A 324-GHz Source/Modulator With $-$6.5 dBm Output Power

This paper presents a 324-GHz signal source/transmitter. Input signal of 81 GHz is applied to a differential pair for conversion to 324 GHz via two cascaded push-push frequency doublers. Stacked push-push configuration is used for enhancing the output power at 324 GHz and passive baluns with asymmetrical grounding stub is deployed to improve the power efficiency. The 81-GHz signal can correspondingly be modulated to function as a modulator. The proposed design is fabricated using 0.13- μm SiGe BiCMOS process. The total chip area is 0.95 mm ×1 mm. With the buffers, the total DC consumption is 42.5 mW. The maximum output power is -6.5 dBm at 324 GHz when the input power of the 81-GHz signal is of 0 dBm. The ability to transmit modulated signals has also been demonstrated in the proposed circuit.