Rapid progress in plasmonics is driven by the ability to enhance near-field effects with subwavelength localization of light. Recently, we observe the emergence of a new branch of nanophotonics aiming at the manipulation of strong optically-induced electric and magnetic Mie-type resonances in dielectric and semiconductor nanostructures with high refractive index. Unique advantages of dielectric resonant optical nanostructures over their metallic counterparts are low dissipative losses, low heating, and the enhancement of both electric and magnetic fields. In this talk, I will review this new emerging field of nanophotonics and metasurfaces and demonstrate that Mie-type resonances in high-index dielectric nanoparticles and subwavelength structures can be exploited for new physics and novel functionalities of photonic structures especially in the nonlinear regime.

One-sided directional slot antenna and high-efficient CMOS class-E power amplifier (PA) and for 5GHz constant envelope modulation scheme were developed. The antenna was composed of top antenna metal layer and bottom floating metal plane. By using the difference of the top and bottom resonant frequency, we can realize one-sided directional radiation. The proposed class-E PA employs injection-locking technique to reduce the required DC input power. 0.18 um CMOS process was used for fabrication. This PA was placed on the lead frame and molded in the packaging for transmitter application. In our design, the position and length of the bonding wires are optimized by using EM simulation. In addition, a coplanar waveguide structure was realized by the bonding wires in the RF port.

It is well-known that RF power amplifier is the key active component in various wireless communication and active phased array radar systems, and it is always required for high power output with high reliability. Unfortunately, for most LDMOSFET-, GaAs HBT-, and AlGaN/GaN HEMT-based PAs, they always have self-heating effects which do degradate their electrical performace as well as reliability. In this talk, some new research progresses in electrothermal management and protection of LDMOSFET-, GaAs HBT-, and AlGaN/GaN HEMT-based RF PAs wil be addressed, and in particular including:

(1) Breakdown events and reliabilty concerns of RF PA & systems;  (2) Protection design of LDMOSFET-based RF PA for wireless base station application; (3) Electrothermal management of GaAs HBT-based RF PA in mobile phone; (4) Electrothermal protection design of ultra-wideband AlGaN/GaN-based RF PA.

Recently, various types of medical applications of antennas have widely been investigated and reported.  Typical recent medical applications include (1) Information/Wireless power transmission: Wearable or implantable vital data sensor/monitor; Wireless telemedicine/Mobile health system using IoT (Internet of Things); Wireless capsule endoscopy (2) Diagnosis: High intensity MRI (Magnetic Resonance Imaging); Microwave CT (Computed Tomography) for cancer detection; Wireless sleep monitor/ECG (electrocardiogram) monitor (3) Treatment: Thermal therapy (hyperthermia, ablation, etc); Wireless brain stimulator; Wireless DDD (drug delivery device); Surgical device (coagulation device, microwave knife, etc). In this presentation, some practical medical applications of microwave antennas which have been studied in our laboratory are introduced. Firstly, a wearable dual-mode antenna for vital data monitoring systems is presented.  A key technology for the antenna is body-centric wireless communications.  Secondly, an X-band antenna for a microwave sleep monitor is demonstrated with human-body phantom experiments.  A “dynamic” phantom played an important role for the study.  Thirdly, after a brief description of thermal therapy and microwave heating, a coaxial-slot antenna and an array applicator composed of several coaxial-slot antennas for minimally invasive microwave thermal therapy are overviewed.  A few results of actual clinical trials by use of coaxial-slot antennas are demonstrated from a technical point of view.  Finally, a few different types of surgical devices using high power microwave energy are introduced.  Heating characteristics of such microwave surgical devices are evaluated by numerical calculation as well as experiments using phantoms, meat and animals.

