Yoon Geon Kim

Design and analysis of a low-profile 28 GHz beam steering antenna solution for Future 5G cellular applications

A first-of-the-kind 28 GHz antenna solution for the upcoming 5G cellular communication is presented in detail. Extensive measurements and simulations ascertain the proposed 28 GHz antenna solution to be highly effective for cellular handsets operating in realistic propagating environments.

Design and testing of a millimeter-wave beam-steering mesh-grid array for 5 th generation (5G) mobile communication handset devices

Summary form only given. The steady advancement of silicon and compound semiconductor technologies has triggered the possibility of utilizing millimeter-wave frequencies for next-generation cellular data networks (“5G”). In comparison to 4G networks, the millimeter-wave 5G network offers significant advantage in data throughput due to the much wider RF bandwidth. Recent publications by other authors in (T.S. Rappaport, Y. Qiao, J.I. Tamir, J.N. Murdock, and E. Ben-Dor, Radio and Wireless Symposium, 2012, IEEE, pp. 151-154) have successfully demonstrated the possibility of a millimeter-wave cellular network by characterizing the propagation and angle-of-arrival for an adaptive beam-steering system operating at 38 GHz with full consideration of obstructions by foliage and other structures. However, the advent of an affordable, low-profile beam steering antenna remains one of the most critical issues for future 5G devices. Deployment of a beam-steering antenna array within a cellular handset device is unprecedented in the wireless community. This paper presents a first-of-the-kind phased-array which is specifically conceived for future millimeter-wave 5G cellular networks. The technical challenges associated with the inherent properties of the utilized 28 GHz frequency band and the real-life design constraints in the consumer electronics industry are identified and addressed. The well-understood laser and mechanical via structure within a high-volume printed circuit board technology is used to devise a novel mesh-grid patch antenna element topology. The presented mesh-grid patch features a fan-beam radiation characteristic with a o measured 3dB elevation beamwidth of more than 130 . The required horizontal 2 footprint is less than 3 x 1 mm which is smaller by several factors compared to a conventional Yagi-Uda or a planar dipole topology. Furthermore, the proposed antenna element does not require a ground fill-cut region, greatly alleviating the space constraints when integrating within a cellular handset device. The antenna element is further expanded into a beam-steering phased array configuration and integrated within a cellular handset prototype. The far-field radiation patterns of the mesh-grid array are first measured independently in the anechoic chamber and the procedure is subsequently repeated after integration with the 28 GHz RF transceiver unit. The maximum scanning angles for both measurements are controlled by adjusting the phase configurations of each antenna elements within the array. Measurements confirm the 28 GHz mesh-grid array exhibits a o maximum boresight gain of more than 10.5 dBi and ±170 scanning range in the azimuthal plane despite the degradations incurred due to the cellular handset chassis.

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.

60 GHz antenna module featuring spherical coverage for nomadic and mobile Gbps applications

Employing efficient, high directivity antennas is one of the most preferred techniques to alleviate the high material and atmospheric propagation loss which are commonly associated at millimeter-wave (mmWave) spectrum. Over the past decade, significant strides have been made in proliferating mmWave wireless technologies across a diverse range of user applications and markets. Consequently in addition to relatively well understood user scenarios such as mmWave backhaul and fixed point-to-point communication, the wireless industry has been actively investigating nomadic and mobile mmWave scenarios with focus on consumer electronics. For example, compact 60 GHz portable modules can be conceived in the form that resemble conventional USB dongles to support multi-Gbps wireless links for portable wireless devices. Mobile mmWave devises will most certainly be subject to frequent channel variations particularly due to constant orientation and position shifts. Extensive adaptive beamforming methodologies have been devised and researched by numerous research entities to ensure a secure wireless quality of service (QoS). However the effectiveness of mmWave adaptive beamforming algorithms are oftentimes diminished in non-line-of-sight (NLOS) propagation conditions which can eventually lead to wireless link failures. One of the primary factors that attribute to this practical but important technical challenge is the limited beam steering range associated with planar mmWave antennas such as broadside arrays. Ensuring high antenna gain across a wide range of atmosphere is subject to a series of technical tradeoffs and remains of the most elusive subjects in the mmWave wireless industry.

