  Information Metasurface, also known as reconfigurable intelligent surface
(RIS) has gained significant attention owing to its impressive abilities in
electromagnetic (EM) wave manipulation with simple structures. Numerous studies
focus on achieving efficient and versatile information transmission using RIS
across various fields like wireless communication, radar detection, integrated
sensing, and communications, among others. Previous studies demonstrate diverse
approaches to achieve reflection modulation by utilizing the superposition of
the quantified reflection coefficient (RC) of each unit but suffer from the
computing complexity of codebook sequence, the safety of communication, and the
flexibility of modulation. To address these challenges, we introduce a novel
concept of information metasurface, namely AWG-RIS, which is capable of
independently producing arbitrary baseband waveforms and beam patterns through
a design that decouples magnitude and phase, without changing the beam pattern.
The AWG-RIS functions as a reflection mixer, directly embedding the intended
signal into the incoming EM waves. Subsequently, we developed an analysis
framework and introduced the waveform factor and beamforming factor into the
new model, offering theoretical support for the transition from the control
signal to the outgoing electromagnetic wave. Additionally, we unveil the
world's first prototype showcasing passive arbitrary waveform generation while
maintaining the beam pattern unaltered. Leveraging the decoupling of direct
modulation and beamforming, we explore additional applications in several
domains relative to traditional RISs. Finally, we present experiments that
confirm the generation of arbitrary waveforms and particular spectrograms.
