Compact On-Chip Quadruplexer Using Lumped Elements on Integrated Passive Device Process

This paper presents an on-chip miniaturized quadruplexer implemented on the silicon-based integrated passive device (IPD) process. The proposed quadruplexer consists of four building blocks each associated with two cascade parallel LC resonators and an extra π-network as the last stage. Due to the open circuit condition the LC tanks provided and the impedance transforming capability of the π-network, each block is invisible in three of the four operating bands but serves as a well-matched 50-Ω line in the remaining one. Without the help of matching section, the quadruplexer features a very impressive circuit size while still keeps good electrical responses.