The complex permittivity normal to substrates can be measured by the balanced-type circular disk resonator method at microwave and millimeter wave frequencies. However, in the case of substrates for medium-loss materials with a dielectric loss tangent of about 10^-2 and thickness of 1mm or less, the unloaded Q of the resonator decreases to about several tens, causing distortion in the resonance response. Therefore, it becomes difficult to measure the complex permittivity accurately. In this paper, we propose a polytetrafluoroethylene (PTFE) sheet loaded balanced-type circular disk resonator. By loading PTFE sheet, the distance between the conductors of the resonator is widened, and in addition, the concentration of electric field energy into the dielectric sample is weakened adequately, so that the unloaded Q of the resonator increases. The availability of this method is verified by measuring the frequency dependence of the complex permittivity of the FR4 substrate from 5 to 30 GHz.

Malignant neoplasms (Cancers) are accounts for 30% of the total deaths in Japan. And the number of the death due to the lung cancer is the most both men and women. It is being removed by video assisted thoracic surgery now. However, the position of the lung cancer is estimated visually in the surgery, so the surgery needs a lot of time and the advance techniques. In this paper, the resonant-types of electrodes have been proposed in order to improve the accuracy of the lung cancer estimation; decrease the surgery burden; shorten the surgery time. The possibility of the lung cancer estimation was confirmed by using our proposed methods. As the further works, we will miniaturize the structure and improve the estimation sensibility.

An 8 Gbps high-speed relay MMIC for an Automated Test Equipment (ATE) using a gallium nitride is developed and evaluated. Metal-Insulator-Semiconductor structure with a tantalum oxynitride is employed to reduce a leakage current for ATE applications. The fabricated MMIC shows 0.3 nA of the leakage current, 12 GHz of a -3 dB bandwidth, and excellent eye-opening of 8 Gbps signals with a 18-leads QFN package. The MMIC has 2.0×2.4 mm of package size and achieves higher channel density than an existing photo relay generally applied in ATE.

In this paper, complex impedance locus of the triangular-shaped electrodes with immobilized λDNAs were calculated by numerical simulations. Compare with the impedance of the electrodes with immobilized λDNAs, its impedance after deoxyribonuclease (DNase) treatment were increased by about 3 times or more. The DNA molecules can be applied to electrical detection of DNase which is a candidate biomarker for acute myocardial infarction.

Recently, since many wireless terminals become to be used, the introduction of small cells is considered to increase data throughput. This paper proposes allocation of indoor base stations for multiple-carrier and multiple-communication systems. The base station antenna allocation is determined by using a genetic algorithm and electromagnetic simulation based on the ray-tracing method. Evaluation of each gene, in addition to the area coverage according to the communication quality index, including the wiring cost, such as cable length and coupler number of the wiring. The novel genetic operation enables to create a gene that meets the conditions of communication areas in the building. We confirmed that how our genetic operation is effective in the case of WCDMA (Wideband Code Division Multiple Access) /CDMA (Code Division Multiple Access) 2000 1x, LTE (Long Term Evolution), and WiMAX (Worldwide Interoperability for Microwave Access).

This paper proposes a new design procedure and structure of a wideband dielectric phase shifter for mobile base stations. Phase shifters are used to tilt the main beam direction of a base station antenna array in the elevation angle. Recently, to enhance communication capacity for accommodating increasing data traffics due to the increased number of smartphones and tablets, multiple frequency bands were added in mobile communication systems. Therefore, wideband phase shifters are demanded. The proposed phase shifter composes two arrayed M-shaped dielectrics to introduce a periodic dielectric structure. This structure enhances a frequency bandwidth by creating a lower resonant frequency. Because resonant frequencies and bandwidth of the proposed phase shifter can be adjusted by using a design equation of the M-shaped dielectric phase shifter, the proposed method can simplify a wideband phase shifter design. Frequency responses of voltage standing wave ratio (VSWR) less than 1.2 were theoretically analyzed, satisfying a frequency range from 1.4 to 2.2GHz. This range covers 1.5, 1.7, and 2.2GHz band, where this phase shifter is designed to obtain a phase shift of 60 deg. at the center frequency, 1.8GHz. A prototype of the proposed phase shifter was fabricated to validate the frequency responses of VSWR less than 1.2. The experimental result confirmed that the proposed phase shifter can approximately realize the objective bandwidth.

The number of IoT service provider is increasing. Such IoT services require different-type wireless communication systems from conventional systems such as WiFi or LTE·5G, which can transmit large amount of data. Those wireless systems have a capability of low-power and long-distance communication by transmitting small amount of data with low duty cycle. There is, however, a challenging issue in radio propagations since IoT devices are located in harsh radio environments, especially for social infrastructure IoT service. In this paper, we analyze radio propagation from manholes which are used for social infrastructure such as gas, water supply and power grid to discuss solutions for long-distance and low-power wireless communications for social infrastructure.

