24.1 A 90-to-180GHz APD-Integrated Transmitter Achieving 18dBm Psat in 28nm CMOS

The THz frequency band offers an exceptionally wide bandwidth, making it ideal for ultra-high-data-rate communication using simple modulation schemes like amplitude-shift-keying (ASK) [1–5]. By avoiding complex modulation schemes, we can simplify the THz system architecture, reducing the complexity of analog mixed-signal processing components, including high-speed multi-bit ADCs and DACs, which tend to be power-hungry and area-consuming. However, challenges arise due to amplitude nonlinearity, which can significantly reduce data rates in ASK systems. To address this, digital processing techniques such as equalization (EQ) and digital pre-distortion (DPD) become necessary [4, 5], which would result in a bulky system with substantial power consumption at the THz frequency band. Furthermore, based on the silicon process, the limited output power available at the THz frequency band imposes constraints on wireless communication link distances.