Future Internet-of-Things (IoT) networks demand scalable, energy-efficient, and intelligent wireless nodes with integrated sensing and communication (ISAC). Conventional transmitter architectures rely on complex and power-hungry radio-frequency (RF) chains, limiting their suitability for dense IoT deployment. This work presents a programmable millimeter-wave information metasurface (mmWave-InfoMeta) transmitter enabling compact, low-cost, and reconfigurable operation for IoT applications. The mmWave-InfoMeta directly modulates information onto multiple carrier frequencies using programmable modulation schemes, allowing adaptive operation across diverse IoT environments. With its array characteristics, the metasurface-based transmitter supports dynamic switching between SISO and MIMO modes, enabling space and frequency division multiplexing, while also integrating real-time user localization without the need for additional hardware. Experiments demonstrate a closed-loop ISAC platform capable of adaptive beamforming for signal enhancement. The proposed mmWave-InfoMeta offers a lightweight and multifunctional transmitter solution for large-scale and intelligent IoT systems.

Three-dimensional (3-D) printing, also known as additive manufacturing, provides a novel and cost-effective approach for implementing microwave devices. With the rapid advancement and improved manufacturing resolution of the 3-D printing technology, additive manufacturing has enabled the design and fabrication of electronic devices in higher terahertz (THz) frequency bands, contributing to bridging the gap between microwaves and photonics. Simultaneously, metalenses have garnered significant attention due to their ability to shape electromagnetic (EM) wavefronts. Metalens technology offers a promising solution for wave focusing, surpassing traditional dielectric lenses with advantages such as reduced weight and low loss, particularly at THz frequencies. In this article, we present an overview of the development of 3-D-printed THz metalenses, ranging from single metalenses to dual-layer and trilayer configurations. The functionality of the metalenses becomes more powerful, from replacing conventional light-focusing dielectric lenses for single-layer metalenses, achieving 2-D beam scanning, holographic imaging, and reconfigurable orbital angular momentum (OAM) for dual-layer metalenses, to enabling 3-D focus scanning for trilayer metalenses. We also discuss practical measurement technologies for THz metalenses and briefly outline the prospective to propel the 3-D-printed metalens technology forward.