In-band full duplex requires digital self-interference cancellations (SICs). However, digital SICs are significantly challenged due to radio-frequency (RF) impairments. We have proposed several designs and analyses of digital SIC based on parallel Hammerstein models addressing RF impairments. Our proposed designs and analyses use orthogonal frequency division multiplexing in the Hammerstein SICs. Moreover, we have developed a testbed to evaluate the Hammerstein and our proposed SICs. Our experimental results showed that the self-interference cancellation ratio was 48.1 dB for one of the Hammerstein SICs. This paper reveals that our canceler designs and theoretical analyses can improve the Hammerstein SICs.

In recent years, checking sleep quality has become essential from a healthcare perspective. In this paper, we propose a respiratory rate (RR) monitoring system that can be used in the bedroom without wearing any sensor devices directly. To develop the system, passive radio-frequency identification (RFID) tags are introduced and attached to a blanket, instead of attaching them to the human body. The received signal strength indicator (RSSI) and phase values of the passive RFID tags are continuously obtained using an RFID reader through antennas located at the bedside. The RSSI and phase values change depending on the respiration of the person wearing the blanket. Thus, we can estimate the RR using these values. After providing an overview of the proposed system, the RR estimation flow is explained in detail. The processing flow includes noise elimination and irregular breathing period estimation methods. The evaluation demonstrates that the proposed system can estimate the RR and respiratory status without considering the user's body posture, body type, gender, or change in the RR.

In this study we propose a manufacturing control framework based on radio-frequency identification (RFID) technology and a distributed information system to construct a mass-customization production process in a loosely coupled shop-floor control environment. On the basis of this framework, we developed RFID middleware and an integrated information system for tracking and controlling the manufacturing process flow. A bicycle manufacturer was used to demonstrate the prototype system. The findings of this study were that the proposed framework can improve the visibility and traceability of the manufacturing process as well as enhance process quality control and real-time production pedigree access. Using this framework, an enterprise can easily integrate an RFID-based system into its manufacturing environment to facilitate mass customization and a just-in-time production model.

With the smaller layout area and parasitic capacitance under the same electrostatic discharge (ESD) robustness, silicon-controlled rectifier (SCR) has been used as an effective on-chip ESD protection device in radio-frequency (RF) IC. In this paper, SCR's with the waffle layout structures are studied to minimize the parasitic capacitance and the variation of the parasitic capacitance within ultra-wide band (UWB) frequencies. With the reduced parasitic capacitance and capacitance variation, the degradation on UWB RF circuit performance can be minimized. Besides, the fast turn-on design on the low-capacitance SCR without increasing the I/O loading capacitance is investigated and applied to an UWB RF power amplifier (PA). The PA co-designed with SCR in the waffle layout structure has been fabricated. Before ESD stress, the RF performances of the ESD-protected PA are as well as that of the unprotected PA. After ESD stress, the unprotected PA is seriously degraded, whereas the ESD-protected PA still keeps the performances well.

We study radiated RF (radio-frequency) electromagnetic field immunity test system for wireless LAN system by using opened PW (Parallel Wired) cell, in which metal cover is removed. Leakage electric field at distance of 160 cm from the opened PW cell decreases until 30 dB, and then does not affect to operation of the AP (Access Point) composed of the wireless LAN system that communicates EUT (Equipment Under Test) installed in the PW cell. NSA (Normalized Site Attenuation) between EUT and AP changes only several dB by inserting the PW cell, and then it can be concluded that the effect of PW cell for radio wave property of wireless communication system is negligible small. In addition, we try to measure dependencies of impressing level of disturbance wave on a throughput of wireless LAN systems IEEE802.11b and IEEE802.11g. As a result, it is confirmed that the radiated RF electromagnetic field immunity test system for wireless LAN system can be composed by using the opened PW cell without affecting from impressing disturbance wave.

The subject is the horizontal coil's temperature rise in DY for high frequency by being unavoidable for the tendency of more information on display monitor equipments. Writers made the temperature-balance model from a point of view that this temperature rise is coming from the heat rise and the conductivity, and we expressed the temperature rise of DY by using amount of the heat rise and conductivity characteristics of each element. Also, we indicated the method to decide about the selection of the wire size of coils, the section area and deflection sensitivity, with regard to reducing the temperature rise. We confirmed the effect of the temperature rise reduction by about 9 on products, under the condition of 64 kHz horizontal frequency.

An experimental SAR (Specific Absorption Rate) estimation system based upon the thermograph method using a thermograph camera and newly developed homogeneous dry-phantom human models are presented. Experiments are conducted using this system and UHF fields to obtain SAR distributions in the human head irradiated by hand-held portable radios. Experiment results show that the estimated peak SAR's due to the radiation waves from radios of 1W transmitting power are lower than 2W/kg and so conform to the recommendations of the radio-frequency radiation safety guidelines. The developed system enables the surface SAR distributions on the phantom model to be precisely estimated; a function not available with the original system. System parameters required for providing precise estimations are discussed first, and then experiments are conducted to estimate SAR's in the human head exposed to a UHF hand-held portable radio's near field. Finally, estimated data are examined from the viewpoint of radio-frequency exposure safety guidelines.