排：

　　报告一：

　　（1）主　题：100G-EPON Solutions in Future Optical Access Networks: Investigation of Low Cost and Power Consumption System Solutions

　　（2）主讲人：张洪波　通信与信息工程学院博士后 

　　（3）交流内容：

　　Internet of things (IoT), cloud services, web scale ecosystem, mobile front-haul (MFH) in the 5th generation mobile era (5G), and 4K/HD video are dramatically driving the increasing of bandwidth demand in broadband access networks. Cisco has reported that the internet traffic is expected to continue growing more than twice between 2016 and 2021, which means that the global internet traffic will be 105,800 GB per second in 2021. To satisfy theses enormous bandwidth requirements, IEEE 100G-EPON firstly recommends the 100-Gb/s based PON standard by exploring the technical proposal to achieve 25-Gb/s/λ。PON is a cost sensitive system, so we need to explore as low cost as possible solutions. The one based on commercial mature 10G optical devices is an alternative.

　　In our recently work, we have experimentally investigated a directly detection based 25-Gb/s downstream transmission performance over 20-km SSMF employed mainstream techniques, such as FTN-NRZ, PAM-4, EDB, and ODB, and adopted 10-GHz class optical devices without inline optical amplifier and dispersion compensation fiber (DCF). Unlike previous works, we used outperformance equalization technologies for band-limited NRZ-OOK, namely FTN-NRZ, to compensate band-limited impairment and fiber chromatic dispersion. What is more, considering the trade-off between cost and optical DSP, we also experimentally evaluated PAM-4, EDB and ODB transmission performance after 20-km SSMF transmission with the same line bit rate. Finally, we summarized all the experimental results together and found that FTN-NRZ outperforms the other modulations; However PAM-4 has more potential for the next generation 50-Gb/s/λ+ transmission. Our experimental results show that, FTN-NRZ, PAM-4, and ODB with FFE equalization meet 10G-EPON PR(x) 30 power budget requirement. FTN-NRZ with the beneficial of FFE and FTN technologies can achieved a receiver sensitivity of -27.18 dBm; while PAM-4 and ODB with FFE equalization achieved a sensitivity of -23.25 dBm. Whereas EDB and ODB without equalization could not satisfy the power budget requirement of PR(x) 30.

　　主讲人简介：

　　Hongbo Zhang received his B.S. and Ph.D. degrees in optoelectronic information and optical engineering from University of Electronic Science and Technology of China (UESTC), Chengdu, China, in 2006 and 2014, respectively. From 2006 to 2008, he worked toward the M.S. degree in optical engineering from UESTC. From July 2014 to July 2017, he worked in channel algorithm department in HUAWEI as an system engineer responding for optical DSP research of data-center interconnect and short range transmissions. Since July 2017, he has been with the School of Communication and Information Engineering, UESTC. His current research interests include electronic compensation of high-speed optical communication systems, short-range transmissions, next generation stage 2 passive optical networks, and communication radar integration, etc.

　　报告二：

　　（1）主　题：Tuning technology researches on microwave key passive component based on liquid crystal material

　　（2）主讲人：刘宇鹏　通信与信息工程学院博士后

　　（3）交流内容：

　　The research on liquid crystal tuning technology in the microwave band has important scientific significance in microwave radar, wireless broadband communications and other fields. It has become a research focus in the new interdisciplinary study.

　　Liquid crystal material is organic compounds between liquid and crystalline state, which has some advantages of both liquid and crystal. Based on the electro-optic effect, liquid crystal materials have birefringence and dielectric anisotropy in the microwave frequency band and have wide application prospects in microwave radar, precision guidance and wireless broadband communications and other fields. The liquid crystal material is applied to the microwave key passive components, which can realize the control of the center frequency broadband tuning, realize the dynamic frequency selection, expand the tuning range and bandwidth, and realize the miniaturization and light weight of the electronic system. It can be widely used in microwave systems such as communication, radar, tracking receiver and electronic countermeasures equipment. It is one of the focus directions in microwave field.

　　In the aspect of the tuning properties of liquid crystal materials, miniaturized resonance units and microwave key passive components, my research studies the physical properties of liquid crystal materials in the microwave frequency band, the liquid crystal tunable filters, the liquid crystal tunable filter integrated power divider, the liquid crystal tunable corrugated substrate integrated waveguide filters and the liquid crystal tunable antennas.

　　（4）主讲人简介：

　　Yupeng Liu is a post-doc majored in microwave and millimeter-wave circuits and systems. He obtained bachelor’s degree in Electromagnetic fields and wireless technology in UESTC, then performed PhD research in electromagnetic field and microwave technology advised by Prof. Ruimin Xu in UESTC. His research interests include liquid crystal microwave and millimeter-wave circuits and systems.

　　报告三：

　　（1）主　题：STUDY ON KEY TECHNOLOGY OF THE WIDEBAND ENDFIRE ANTENNA

　　（2）主讲人：孙元华 通信与信息工程学院博士后 

　　（3）交流内容：

　　In this talk, a novel monopole log-periodic antenna and 2GHz-18GHz end-fire monopole log-periodic antenna array is proposed . Through the study of classical monopole log-periodic antenna rigorous theoretical derivation for the radiation pattern was carried out. The theory of eliminating the stop-band of classical monopole log-periodic antenna array is also analyzed. The novel log-periodic monopole antenna uses the novel microstrip-to-slot transition as feed network, which has simple structure, wide band and easy to fabricate. The novel log-periodic monopole antenna array structure can achieve 100% band width. The proposed log-periodic antenna has wide band, simple structure, easy to fabricate, and exhibits good endfire radiation characteristics. The dissertation used two types of novel log-periodic monopole antennas (2GHz-6GHz, 6GHz-18GHz novel log-periodic antennas) to constitute an end-fire log-periodic monopole antenna array that cover 2GHz-18GHz. As the proposed log-periodic monopole antennas are conformal to missile surface, therefore the aerodynamic layout of the missile remains unchanged after antenna installation. The dissertation analyzed the wave diffraction characteristics with limited bottom, radiation characteristics of novel log-periodic monopole antenna with limited bottom and provide theoretical analysis for the design of the novel log-periodic monopole antenna.

　　主讲人简介：

　　Yuanhua Sun received the Ph.D. degree from the UESTC, in 2015. He currently works as a Postdoctoral Fellow in the School of Communication and Information Engineering. Dr. Sun is working in the field of microwave and network. His main research interests include end-fire antenna; RFID antenna , compacted antenna, network.

　　　　　　　　　　　　　　　　　　　　　　电子科技大学博士后管理办公室

　　　　　　　　　　　　　　　　　　　　　　　　2017年12月12日