Miniature Integrated 2.4 GHz Rectennas Using Novel Tunnel Diodes

This work presents the design, fabrication, and measured results of a fully integrated miniature rectenna using a novel tunnel diode known as the Asymmetrical Spacer Layer Tunnel (ASPAT). The term rectenna is an abbreviation for a rectifying antenna, a device with a rectifier and antenna coexisting as a single design. The ASPAT is the centrepiece of the rectifier used for its strong temperature independence, zero bias, and high dynamic range. The antenna is designed to be impedance matched with the rectifier, eliminating the need for a matching network and saving valuable real estate on the gallium arsenide (GaAs) substrate. The antenna is fully integrated with the rectifier on a single chip, thus enabling antenna miniaturisation due to the high dielectric constant of GaAs and spiral design. This miniaturisation enables the design to be fabricated economically on a GaAs substrate whilst being comparable in size to a 15-gauge needle, thus unlocking applications in medical implants. The design presented here has a total die size of 4 x 1.2 mm(2), with a maximum measured output voltage of 0.97 V and a 20 dBm single-tone 2.35 GHz signal transmitted 5 cm away from the rectenna.

Automated summary

This work introduces a fully integrated miniature rectenna design that utilizes the unique ASPAT tunnel diode. The ASPAT provides temperature independence, zero bias, and high dynamic range for the rectifier. By integrating the antenna and rectifier on a single chip, impedance matching is achieved, eliminating the need for a matching network and saving space on the GaAs substrate. The miniaturization enabled by the GaAs material allows for economical fabrication and potential applications in medical implants. The design features a die size of 4 x 1.2 mm², achieving a maximum measured output voltage of 0.97 V and successful transmission of a 20 dBm single-tone 2.35 GHz signal at a distance of 5 cm from the rectenna.