This paper studies the performance of the quantitative RF power variation in Radio-over-Fiber beam forming system utilizing a phased array-antenna integrating photo-diodes in downlink network for next generation millimeter wave band radio access. Firstly, we described details of fabrication of an integrated photonic array-antenna (IPA), where a 60GHz patch antenna 4×2 array and high-speed photo-diodes were integrated into a substrate. We evaluated RF transmission efficiency as an IPA system for Radio-over-Fiber (RoF)-based mobile front hall architecture with remote antenna beam forming capability. We clarified the characteristics of discrete and integrated devices such as an intensity modulator (IM), an optical fiber and the IPA and calculated RF power radiated from the IPA taking account of the measured data of the devices. Based on the experimental results on RF tone signal transmission by utilizing the IPA, attainable transmission distance of wireless communication by improvement and optimization of the used devices was discussed. We deduced that the antenna could output sufficient power when we consider that the cell size of the future mobile communication systems would be around 100 meters or smaller.

Coil-shaped structures are proposed to enhance sensitivity and spatial resolution for EMI near-field probe. This design yields a high sensitivity and a good spatial resolution to find the EMI source in near-field region. Both characteristics are crucial to diagnosis of emissions from electrical and electronic devices. The new design yields a superior sensitivity, which is in general 15 dB greater than conventional probes. This new probe helps practitioners to quickly and correctly locate noise emission source areas on printed circuit boards and devices. Two prototypes of different sizes were fabricated. The larger one provides a high sensitivity while the smaller one can pinpoint emission source locations. The new probe design also has an orientation invariance feature. Its noise response levels are similar for all probe directions. This characteristic can help reduced the probability at miss-detection since sensitivity is largely invariant to its orientation. Extensive measurements were performed to verify the operation mechanism and to assess probe characteristics. It suits well to the electromagnetic interference problem diagnosis.

This paper proposes fabrication process of a pyramidal electromagnetic (EM) absorber made by natural rubber. The advantage of this research is to generate value-added latex from Thai rubber and to reduce number of chemical absorber by using natural rubber based absorber. The proposed absorber in the research is mainly made from latex with carbon black filler. The proposed absorber is in the form of rubber foam which provides suitable characteristics to serve as an EM absorber. The results of this research are chemical formulas for fabrication of pyramidal rubber foam with carbon black filler. The fabrication cost is very low when compared to an available commercial absorber. The electrical properties of the proposed EM absorber are measured. Also the reflectivity is measured and compared well with a commercial EM absorber.

Hydrophobic DNA (H-DNA) nano-film was formed on a thin glass plate of 50μm thick working as a slab optical waveguide. Bromothymol blue (BTB) molecules were immobilized from aqueous solution with direct contacting to the H-DNA nano-film for 20 minutes. From changes in absorption spectra observed with slab optical wave guide (SOWG) during automated solution exchange (SE) processes for 100 times, it was found that about 95% of bromothymol blue (BTB) molecules was immobilized in the H-DNA nano-film with keeping their functionality of color change responsible to pH change in the solution.

With the rising importance of information security, the necessity of implementing better security measures in the physical layer as well as the upper layers is becoming increasing apparent. Given the development of more accurate and less expensive measurement devices, high-performance computers, and larger storage devices, the threat of advanced attacks at the physical level has expanded from the military and governmental spheres to commercial products. In this paper, we review the issue of information security degradation through electromagnetic (EM)-based compromising of security measures in the physical layer (i.e., EM information security). Owing to the invisibility of EM radiation, such attacks can be serious threats. We first introduce the mechanism of information leakage through EM radiation and interference and then present possible countermeasures. Finally, we explain the latest research and standardization trends related to EM information security.

This paper presents various Iterative Progressive Numerical Methods (IPNMs) for the computation of electromagnetic (EM) wave scattering from many objects. We previously modified the original IPNM from the standpoint of the classical and the IDR-based linear iterative solvers. We demonstrate the performance of the IDR(s)-based IPNMs through some numerical examples of EM wave scattering from regularly placed 27 perfectly electric conducting spheres.

