A Tunable SiGe BiCMOS Gain-Equalizer For X-Band Phased-Array RADAR Applications

This paper presents a compact-size tunable gain-equalizer for X-Band Phased-Array RADAR applications in a 0.25μm SiGe BiCMOS technology. An isolated NMOS based variable resistance was used for the first time to tune the slope of the gain-equalizer. For NMOS, an isolated body created by a deep n-well was utilized to reduce insertion loss due to the substrate conductivity. Furthermore, the power-handling capability of the tunable gain-equalizer was improved thanks to the resistive body-floating technique. The designed tunable gain-equalizer operates in the frequency range from 8 to 12.5 GHz with a measured positive slope of 1 dB/GHz and 1 dB tunable slope. The effective chip area excluding the pads is 0.21 mm2, and the total area including pads is 0.31 mm2. To authors best knowledge, this study is the first tunable gain-equalizer in SiGe technology presented for X-band phased-array RADAR applications.