Hao developed integrated antenna solutions using novel materials for security, aerospace, and healthcare, such as
lens antennas for satellite communications and
supply chain establishment. He co-developed stable active non-Foster metamaterial for small antennas and coined the term "
body-centric wireless communications," which involves integrating wearable and implantable sensors. His early research in metamaterials,
transformation optics, and
AI-driven
robotics for precise wave control has impacted electromagnetic devices and medical communication technology. This work has been featured by media outlets such as
CNN,
Telegraph,
Financial Times, and
IEEE Spectrum.
Body-centric wireless communications and wearable antennas In 2003, Hao and his colleague conducted research, becoming the first to explore the characterization of the human body as a communication medium. Their work revealed that radio signals travelling across the body's surface experience considerable signal loss and variations in propagation time, known as dispersion. He noted that antennas placed on the body suffer from decreased efficiency, altered radiation patterns, and impedance fluctuations. To address these challenges, his focus shifted towards using surface and creeping waves for on-body communication among sensors. Concurrently, he developed a theoretical framework for modeling these waves in the presence of the human body and proceeded to design antennas tailored for reliable on-body communication, utilizing precise and realistic models. In addition to on-body channel modelling studies, Hao pioneered the exploration of on-body antennas across frequencies ranging from 10 MHz to 100 GHz. His research laid the foundation for designing low-profile antennas capable of reliably facilitating on-body communications, and engineered various body-worn antennas featuring spatial diversity at UHF/VHF and UWB frequencies. In particular, antennas operating at 60GHz and 94GHz were developed to support on/off-body communications, particularly in defense and healthcare sectors. Throughout his research journey, he has developed RF modeling methods tailored for body-centric wireless communication. He integrated Huygens' principle into FDTD algorithms for precise analysis of on-body
radio propagation, and while emphasizing the significance of human-specific modelling, devised commercial tools for designing wearable and implantable sensors.
Metamaterials and transformation optics To support his efforts in antenna design, Hao pioneered the development of a set of computational tools in 2005 for modelling microwave metamaterials. He also explored the properties of a hyperbolic wire medium lens, which contributed to the reduction in mass, footprint, and profile of reconfigurable intelligent surfaces (RIS). His work on metamaterials and transformational optics, published in leading journals such as
Physics Review Letters,
Nature Communications, and
IEEE Transactions, focused on applications to antennas and propagation. Notably, in 2018, his collaborative research introduced an approach to antenna design utilizing transformation optics. In 2009, he developed a manufacturing process for free-formed 3D woodpile structures operating at sub-THz frequencies, initially utilized for concealed weapon detection and later realized through 3D additive manufacturing.
Antenna design and integration of emerging technologies Hao's later work has focused on innovating antenna design, materials science, and integrating
emerging technologies like machine learning into electromagnetics. He introduced a concept involving hyperuniform disordered antenna arrays and metasurfaces to enhance spectral and spatial performance. Employing
Natural Language Processing (NLP) tools, he applied machine learning techniques to forecast trends in antennas and propagation research using vast
unstructured data. Additionally, in two journal papers published in
Advanced Science and
npj Computational Materials, he applied unsupervised
deep learning to identify disordered material signatures in perovskites, facilitating predictions on crystal symmetry and phase transitions, and introduced a graph-based machine learning model to analyze material properties, advancing computational materials for antenna applications. ==Awards and honours==