Recent progress of the development of a long pulse 140GHz ECRH system on EAST Handong Xu, Xiaojie Wang, Jian Zhang, Fukun Liu, Yiyun Huang, Jiafang Shan, Weiye Xu, Miaohui Li, J. Lohr, Y.A. Gorelov et al. (16 more) EPJ Web Conf., 203 (2019) 04002 Published online: 25 March 2019 DOI: 10.1051/epjconf/201920304002