In this paper, we demonstrate the feasibility of ink-jet printed loop slot antenna fed by tri-plate line with nano particle silver ink. The fabrication process of ink-jet printing is easy to be printed by home ink-jet printer at lower cost. The antenna element consists of a loop slot, a parasitic patch and a feeding probe with stub. The antenna components are printed on paper based substrates with nano particle silver ink. This antenna has wide band characteristic that can cover more than 27% of fractional bandwidth with a VSWR less than 1.5 and a high isolation between dual-polarization feeding ports of more than 20 dB. This paper presents a design approach of this proposed antenna and the antenna characteristics.
This paper presents resonant elements for polarization conversion reflectarray. These elements have reflection-phase difference between the V-pol. and the H-pol. is about 90° range more than the fractional bandwidth 10% (axial ratio < 1.5) and the reflection phase characteristics are almost linear phase curves for the wide frequency range. To verify usefulness of the proposed elements, an offset-feed reflectarray constructed by them in the Ku-band is designed, and also the polarization property of the radiation pattern is investigated numerically and experimentally.
When local meteorological agencies advise an emergency alert, ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) television broadcasters would send a special signal to wake up the receivers. There are two ways of waking up: “Emergency Warning System (EWS)” that advises tsunami and earthquake disasters, and “Earthquake Early Warning (EEW)” that advises significant earthquake disasters. For detecting EWS wake-up indications, the use of the parity has been proposed. The method assumed the broadcasters do not change the message except for the wake-up indication. Because we cannot apply the method to an EEW wake-up indication detection, this letter proposes a method for EEW.
Although 60 GHz millimeter wave (mm-Wave) systems employing OFDM can provide multi-Gbps data rate, the high level of phase noise (PN) of the mm-Wave transceivers induces inter-carrier interference (ICI) that degrades the performance of the OFDM systems. In the conventional method, the effects of PN can be well compensated by the iterative receiver processing; however, it has high complexity. In the previous work, we proposed a simple frequency domain ICI compensation, that linearly combines the channel equalized receive signals; however, it needs PN-robust channel estimation methods. In this paper we evaluate the proposed scheme with considering the channel estimation, and propose a PN-robust channel estimation method.
Exploiting perceptual-based weighting can improve the reconstruction quality for compressed video sensing (CVS). Nevertheless, practical implementation of the compressed sensing (CS) requires quantizing the measurements. We propose a simplified sampling rate model for the perceptual CVS to achieve compromise between the number of measurements and the quantization bit-depth, which are the main contributing factors in the CS rate-distortion (RD) performance. The proposed model can achieve near optimal RD-performance obtained through exhaustive simulations. In addition, simulation results show that the quantized perceptual CVS achieves remarkable RD-performance gain, with lower sampling rate, compared to applying the quantization model on the standard CS.
Wideband Non-Contiguous OFDM (WNC-OFDM) technology can utilize small pieces of unused frequency bands for mobile communications. To use those bands, out-of-band leakage power (OOBLP) generates interference to adjacent radio systems. For this problem, the time windowing technique can suppress OOBLP, but the Bit Error Rate (BER) performance is degraded to achieve effective suppression of OOBLP. To manage both OOBLP suppression and BER performance, we propose Combined Time Windowing (CTW) technique where two different window time sections are used in the time windowing process. In this paper, we present the effectiveness of CTW in narrow frequency bandwidths and discuss an adaptive control scheme for CTW.
Pulse compression is used to improve range resolution and detectability of various radar systems. A multiple-input multiple-output (MIMO) radar is required to transmit an orthogonal code set from a transmit-antenna element. However, the design of a code set with orthogonality as well as good pulse compression properties for a MIMO radar is a difficult problem. Although complementary codes have an ideal pulse compression property, they have no cross-orthogonality. In this paper, we propose two code construction schemes based on space–time coding using complementary codes. The number of code sets and transmit-antenna elements can be easily extended by the proposed construction schemes.
OFDM has great advantages such as high spectral efficiency and robustness against multipath fading. Recently, machine-to-machine (M2M) communications and Internet of Things (IoT) command considerable attention, and the OFDM has been added to a physical layer (PHY) modulation in IEEE802.15.4g standards for smart utility networks (SUN). In this letter, we propose a threshold decision method for maximal-ratio diversity combining in the QAM constellation rearrangement to provide high communication quality with limited hardware resources like in the SUN. It is confirmed that the proposed method can outperform the conventional one without constellation rearrangement at low computational complexity.