Design and implementation of two different RF SiPs for micro base station

Today a range of wireless communication products have the requirement of achieving a higher integration level. In this paper, we propose two RF SiPs based on a RF prototype board for micro base station. The two RF SiPs integrate a complete 700-2600MHz RF system that includes transmitter, receiver, and feedback module, ADC/DAC and clock module. RF SiP 1 consists of two multilayer organic substrates, which are vertically stacked by using Ball BGA interconnections. RF SiP 2 uses flexible substrate as the interconnections between the top and the bottom substrates. Compared with the original RF part on the prototype board (20cm×25cm), the size of the two RF SiPs is 5.25m×5.25cm, almost reducing system area 20 times. By comparison, the flexible substrate on RF SiP 2 provides better transmission quality of input RF signals and RF SiP 2 shares better thermal performance. Besides, the RF SiP 1 uses more conventional processes and has the potential to be fabricated with a lower cost.