A novel ray-tracing method in which mobile bodies are represented by dielectric cylinders to evaluate dynamic electromagnetic field of wireless communication service areas is proposed. The proposed method uses novel scattering rays which are created by induced current on the surfaces of the cylinders and radiated from the center axes of them to be useful for calculation of electromagnetic field in the shadow regions behind them. The ray-tracing method using these novel rays achieve more accurate evaluation of the field in the shadow region with less calculation time than that using conventional diffraction waves.

The wireless system selecting polarization on which information signal is transferred to achieve better communication quality is proposed. The system uses a radio device that consists of a micro controller, two RF chips, a 90 degree hybrid coupler, and two perpendicular antennas to generate the rotating polarization wave where these RF chips are operated at the different local frequencies. Since the proposed system is compatibly operated with the conventional system that uses the same RF chip, it achieves a better quality by selecting both transmitting and receiving polarizations than the conventional system even if a mobile object is passing the radio devices or carrying it.

We propose a payment system by block chain and IC card readers for local transport systems in this paper. So far, IC card payment for transport system emerged in urban cities in Japan. However, the expansion of IC card in local city is not yet successful. We speculate that the reason is that the reader is expensive, and the investment is a burden. for small business companies. Therefore, in order to realize an inexpensive card reader, we introduced a blockchain as a payment system to move the value recorded in the card side to the cloud side. In this paper, we show the outline of the system and that it is easy to apply this system to inter-company payments(B2B) as well as B2C, and propose the concept of card reader roaming to share a blockchain by multiple companies.

It is known that the life of a Lithium-ion (Li-ion) battery is affected by charge/discharge rates, temperature, and depth of discharge (DoD). This paper investigates the effect of temperature and DoD on a 18650 Li-Ion cell. An experiment is set up to analyze the impact of temperature and DoD on the performance of Li-Ion cells. The test temperatures of 25°C and 35°C, whereas DoD of 80% and 90%, are considered for the analysis. The paper aims at studying the effects of these parameters on capacity degradation, discharge energy efficiency, and coulombic efficiency over the cell's lifetime.

Effective conductivity of a conductor applicable for an additive manufacturing (AM) might be quite low due to fabrication processes that are coating, plating and inkjet printing, compared as a copper bulk. Therefore, accurate evaluation methods for a low conductivity material are required to improve material characteristic in the frequency band for 5G wireless networks. In this report, we verified usefulness of the two dielectric rod resonator method as a low conductivity evaluation method based on measured results of several conductive materials for AM technology.

In this letter, we propose a simple MQTT-based IoT prototype system consisting only of open source and general-purpose electronic components. The Message Queueing Telemetry Transport (MQTT) protocol is attracting attention as a protocol for IoT. Although many results of data collection via MQTT have been reported, the actuation of IoT systems via MQTT has not been well reported. We demonstrate the actuation operation based on received messages and demonstrate the effectiveness of the proposed prototype system.

Recently, omnidirectional moving AMR (autonomous mobile robot) are researched. For some kind of transportation application, AMR is required to have a horizontality keeping ability by itself. A robot which ride on a sphere and moves omnidirectionally is already proposed and the robot can keep horizontality. But the robot must slightly tilt to an accelerating direction when start to move. We propose a robot with all direction moving ability and keep horizontality during acceleration and deacceleration. The proposed robot is composed of external unit and internal unit. Both unit have all direction moving ability by three omni wheels. External unit rides on a sphere and it maintains horizontality. On the other hand, internal unit moves inside the sphere and controls the moving direction and moving speed of the sphere. We compared the proposed robot, with external unit and internal unit, to a robot with only an external unit. By our experiment, it was evaluated that the proposed robot can keep much more horizontality. It is also indicated that the proposed robot can move with much higher acceleration, and can move on a slope with keeping horizontality.

This paper presents a method for filtering the change direction of nonstationary time series using the improvement type sine wave indicator. The sine wave indicator is a method for converting a time series into a sine curve and calculating where the current value is on the sine curve. However, this method has a problem that nonstationary time series in which a plurality of periodic functions and trend line are mixed cannot be analyzed. Therefore, after removing the high frequency noise from the analysis time series, it is decomposed into the intrinsic mode function for each frequency according to the empirical mode decomposition, and the sine wave indicator is applied to the decomposed time series. By evaluating the sine curve created by the sine wave indicator for the section where the influence of the trend component is small, the current change direction of the nonstationary time series could be filtered.