A planar, via-less zeroth-order antenna for wearable electrocardiography

Summary form only given. Wireless medical telemetry service is one of the fastest emerging technologies in healthcare industries worldwide. In addition, the proliferation of smartphones is currently serving as a catalyst to the increasing growth in this sector. Based on a secure, close-range wireless body area network (WBAN) which relays the patients physiological information to a nearby cellular device, a real-time monitoring system for those who require a relatively close medical attention can be realized. Among the physiological parameters, the pulse and the respiration rates are important indicators for wide range of healthcare applications ranging from recreational sports to wireless medical monitoring. Despite the significant advantages, the technical challenges of devising a wearable, sturdy health monitoring device with a reliable radio must be fully resolved. When operating at the industrial, medical and scientific (ISM) radio band, the antenna is expected to be one of the largest components within the device. It is imperative for the antenna to remain low-profile and yet be capable of exhibiting efficient radiation characteristics albeit the detrimental effects of the users body on the antenna matching and radiation. In this paper, a planar, zeroth-order resonance (ZOR) antenna is proposed for a wearable and detachable electrocardiography (ECG) sensor device. The profile of the proposed antenna topology is minimized using two distinctive techniques: 1.The elimination of vias unlike the conventional mushroom-shaped ZOR topologies. 2. Modeling of the radiator, series capacitance, shunt inductance and the ground on a single printed circuit board (PCB) layer. An air-bridge employed co-planar waveguide (CPW) structure is designed as the antenna feed network between the antenna element and the in-house low power 2.4 GHz RFIC. The overall dimension of the planar ZOR antenna is 15 mm × 9.6 mm × 3 mm when fabricated using a flexible PCB (İr = 2.2, tan = 0.02). The antenna is placed above the main board PCB of the ECG device and subsequently covered with flexible polycarbonate chassis. The radiation properties of the ZOR antenna within the assembled ECG device is studied by placing the device on the surface of the human body model with electrical properties as follows: Skin (ı=1.46 S/m, h=0.5mm), Body fat (ı=0.27 S/m, h=10.5mm), Muscle (ı=1.74 S/m, h=20mm) where h is denoted as the thickness. Simulation and measurements confirm a -10 dB S11 bandwidth of more than 80 MHz and a radiation efficiency of more than 30% in the presence of the human body. Overall, the ZOR antenna is confirmed to feature more than 3.5 m enhanced communication coverage and more than 20% higher antenna radiation efficiency in comparison to that using conventional chip antennas and monopoles under identical measurement conditions.

Radiation Efficiency-Improvement Using a Via-Less, Planar ZOR Antenna for Wireless ECG Sensors on a Lossy Medium

The critical issues involving severe radiation efficiency degradations during wireless electrocardiogram (ECG) health monitoring sessions are addressed by devising a monolithic zeroth-order resonance (ZOR) antenna. The presented antenna consists of a composite right/left-handed (CRLH) structure that is realized on a single, planar surface of the flexible printed circuit board (PCB) without the use of any via-holes. This significantly alleviates the complexity and fabrication cost involved with vertically polarized antennas with monopole-like radiation patterns, which are important factors in consumer electronics. Moreover, this letter investigates the practical issues associated with effects of the in-house designed ECG device circuit board, feeding mechanism with the RFIC, as well as the polycarbonate chassis. The finalized antenna is less than 0.12λ×0.08λ in total horizontal dimension with zero height profile. Measurement confirms the presented antenna features more than 30% radiation efficiency across 80 MHz bandwidth when completely integrated within the ECG sensor device and placed on the human body phantom.