A study on body-centric wireless communications has become an active and attractive area of research because of their various applications such as e-healthcare, support systems for specialized occupations, monitoring systems for elderly and handicapped people, and so on.  For the purpose, the UHF band has been utilized in Europe and USA, however, the HF band is of great interest especially in Japan.  Hence, all of the prospective frequencies are in an extremely wide range, and an objective idea on how to select a right frequency band for individual applications is required.  As for the antennas, many types of wearable (on-body) and implantable (in-body) antennas have been reported. In this presentation, firstly, a brief history of body-centric wireless communications is reviewed.  Secondly, electric field distributions around the human body wearing a small top-loaded monopole antenna are numerically calculated and compared in a wide range of the HF to UHF bands.  Thirdly, received open voltages at receiving antennas which are equipped at several different points on the human body are numerically investigated.  Influence of nearby objects on received open voltages are also calculated and compared with frequency.  Then, a few examples of practical wearable antennas are introduced including a dual-mode wearable antenna which can be used at 10 MHz (on-body) as well as at 2.45 GHz (off-body) simultaneously.  Finally, some basic performances of miniaturized thin implantable antennas are numerically calculated in the UHF band.  Experimental validation by use of human phantoms is also demonstrated.

Radio frequency integrated circuits (RFIC) and mm-wave IC plays crucial role in the modern wireless communication systems in laptop, smart phones, tablet etc. Silicon based technologies with their low cost and high integrity prompt the widely adoption of the RF/mm-wave IC by consumer electronics. However, commercial silicon always faces issues of high substrate loss and metal loss especially for RF/mm-wave IC design caused by low resistivity silicon of ~10Ω/sq. We proposed new methodology of multiple-tank topology to cope with this loss issue. It is found that by using this approach, the performance of dedicated RF/mm-wave IC can be dramatically enhanced. It is also verified experimentally by silicon based IC such as VCO, frequency divider, Switch and other circuits with frequency up to 300GHz. Moreover, it is also used and verified in 60GHz Transceiver SOC. This talk is solicited to present the proposed method and implementation from the fundamental concept and analysis to the new integrated circuits and system verification.

In this presentation we will touch on two different topics under the general umbrella of Computational Electromagnetics, each of which is a relatively recent development in the area. The first of these is concerned with the application of a domain decomposition technique, called the Characteristic Basis Function Method (CBFM), to the problem of scattering by particles of complex shapes. The study was motivated by the fact that several Earth Science missions aimed at the observation of clouds, aerosol and precipitation by using active and passive sensors (e.g., NASA’s Global Precipitation Measurement, GPM program) require the development of a coherent electromagnetic (EM) scattering model to accurately calculate, at different frequencies, the absorption and scattering properties of inhomogeneous dielectric particles with complex geometries representing snowflakes of various sizes and shapes.
Next, we turn to the problem of investigating some multi-scale problems in the context of the Finite Difference Time Domain (FDTD) algorithm. Such a multi-scale problem often arises when we are dealing with objects comprised of a combination of large-scale and small-scale objects, e.g., a small on-body sensing antenna located close to a human body. The human body has relatively complex electromagnetic properties, and it is often analyzed by using the FDTD method which is capable of handling such inhomogeneous objects in a numerically efficient manner, especially on parallel processors, since it is an embarrassingly parallel algorithm. However, the FDTD is not well-suited for handling non-Cartesian geometries, especially wire-like strictures of thin radii and arbitrary orientations, since the FDTD requires a very fine mesh to model such geometries, at a heavy cost of both computational time and memory. To mitigate this problem, we introduce a hybrid approach--which handles the wire-like geometries or thin plates with arbitrary orientations that are also difficult to deal with in the context of the FDTD--by using a Method of Moments formulation, especially tailored to generate the scattered fields by the object using time-domain-compatible functions, which facilitate the hybridization of the MoM with the FDTD.

