Monolithic Integration of Broadband MUTC-PD Coupled With Novel Terahertz Antenna

This work presents a broadband terahertz emitter by monolithically integrating a modified uni-traveling-carrier photodiode (MUTC-PD) with a novel CROWN antenna. The MUTC-PD, featuring optimized epitaxial layers and reduced contact resistivity ( $4\times 10.6 \Omega \cdot $ cm2), achieves a simulated 3dB bandwidth of 230 GHz. The CROWN antenna employs fractal circular structures to generate dense resonance frequencies, enabling wideband operation (0–600 GHz) with 11 reflection coefficient (S11) minima below −20 dB. Experimental results demonstrate a 3dB bandwidth >190 GHz and 10dB bandwidth >400 GHz under −2 V bias and 7 mA photocurrent, aligning closely with simulations.