Lange coupler design for Si-ICs up to 170GHz in 0.13um SiGe BiCMOS

A design approach of Lange coupler for Si-substrate monolithic microwave integrated circuits is presented for frequency range up to 170 GHz. A combination of odd- and even-mode impedance theory and 3D EM simulation is proposed to improve the performance of Lange coupler. The value of the even number of the strip lines is determined based on the even-mode impedance calculation according to the process design rule in this work. Test structures have been fabricated in a 0.13 um SiGe technology. Measured result is in quite good agreement with simulated result.