An Ultra-Compact Differential D-Band Power Detector in a 90-nm BiCMOS Technology

With its large bandwidth, the D-band is a promising frequency range for high-data-rate mobile communication. As 6G communication systems evolve, reliable Built-In-Self-Test mechanisms are essential to ensure system integrity and performance throughout their operation. In this paper, we present an ultra-compact differential D-band power detector with a core area of only 130 µm × 80 µm. It is implemented in a 90-nm BiCMOS technology using heterojunction bipolar transistors featuring an f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf>/f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf> of 300 GHz/520 GHz. The detector employs a common-emitter topology. Integrating into a capacitively tapped transmission line enables daisy chaining, facilitating easy integration into a 50-ohm environment. The detector uses resistive emitter degeneration to linearize total input capacitance, mitigating intermodulation products in the passing signal caused by the transistor’s nonlinear input capacitance. This design achieves a flat amplitude response across the entire D-band with a square-law dynamic range of up to 24 dB.