In this study, transverse magnetic electromagnetic plane wave scatterings by rectangular cylinders have been analyzed by a high frequency asymptotic method. Scattering field can be generated by the equivalent electric and magnetic currents which are obtained approximately from the geometrical optics (GO) fields. Our formulation is found to be exactly the same with the physical optics (PO) for the conducting cylinders, and it can also be applicable for dielectric cylinders. Numerical calculations are made to compare the results with those by other methods, such as the geometrical theory of diffraction (GTD) and HFSS simulation. A good agreement has been observed to confirm the validity of our method.

This paper describes the equivalent-circuit model of a metamaterial composed of conducting spheres and wires. This model involves electromagnetic coupling between the conductors, with retardation. The lumped-parameter equivalent circuit, which imports retardation to the electromagnetic coupling, is developed in this paper from Maxwell's equation. Using the equivalent-circuit model, we clarify the relationship between the retardation and radiation loss; we theoretically demonstrate that the electromagnetic retardation in the near-field represents the radiation loss of the meta-atom in the far-field. Furthermore, this paper focuses on the retarded electromagnetic coupling between two meta-atoms; we estimate the changes in the resonant frequencies and the losses due to the distance between the two coupled meta-atoms. It is established that the dependence characteristics are significantly affected by electromagnetic retardation.

Reverberation chambers (RCs) are used widely in the electromagnetic measurement area. An RC is designed to have a long reverberation time, generate numerous modes, and provide good field uniformity within the chamber. The purpose of this paper is to describe the design process and measurement of the KRISS Reverberation Chamber (KRC). KRC models with 4.5m × 3.4m × 2.8m dimensions are simulated by 3D numerical simulation software. The field uniformity and correlation coefficient are then analyzed at 200MHz to obtain the optimized model. The simulation results show good performance in terms of field uniformity and are confirmed by measurement from 200MHz to 1GHz. The lowest usable frequency (LUF) of KRC was confirmed by field uniformity to be 200MHz. However, the stirrer correlation coefficient results show good performance above 300MHz.

Recently, IoT compatible products have been popular, and various kinds of things are IoT compliant products. In these devices, cryptosystems and authentication are not treated properly, and security measures for IoT devices are not sufficient. Requirements of authentication for IoT devices are power saving and one-to-many communication. In this paper, we propose a zero-knowledge identification scheme using LDPC codes. In the proposed scheme, the zero-knowledge identification scheme that relies on the binary syndrome decoding problem is improved and the computational cost of identification is reduced by using the sparse parity-check matrix of the LDPC codes. In addition, the security level, computational cost and safety of the proposed scheme are discussed in detail.

In this paper, a proof-of-concept sensor platform for an all-in-one wireless bio sensor chip was developed and evaluated. An on-chip battery, an on-chip electrochromic display (ECD), a micro processor, a voltage converter and analog switches were implemented on a printed circuit board. Instead of bio-sensor, a temperature sensor was used to evaluate the functionality of the platform. The platform successfully worked in an electrolyte and the encoded measurement result was displayed on the ECD. The displayed data was captured by a CMOS digital camera and the measured data could be successfully decoded by a computer program.

This paper discusses VDT syndrome from the point of view of the viewing distance between a computer screen and user's eyes. This paper conducts a series of experiments to show an impact of the viewing distance on task performance. In the experiments, two different viewing distances of 50cm and 350cm with the same viewing angle of 30degrees are taken into consideration. The results show that the long viewing distance enables people to manipulate the mouse more slowly, more correctly and more precisely than the short.

This paper presents a water leakage monitoring system that gathers acoustic data of water pipes using wireless communication technology and identifies the sound of water leakage using machine leaning technology. To collect acoustic data effectively, this system combines three types of data-collection methods: drive-by, walk-by, and static. To design this system, it is important to ascertain the wireless communication distance that can be achieved with sensors installed in a basement. This paper also reports on radio propagation from underground manholes made from reinforced concrete and resin concrete in residential and commercial areas using the 920 MHz band. We reveal that it is possible to design a practical system that uses radio communication from underground sensors.

Electrical contacts are separated at constant speed and break arcs are generated in nitrogen or air in a 200V-450VDC/10A resistive circuit. The break arcs are extinguished by magnetic blow-out. Arc duration for the silver and copper contact pairs is investigated for each supply voltage. Following results are shown. The arc duration for Cu contacts in nitrogen is the shortest. For Cu contacts, the arc dwell time in air was considerably longer than that of nitrogen. For Ag contacts, the arc duration in nitrogen was almost the same as that in air.

