Time-modulated metasurfaces with both amplitude and phase control ability at carrier frequency

Area of Science:

• Electromagnetics
• Metamaterials
• Signal Processing

Background:

• Time-modulated metasurfaces (TMMS) offer flexible beam manipulation but often suffer from operation at undesired harmonic frequencies.
• This harmonic operation limits their practical utility in real-world applications.

Purpose of the Study:

• To propose and investigate a novel method enabling TMMS to achieve beam-forming at the fundamental carrier frequency.
• To demonstrate independent control over both amplitude and phase for each metasurface element.

Main Methods:

• Utilizing a reconfigurable metasurface (MS) for phase control.
• Introducing time modulation (TM) amplitude excitation via an anti-phase modulation time sequence (APMTS).
• Theoretical analysis and experimental validation using a 10x10 1-bit TMMS prototype.

Main Results:

• The proposed method allows for independent and simultaneous control of amplitude and phase at the carrier frequency.
• A new rigorous efficiency definition for TMMS is introduced and analyzed.
• The method demonstrates higher TM efficiency in beam-forming compared to conventional techniques.

Conclusions:

• The developed method provides a clear, simple, and implementable solution for carrier-frequency beam-forming with TMMS.
• This breakthrough enhances TMMS practicality for potential applications in wireless communications, target sensing, and radar systems.