Graphene/AlGaN/GaN RF Switch.

Area of Science:

• Materials Science
• Electrical Engineering
• Solid-State Physics

Background:

• Radio frequency (RF) switches are crucial components in modern electronic systems.
• Existing RF switch technologies face limitations in high-frequency performance and integration.
• Graphene and AlGaN/GaN systems offer promising properties for advanced electronic devices.

Purpose of the Study:

• To propose and investigate novel RF switches utilizing graphene and a two-dimensional high-density electron gas (2DEG) in the AlGaN/GaN system.
• To evaluate the performance of these switches across a wide frequency range (10 MHz to 114.5 GHz).
• To assess the integration compatibility and potential applications in time-modulated systems.

Main Methods:

• Fabrication of RF switches integrating graphene and 2DEG within a coplanar waveguide structure.
• Measurement of switch performance, including on-state insertion losses, switching times, and on-off ratio.
• Characterization across a broad frequency spectrum from 10 MHz to 114.5 GHz.
• Development of an equivalent circuit model to describe switching characteristics.

Main Results:

• Switches demonstrated functionality from 10 MHz to 114.5 GHz, with on-state insertion losses ranging from 7.4 to 19.4 dB.
• An approximate 4 dB on-off ratio was observed above 70 GHz, indicating continued switching capability.
• Fast switching times were achieved, with rise and fall times around ~25 ns and ~17 ns, respectively.
• The switches can provide up to 20 MHz of bandwidth in time-modulated systems.

Conclusions:

• The proposed graphene and 2DEG RF switches are effective across a wide frequency range, including millimeter-wave frequencies.
• Integration into coplanar waveguides simplifies system implementation and avoids matching issues.
• The demonstrated performance, particularly bandwidth in time-modulated systems, is significant.
• The developed equivalent circuit model aids in the design of optimized switches for specific applications.