Radio frequency devices are the core of wireless connection, and radio frequency devices are necessary where wireless connection is required. Driven by IoT applications, the number of global wireless connections will increase exponentially in the future. Qualcomm predicts that by 2020, the number of wirelessly connected terminal devices worldwide will exceed 25 billion. The demand for wireless connectivity continues, and opportunities in the RF device industry continue. There are more and more wireless connection protocols equipped with mobile phones, directly driving the continuous growth of the radio frequency device industry. From the early 2G single communication system to the current 2G, 3G, 4G, wifi, Bluetooth, nfc, FM, mobile phones need to support more than 7 wireless communication systems, and the value of a single radio frequency device is several times that of the system ten years ago. 5G evolution is a gradual process, and innovative radio frequency device technology is expected to be applied in 4.5/4.9G. In the evolution process from 2G to 3G, wireless communication has experienced three stages: UMTS, HSPA, and HSPA+; the evolution process from 3G to 4G has experienced three stages: class 1-2, class 3-4, and class 5. We believe that the evolution to 5G is also a gradual process, which will experience intermediate forms such as 4.5G/4.9G. And in these intermediate forms (around 2018), there will be some radio frequency technologies to achieve commercial applications. Radio frequency devices have important applications in the consumer electronics and military industries, and the importance of industrial capital and national funds will increase day by day. With the help of capital from all parties, the domestic RF device industry will usher in a new round of industry development opportunities. PA chip field: The PA chip industry welcomes two major dividends: interface standardization and the transfer of GaAs wafer foundry to China. The product development and production process of domestic PA manufacturers is smoother. It is expected that the domestic substitution rate in the 5G era will increase significantly. At present, a number of outstanding PA manufacturers such as Han Tianxia, ​​Zhongpu Micro, RDA have emerged in China.