Design of an 8×8 SiGe BiCMOS Butler Matrix

In this paper, an innovative design of an on-chip 8 × 8 Butler matrix (BM) in SiGe BiCMOS technology is proposed. The BM is designed for 24 GHz ISM radar indoor applications and it is implemented using the BiCMOS9MW ST Microelectronic process, which is a standard 130 nm SiGe BiCMOS technology. The configuration presented in this work, thanks to the miniaturization of the quadrature hybrid implemented using an intertwined transformer, results extremely compact. Indeed, it was possible to achieve a considerable reduction of the chip area which is equal to 714 um × 650 um. The BM was prototyped and experimentally validated using a dedicated test board. The measured results show good performance both in terms of phase linearity and in terms of operating bandwidth.