There is virtually no doubt in our minds that wireless broadband services are the key drivers behind the growth of the digital economy in the world we live in today. The demand for broadband services appears to be insatiable, no matter whether the users are on the road, at sea, in the air, or if they reside in remote and rural areas where broadband Wi-Fi is either unavailable or virtually inaccessible. To satisfy the demand for broadband services, various Ka-band communications satellites are currently being launched. Such networks can be formed by a combination of various platforms such as low earth orbit satellites, aircraft fleets, high altitude platforms (HAP) and ground stations.
It goes without saying that designing low-cost broadband in-the-sky networks that are expected to deliver data rates comparable to those provided by terrestrial services presents a gargantuan challenge. This presentation will discuss two types of millimeter wave antennas that are potential candidates as components for such networks, with a focus on low-cost designs. The first of these is a flat lens which can be manufactured by using a 3-D printer at a low cost. The second is a lightweight scannable phased array design which is also low-cost because it avoids the use of ferrite phase shifters, as well as alternate designs, that have both cost and weight issues.

This talk will present the latest work on microwave and mm-wave phased arrays and imaging systems at UCSD. The talk shows that one can build large phased arrays on a single chip for millimeter-wave applications, and these result in excellent uniformity between the elements and in wide beam scanning capabilities. One of the bottle necks is the use of high-efficiency antennas and these are solved either using a superstrate or an e-WLP process. Phased arrays and Imaging Arrays operating at 60 GHz, 90-110 GHz, and even 410 GHz will be presented. Also, links achieving Gbps links at 30 meters and 100 meters will be presented. It will be shown that SiGe and CMOS has changed the way we think about phased arrays and imaging systems.

The progress in the area of Computational Electromagnetics, together with the cost reduction and continuous increase of the computational speed and power of modern computers, have contributed to the development and broad diffusion of numerical software for the analysis and design of complex electromagnetic structures and systems. The geometry and the materials of these structures can nowadays be modeled by powerful pre-processor codes able to provide high order description of the problem to the electromagnetic “solver-software”. To take advantage of the high quality models available by using the modern pre-processors, several researchers have also developed in the last two decades high order basis functions for finite electromagnetic solver codes. This presentation is divided in two parts and is intended to provide an overview of the most recent developments obtained in this special area. After a brief overview of the fundamentals of finite methods, an in-depth coverage of higher order models for Moment Method and Finite Element Method applications is provided, thereby considering interpolatory and hierarchical higher order vector bases with a detailed discussion of the implementation problems and of the advantages provided by use of higher-order models.

The UWB radar sensor has received a great amount of attention lately from various industries due to its wide variety of practical applicability and future potential, including safety & security, customer relationship managements, positioning & tracking, healthcare, sports, energy savings, smart devices, smart vehicles, and so on, just to mention a few. In particular, as the Internet of Things has been widely spread, the role of the UWB radar sensor is getting more crucial.

This presentation gives an introduction to basic concepts, characteristics, and applications of the UWB radar sensor. Various signal processing and context-awareness computing algorithms will be discussed for each of UWB radar applications, such as presence detection for safety, intrusion detection for security, crowdedness measurement, moving direction recognition, counting people’s movement in pathways, 2D positioning and tracking, see thru walls, vital sign measurements, sleep monitoring, behavior monitoring of baby & elderly people, gesture recognition, and so on. Finally, recent research activities at Hanyang University on the UWB radar sensor will be introduced. Practical implementation issues as well as industrialization strategies of the UWB radar solutions will also be discussed.

