Radio frequency devices are the core of wireless connections and are essential in any location that requires wireless connectivity. Driven by the application of the Internet of Things, the number of global wireless connections will grow exponentially in the future. Qualcomm predicts that by 2020, the number of wireless connected terminal devices worldwide will exceed 25 billion. The demand for wireless connections is not limited, and opportunities in the RF device industry are constantly emerging. The increasing number of wireless connection protocols equipped with mobile phones directly drives the continuous growth of the RF 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 RF devices per device is several times that of systems from ten years ago. The evolution of 5G is a gradual process, and innovative RF device technology is expected to be applied in 4.5/4.9G. During the evolution from 2G to 3G, wireless communication has gone through three stages: UMTS, HSPA, and HSPA+; The evolution process from 3G to 4G has gone through three stages: class 1-2, class 3-4, and class 5. We believe that the evolution towards 5G is also a gradual process, going through intermediate forms such as 4.5G/4.9G. Among these intermediate forms (around 2018), some RF technologies will be commercialized for application. Radio frequency devices have crucial applications in the consumer electronics and military industries, and the importance of industrial capital and national funds will continue to increase day by day. With the support of various capital, the domestic RF device industry will usher in a new round of industry development opportunities. PA chip field: The PA chip industry is experiencing two major dividends: interface standardization and the transfer of gallium arsenide wafer foundry to China. Domestic PA manufacturers have smoother product research and production processes, and it is expected that the domestic substitution rate will significantly increase in the 5G era. At present, a group of excellent PA manufacturers such as Hantianxia, Zhongpu Micro, RDA have emerged in China.