Wonbin Hong

Millimeter-Wave 5G Antennas for Smartphones: Overview and Experimental Demonstration

For the first time to the best of our knowledge, this paper provides an overview of millimeter-wave (mmWave) 5G antennas for cellular handsets. Practical design considerations and solutions related to the integration of mmWave phased-array antennas with beam switching capabilities are investigated in detail. To experimentally examine the proposed methodologies, two types of mesh-grid phased-array antennas featuring reconfigurable horizontal and vertical polarizations are designed, fabricated, and measured at the 60 GHz spectrum. Afterward the antennas are integrated with the rest of the 60 GHz RF and digital architecture to create integrated mmWave antenna modules and implemented within fully operating cellular handsets under plausible user scenarios. The effectiveness, current limitations, and required future research areas regarding the presented mmWave 5G antenna design technologies are studied using mmWave 5G system benchmarks.

Solving the 5G Mobile Antenna Puzzle: Assessing Future Directions for the 5G Mobile Antenna Paradigm Shift

Advances in antenna technologies for cellular hand-held devices have been synchronous with the evolution of mobile phones over nearly 40 years. Having gone through four major wireless evolutions [1], [2], starting with the analog-based first generation to the current fourth-generation (4G) mobile broadband, technologies from manufacturers and their wireless network capacities today are advancing at unprecedented rates to meet our unrelenting service demands. These ever-growing demands, driven by exponential growth in wireless data usage around the globe [3], have gone hand in hand with major technological milestones achieved by the antenna design community. For instance, realizing the theory regarding the physical limitation of antennas [4]-[6] was paramount to the elimination of external antennas for mobile phones in the 1990s. This achievement triggered a variety of revolutionary mobile phone designs and the creation of new wireless services, establishing the current cycle of cellular advances and advances in mobile antenna technologies.

Quantitative analysis of the effects of polarization and pattern reconfiguration for mmWave 5G mobile antenna prototypes

Real-time beam-steering of highly directive antennas at mmWave spectrum under unpredictable propagation environments remains a highly elusive challenge for the upcoming 5G era. Reconfigurable and multifunctional mobile 5G antenna and RF architectures which are desired to achieve sufficient QoS introduce additional technical and economic costs which may outweigh the benefits. This paper investigates the effects and relative significance of key antenna design parameters with QoS benchmarks based on real-life mmWave antennas integrated in fully operable 5G mobile device prototypes.

What will 5G Antennas and Propagation Be

Fifth-generation wireless technology, denoted as “5G” by the global wireless communications industry, seeks to accomplish multi-fold increases in key aspects of wireless communication. In conjunction with conventional microwave frequencies, millimeter-wave (mmWave) and THz frequencies and technologies are being investigated by major research institutions and industry. Deliberations are underway by regulatory officials around the world to authorize mmWave and sub-THz spectrum for 5G fixed and mobile applications. In the development of 5G communication systems, new propagation phenomena, novel multi-antenna transmitting architectures, and new mmWave operating frequency bands using much wider channel bandwidths than ever before are proving to be extremely effective ways to dramatically increase the communication data rate of future mobile communication networks. The papers in this special issue offer extensive insights and promising results that address many of the technical challenges that must be solved to usher in the 5G era.

High-Efficiency Crossed-Loop 4G LTE Antenna for All Display Metal-Rimmed Smartphones

A symmetrically crossed-loop antenna featuring very high radiation efficiency across the entire LTE frequency bands for metal-rimmed smartphones with only 2 mm ground clearance is proposed, analyzed, and verified. The employment of even and odd modes is utilized to achieve wide bandwidth across 698–960 MHz (low-frequency spectrum), 1710–2170 MHz (middle-frequency spectrum), and 2300–2690 MHz (high-frequency spectrum). Empirical analysis confirms the crossed-loop topology results in a 180° phase shift of the electric current distribution on the ground plane, resulting in enhancement of the radiation resistance. As a result, the devised LTE antenna exhibits more than 48% to 75% total system efficiency across the entire band of interest, which is the highest efficiency reported in literature for metal-rimmed smartphones with extremely small ground clearance.

OLED-embedded antennas for 2.4 GHz Wi-Fi and bluetooth applications

This is the first paper that demonstrates the possibility of utilizing transparent antennas to devise antennas with active display panels such LCDs and OLEDs with full invisibility. By using the entire region of an OLED of a smartwatch to devise a patch antenna, the radiation efficiency is confirmed to be maximized.

Optically Invisible Antenna Integrated Within an OLED Touch Display Panel for IoT Applications

Future electronics and Internet of Things devices with the capability of high-speed wireless communication will increasingly rely on efficient and intelligent antennas. However, conventional wireless communication systems for small wireless electronics devices suffer from low radiation efficiencies of miniaturized antennas implemented within less-than ideal locations and real estates. Here, we introduce the original concept of utilizing the entire transparent region of high-resolution organic light-emitting diode (OLED) touch displays to render an antenna that is invisible to the human eye. A transverse magnetic resonant mode antenna is formulated based on transparent conductive polymers, which are precisely realized using mesoscale formation of electromagnetic boundary conditions. Simultaneously, these electromagnetic patterns achieve optical invisibility. We show that the transparent antenna film can be integrated inside an OLED touch display and feature efficient radiation properties at 2.4 GHz. The presented theory and measurement studies of the fabricated prototype for smartwatch application for Wi-Fi and Bluetooth connectivity inspire a broader range of integration of microwave and display technologies.

Exploitation of Dual-Polarization Diversity for 5G Millimeter-Wave MIMO Beamforming Systems

For the first time, to the best of our knowledge, this paper reports a complete millimeter wave (mmWave) wireless system, which coherently utilizes polarization diversity, multi-input multioutput (MIMO), and beamforming technologies applicable for upcoming fifth generation wireless mobile terminals. Using an interdisciplinary approach across the entire layers constituting of antennas, RF architecture, and digital modem, the polarization of the presented mmWave beamforming antenna system dynamically adapts to the channel environments and MIMO transmission modes. Empirical investigations, which are taken under real-life environments, ascertain that implementing switchable dual-polarized array antennas can alleviate the complexity of the beam searching procedure and MIMO channelization. In addition, experimental results acquired from intensive system level tests indicate more than 22 dB averaged cross-polarization discrimination under polarized MIMO channel conditions at the 60 GHz band. The beam selection algorithm that can be easily implemented based on power metric is confirmed to feature a 99.5% accuracy in comparison with the optimal selection algorithm derived from the theoretical maximal capacity.