There is virtually no doubt in our minds that wireless broadband services are the key drivers behind the growth of the digital economy in the world we live in today. The demand for broadband services appears to be insatiable, no matter whether the users are on the road, at sea, in the air, or if they reside in remote and rural areas where broadband Wi-Fi is either unavailable or virtually inaccessible. To satisfy the demand for broadband services, various Ka-band communications satellites are currently being launched. Such networks can be formed by a combination of various platforms such as low earth orbit satellites, aircraft fleets, high altitude platforms (HAP) and ground stations. At present, to overcome the inherent drawback of long latency in geo-stationary satellite systems, the momentum around low earth orbit (LEO) satellites is gathering pace as evidenced by the plans announced by WorldVU Satellites to launch a constellation of low-earth-orbit satellites. It goes without saying that designing broadband in-the-sky networks that are expected to deliver data rates comparable to those provided by terrestrial services presents a gargantuan challenge. To meet this challenge, it would be necessary to maximize the quality of wireless links between mounting platforms, to reduce the power consumption, and to design reconfigurable conformal antennas employing low complexity beamforming technology. Such a system would enable us to beam and capture the signal energy most efficiently in the desired direction in the face of changes in the orientations of the mounting platforms. This presentation will focus on the topic of reconfigurable antennas in the context of broadband in-the-sky network, and will review a number of options available to us today for designing such antennas to see which ones would be suitable for the broadband networks, keeping in mind that cost would be a big factor in determining which ones would win out as viable candidates.

Radio frequency identification (RFID) technology are being rapidly developed in recent years and the applications have been widely found in Internet of Things (IoT) such as service industries, distribution logistics, manufacturing companies, and product-flow systems. Antenna design for readers and tags is one of the key factors in RFID systems. The optimized tag and reader antenna design will greatly benefit to RFID systems with longer reading range, better detection accuracy, lower fabrication cost, and simple system configuration and implementation. This talk will start with a brief introduction to RFID systems which may be active, passive, or semi-active systems, and operate at LF, HF, UHF, or MW bands. Then the key considerations related to the antenna design for tags and readers will be addressed from system perspectives. After that, the advancement of RFID antenna designs by the team from Institute for Infocomm Research/Singapore National University of Singapore will highlight specific challenges for antennas in the HF near-field and UHF near/far-field systems. In particular, important engineering factors such as environmental effects vs. co-design methodology, size constraints, cost constraints, and UHF near-field reader antenna coverage will be presented with corresponding practical design cases.

An ubiquitous icon in this information era, radio frequency identification (RFID) is a natural extension of the bar-code system.  From industry point of view, what’s the future of RFID? Specially the adoption of RFID system in the retail business such as food chain, department stores, libraries…will be presented. How a IOT smart platform can help in the factory/manufacturing/ware house/institution/laboratory? When our mobile phone can be used as UHF RFID reader? What’s more? Let’s meet and share if you keen!.

Pattern reconfigurable antennas are gaining more and more attention, as they allow increased flexibility while using relatively small antenna. Currently most state-of-the-art pattern reconfigurable antennas rely on the use of some sort of switch integrated into antenna’s aperture – usually a pin diode, a varactor or MEMS switch, less often a piezoelectric element. This approach, although suitable for many applications, is difficult to implement for point-to-multipoint radio systems, such as LTE base stations or WLAN routers. This is mainly due to the fact, that a switching-reconfigurable antenna generates the same pattern throughout the whole bandwidth, without distinction between neighboring frequency channels. Even worse, the use of switches requires presence of often complex DC control lines and can decrease radiation efficiency. In this presentation, we would like to discuss recent advancements in pattern reconfigurable antennas, which does not use on any of the switching components in antenna’s aperture. The beam-steering relies on interference between multiple resonances within a single antenna volume. Such antennas use multiple ports, where digitally generated phase shift at each port is used to synthesize a patter – similarly to classical antenna arrays, however with substantially reduced size.

Mobile wireless communication has encountered an explosive growth in global scale over the past decades mainly driven by the massive use of smartphones, tablets. In order to meet the increasing demands, the revolutionary 5G networks with unprecedented data speeds are explored. In 5G application the demands of femtocells and picocells augmenting traditional macrocells base station which results in aggregation of non-contiguous of bandwidth across wide frequency range unleashes a great challenge and opportunity for novel multiband filter design. A new type of multi-band filter using hybrid polynomials filtering function is introduced. This is the first multiband low pass prototype network proposed which allows classical ladder synthesis and frequency transformation for the construction of multiband bandpass filter. It is also highly desirable to have a single bandstop filter with multiband rejection in order to address the dense utilization of 5G mobile broadband networks which are very likely suffering from multi-channel interferences. A new dual-band bandstop filter based on lossy reflection mode topology is introduced where the conventional design techniques had concentrated only on single band bandstop response due to the lack of multiband low pass prototype and frequency transformation technique.

