A mobile WiMAX RF front-end module with integrated passive components and novel material

Abstract

System in package (SiP) plays an important role in the mobile communication market, while it can efficiently improve the size shrinkage, cost-effectiveness and available time of the products. Good achievements have been realized by other works in the past years, such as VCO, PA, BPF, Balun, Bluetooth module, and Wi-Fi systems with embedded passives [1-4]. Nowadays, the current trend is towards personal multi-media applications requiring high transmission data rate and mobility. Therefore, worldwide interoperability for microwave access (WiMAX) communication system is developed to meet the requirements. In this system, the operation of the wide channel bandwidth and the linearity of signals are the critical issue, especially in the circuit designs. This paper describes the design methodology of a RF front-end module with the modelling of embedded passive components that integrates with the power amplifier (PA), RF switch, BPF, and LPF circuit and operates over 2.3 - 2.7 GHz mobile WiMAX system. Additionally, the novel high-permittivity organic material with DK~20.8 at 2.4 GHz was also been developed. It minimizes circuit areas, greatly increases the quality factor of passive components and can be compatible with traditional PCB lamination process to reduce the production cost. By this material and multi-layers substrates realized by PCB process, the embedded passives largely replace SMDs including the inductors, capacitors, and filter components. The final designed embedded RF front-end produces 23 dB gain, better than 10 dB return loss in the TX path; and 2.5 dB noise figure with greater than 11 dB return loss in the RX path. Through the embedded technologies, 10 capacitors, 5 inductors, and 2 filters were embedded into the substrate, occupying almost 70.8 % of the total passive components, and the size of embedded front-end is less than 600 times 600 mil2. These technical results not only promote the technology of SiP but provide the solutions for the broadband mobile communication applications.