A 135-190 GHz Broadband Self-Biased Frequency Doubler using Four-Anode Schottky Diodes

Area of Science:

• Electrical Engineering
• Terahertz Technology
• Semiconductor Devices

Background:

• Traditional frequency multipliers often require complex bias circuitry.
• Achieving broadband operation at terahertz frequencies presents significant design challenges.

Purpose of the Study:

• To design and demonstrate a self-biased broadband frequency doubler operating in the 135-190 GHz range.
• To validate the feasibility and effectiveness of a self-bias scheme for Schottky diode frequency multipliers.

Main Methods:

• Utilized micron-scaled planar Schottky diodes with specific anode area and epitaxial layer thickness.
• Developed a 3D-Electromagnetic (EM) model of the Schottky diode to extract parasitic parameters.
• Implemented broadband matching elements including waveguide steps and suspended microstrip lines.

Main Results:

• Achieved a 34% 3 dB bandwidth from 135 GHz to 190 GHz.
• Demonstrated a conversion efficiency above 4% with 100 mW input power.
• Measured a peak output power of 17.8 mW at 166 GHz with 10.2% efficiency.

Conclusions:

• The self-bias scheme is a feasible and effective approach for Schottky diode-based frequency multipliers.
• The designed doubler offers broadband performance without external bias, simplifying terahertz system integration.
• The results align well with simulations, confirming the design's accuracy and potential.