In this seminar speaker will review ongoing experimental and theoretical efforts to explore the plasmonic response in metallic nanoparticles, where nanometric dimensions are expected to promote a nonlocal plasmonic response beyond that of the usual classical electrodynamics. Speaker will briefly review efforts to make semi-classical hydrodynamic extensions, as well as our most recent developments beyond these simplified models. Speaker will also address their most recent singleparticle EELS observations of high-order modes in silver nanoparticles. Speaker will then turn applications of nanoplasmonic systems, where localized plasmon resonances are used to facilitate broad range of plasmonic colours with applications in decoration of plastic surfaces and with novel opportunities to laser-post processing and printing of colours with subwavelength resolution.

The term "phased array" comes from the time-harmonic/steady state analysis of antenna arrays. These arrays use phase shifters to electronically steer the main beam. Phase shifters cause beam squint and pulse dispersion for wideband signals, so time delay units are needed to correct these errors. Adaptive and reconfigurable arrays also have time-dependent responses. In addition, time-dependent spurious signals arise due to nonlinearities in amplifiers. This talk presents several time varying issues related to antenna arrays that should not be modeled by the time-harmonic representation of an array. Future antenna arrays will be wideband and time-varying, so antenna arrays will have to be designed in the time domain.

A procedure is described for designing printed antennas that are partitioned into short segments and interconnected by lumped reactances. The procedure enables controlling the input impedance match and the radiation pattern. The design starts from the multiport impedance matrix generated by an electromagnetic simulation software. The analysis of the antenna equivalent circuit, based on that impedance matrix, provides the expression for the input impedance and also an approximate expression for the directivity of antenna. The values of individual reactive elements are then obtained by an optimization which does not require further use of the electromagnetic simulation software. Examples of square and circular half loop antennas designed for UAV or GPS communications will be presented.

Adaptive and reconfigurable antennas improve the reception of desired signals by changing their performance characteristics. Adaptive arrays automatically sense the presence of interference and suppress them while simultaneously enhancing desired signal reception without prior knowledge of the signal/interference environment. They use signal processing/numerical methods to change element weights. Reconfigurable antennas change the physical properties of an antenna in order to modify the frequency band, polarization, etc. This talk presents some non-digital beamforming approaches to adaptive nulling in addition to some new approaches to reconfigurable arrays.

Small antenna designs completed between 2010~2015 by Feng Chia University (FCU Antenna Group) will be fully presented, which includes the design topics such as (i) Array antenna for WiMAX, and WLAN with polarization diversity, (ii) Slot antenna for UWB, WLAN/WiMAX, (iii) RFID antenna for tag and reader applications, and (iv) WLAN antenna for Laptop applications. Future antenna design challenges will also be discussed in this presentation. Designs such as reconfigurable (frequency/polarization/beam-steering) antenna, long reading range CP tag, small RFID tag and full-metal cover laptop antennas etc. will also be discussed, and their limitation/problems encountered by the FCU Antenna Group will be disclosed in the presentation.

In this seminar, different CEM/MP methods will be introduced and implemented for studying on various multiscale/heterogeneous structures, from electrically large warship to RF power amplifier (PA), 2-D material-based metasurfaces/frequency selective surfaces (FSS), new generation memory and solar cells, with their capabilities, challenges and opportunities demonstrated by both numerical and experimental ways.

The time domain FEM is ideal for efficient simulation of ultra-wideband (UWB) antennas. On the other hand, it is necessary to consider the stability of implicit time domain finite element methods. In previously work, engineers and mathematicians have chosen backward Euler, Newmark method, etc. This talk focused on the Routh-Hurwitz Stability Criterion for stability analysis of implicit time domain finite element methods.