A SiGe J-Band Gilbert Cell-Based Frequency Doubler and Power Amplifier Chain with 10 dBm Output Power

In this paper, we present the design and measurement results of a 220-294 GHz frequency doubler and amplifier chain for radar applications. The frequency doubler is implemented using a bootstrapped Gilbert cell, while the subsequent amplifier consists of three stages, designed as differential cascodes with tail current sources. This architecture ensures a full differential signal chain, providing high common-mode rejection. Using different breakout MMICs, we present measurement results of the entire chain and individual components. For the entire chain, a maximum output power of 10 dBm with a 3 dB bandwidth of 74 GHz was measured around the center frequency of 255 GHz. The circuit is designed in IHP's SG13G3 130 nm SiGe BiCMOS technology, which features heterojunction bipolar transistors with an ft and fmax of 470 GHz / 650 GHz, respectively.