An equivalent circuit of Yee's cells is proposed for mixed electromagnetic and circuit simulations. Using the equivalent circuit, a mixed electromagnetic and circuit simulator can be developed, in which the electromagnetic field and circuit responses are simultaneously analyzed. Representing the electromagnetic system as a circuit, active and passive device models in a circuit simulator can be used for the mixed simulations without any modifications. Hence, the propose method is very useful for designing various electronic systems. To evaluate the mixed simulations with the equivalent circuit, two implementations with shared or distributed memory computer system are presented. In the numerical examples, we evaluate the performances of the prototype simulators to demonstrate the effectiveness.

In this study, a theory for estimating the dielectric properties for unknown materials from three reference materials without using a short condition was developed. Specifically, the relationships linking the S parameter, electrostatic capacity, the measurement instrument and the jig were determined for four equivalent circuits with three reference materials and an unknown material inserted into the jig. An equation for estimation of complex permittivity from three reference materials without short termination was thus derived. The formula's accuracy was then numerically verified for cases in which values indicating the dielectric properties of the reference materials and the actual material differed significantly, thereby verifying the effectiveness of the proposed method. Next, it was also found that dielectric constant could be correctly determined even when the observation plane was moved to the SOL calibration plane on the generator side. The dielectric properties of various liquids in the 0.50, 1.0 and 2.5 GHz bands as measured using the proposed method were then compared with corresponding conventional-method values. Finally, the validity of the proposed method was also indicated by measurement values showing the frequency characteristics of dielectric properties at frequencies ranging from 0.50 to 3.0 GHz.

In this paper, dependency of transmission loss of shielded-flexible printed circuits (FPC) for differential-signaling on thickness of conductive shield is studied by numerical modeling based on an equivalent circuit model compared with the experimental results. Especially, the transmission loss due to the thin conductive shield is focused. The insufficient shielding performance for near magnetic field decreases the resistance due to the thin conductive shield. It is shown that the resistance due to the thin conductive shield at lower frequencies is smaller than that in the “thick conductive shield” case.

In this paper we report the convergence acceleration effect of the extended node patch preconditioner for the iterative full-wave electromagnetic finite element method with more than ten million degrees of freedom. The preconditioner, which is categorized into the multiplicative Schwarz scheme, effectively works with conventional numerical iterative matrix solving methods on a parallel computer. We examined the convergence properties of the preconditioner combined with the COCG, COCR and GMRES algorithms for the analysis domain encompassed by absorbing boundary conditions (ABC) such as perfectly matched layers (PML). In those analyses the properties of the convergence are investigated numerically by sweeping frequency range and the number of PMLs. Memory-efficient nature of the preconditioner is numerically confirmed through the experiments and upper bounds of the required memory size are theoretically proved. Finally it is demonstrated that this extended node patch preconditioner with GMRES algorithm works well with the problems up to one hundred million degrees of freedom.

The growth mechanisms of three-dimensionally (3D) faceted InGaN quantum wells (QWs) on (=1=12=2) GaN substrates are discussed. The structure is composed of (=1=12=2), {=110=1}, and {=1100} planes, and the cross sectional shape is similar to that of 3D QWs on (0001). However, the 3D QWs on (=1=12=2) and (0001) show quite different inter-facet variation of In compositions. To clarify this observation, the local thicknesses of constituent InN and GaN on the 3D GaN are fitted with a formula derived from the diffusion equation. It is suggested that the difference in the In incorporation efficiency of each crystallographic plane strongly affects the surface In adatom migration.

Location information is meaningful information for future ITS (Intelligent Transport Systems) world. Especially, the accuracy of the information is required because the accuracy decides the quality of ITS services. For realization of high precision positioning, Kinematic positioning technique has been attracting attention. The Kinematic positioning requires the configuration of many positioning parameters. However, the configuration is difficult because optimal parameter differs according to user's environment. In this paper, we will propose an estimation method of optimal parameter according to the environment. Further, we will propose an elimination method of unreliable positioning results. Hereby, we can acquire extensively only the reliable positioning results. By using the actual vehicle traveling data, the ability and the applicable range of the proposed method will be shown. The result will show that our proposed method improves the acquision rate of reliable positioning results and mitigates the acquision rate of the unreliable positioning results.