Embedded duplexer implementation for WiMAX front-end module with organic package substrate

In this paper, low cost and highly compact duplexers are investigated for dual-band WiMAX FEM (front-end module) with multi-layered organic package substrate. This dual band FEM includes a duplexer and 2,5 GHz power amplifier die. To achieve small module for mobile applications, FEM should have a tiny PKG form factor. In addition to module size limitation, FEM requires higher gain and stringent attenuation specification for reducing RF interference from a frequency overlap. To implement low cost and highly compact FEM, an effective solution is to embed passive components inside PCB. The embedded duplexer was designed on 8 layer organic substrates for finding out efficient structure and verifying FEM specifications. This components design implemented by using ADS and HFSS. The dual-band FEM with embedded passive components incorporates duplexer including 2GHz, 5GHz BPFs. Integrated dual-band BPFs show an insertion loss of <-2.0dB in path band and 20dB attenuation performance in rejection band. Since conventional PCB process has higher tolerance than semiconductor process, it is important to control process tolerance. The measured results of BPFs and duplexer show good electrical performance with low insertion loss, high attenuation. Embedded passive Packaging technology has many advantages such as improving packaging efficiency and better electrical performances for low cost and highly compact RF SOP (System on Package) applications.