The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This study investigates the erosion condition of irrigation earth structures and determines the measures for erosion protection in Cambodia paddy farming regions. Most irrigation facilities are earth structures (embankment), and due to heavy rainfalls and high erodible soils used for construction of embankments, the occurrence of erosion has increased in irrigation systems. Two irrigation sites: Thomney...
This paper clarifies the effects of configuration of a MIMO base station antenna on the channel capacity in line-of-sight street cell environment. It is shown that the optimum beam width in the horizontal plane depends on the road width and the distance from the base station. Moreover, it is also shown that the channel capacity decrease as the service area becomes wider.
This paper describes a design method of a metasurface that consists of two types FSS (Frequency Selective Surface) and the ground plane to realize broadband reflected wave reduction. The ideal filtering characteristics of one FSS is clarified when the other FSS is a patch type FSS. A loop and patch type FSS is proposed to realize the ideal filtering characteristics. Then, a meta-surface with reflected...
A low-profile and decoupling dipole antenna array is achieved by combining patch type meta-surface with proposed parasitic cells. Based on the moment method analysis results, it is clarified that proposed parasitic cells can suppress mutual coupling of dipole antennas without additional impedance. In addition, the maximum decoupling effect of 13.3 dB is achieved.
This paper describes the optimum directivity of a low base station antenna for street microcell. In order to simulate the propagation characteristics, the ray tracing technique is applied for street microcell. And, the channel capacity is evaluated for optimizing the antenna directivity. It is clarified by the simulation results that the optimum beam tilt angle and the beam width in the vertical plane...
This paper proposes a meta-surface for orthogonal polarization conversion, and describes the design method of the meta-surface by using a patch type unit cell. It is clarified by the simulation results that the patch type meta-surface can realize orthogonal polarization conversion in the frequency bandwidth of 46.8%.
Recentry, interference of artificial noises from electrical power transfer becomes large and deterioration of sound quality of AM radio is worried. The authors proposed a noise suppression system for AM radio using quadrature demodulation and PI algorithm. It is expected that the noise suppression effect is reduced when the system has a synchronization error. In this paper, an effect of synchronization...
This paper proposes the spatial filter with multilayered FSS(Frequency Selective Surface) for wideband orthogonal polarization conversion such as converting vertical polarization to horizontal polarization. It is indicated that FSS with LPF(Low-Pass Filter) and HPF(High-Pass Filter) in orthogonal direction realizes wideband orthogonal polarization conversion. Furthermore, it is shown that the optimal...
A near field object position estimation method using hyperbolas have been proposed by the authors. This paper clarifies performances of the proposed method by a geometrical optics approximation analysis. In addition, effectiveness of the proposed method is shown by comparison of the approximated analysis results and electromagnetic analysis results.
In indoor position estimation, it is necessary to consider multiple objects. This paper proposes a successive position estimation method for multiple objects using UWB signal. Further, estimation accuracy of the proposed method is evaluated. It is shown that the number of objects is increased, the estimation accuracy is reduced. It is also shown that the estimation accuracy less than 0.05m is obtained...
This paper focuses on an AMC (Artificial Magnetic Conductor) composed of a FSS (Frequency Selective Surface) and the ground plane, and describes the design method of the unit cell of the AMC to realize PMC (Perfect Magnetic Conductor). The FSS that consists of a patch type FSS and a medium is proposed to realize broadband PMC characteristics. A frequency characteristics of the relative permittivity...
This paper proposes the horizontally polarized omni-directional antenna with a cylindrical frequency selective surface (FSS). The FSS features the orthogonal polarization conversion function. Therefore, the vertically polarized wave radiated from a dipole antenna is converted to the horizontally polarized transmitted one. The simulation results by using the FDTD and the MoM show that this antenna...
Recently, electromagnetic interference in AM radio receivers associated with noise generated from the power control unit (DC-DC converters/inverters) and other power electronics devices, such as an electric power steering (EPS) control modules, in hybrid vehicles (HVs) has become a serious problem. In order to address this problem, most noise suppression methods use either noise filters (for noise...
This paper proposes the spatial filter with FSS(Frequency Selective Surface) for orthogonal polarization conversion such as converting the vertical polarization to horizontal polarization. It is found that multilayered loop-slot type FSS having band-pass filter characteristics realize orthogonal polarization conversion. Furthermore, it is shown that the optimal number of layers of the FSS is three,...
This paper describes a configuration of meta-surface with frequency selective surface (FSS) for wideband polarization conversion. Requirements of the FSS for realizing wideband polarization conversion function are clarified. To satisfy the requirements, a configuration of meta-surface by using low-pass and band-rejection spatial filter is proposed. As the result, about 50% of relative bandwidth of...
In this paper, a novel communication system for limited area communication is proposed. In the proposed system, sum pattern and differential pattern is used. A main beam of the sum pattern is directed to the direction of the desired user and signal for communication is transmitted using the main beam. On the other hand, a null of the differential pattern is also directed to the desired user and a...
This paper proposes the variable reflection angle meta-surface composed of the double layered FSS (Frequency Selective Surface) and the ground. The meta-surface can steer the reflection direction of the incident wave by shifting the lower FSS. It is clarified that the gradient of the reflection phase in the reflection direction steering plane (x-z plane) are changed by the shift amount of lower FSS...
This paper proposes a variable reflection angle meta-surface using double layered FSS (Frequency Selective Surface) for orthogonally polarized waves which can change the scattering pattern easily by shifting one layer. The reflection angle within range of about −20 deg. to −5 deg. is obtained in case of orthogonally polarized waves.
A meta-surface can reflect the incident wave with arbitrary reflection coefficient. This paper proposes a novel meta-surface which has polarization conversion function. A linearly polarized (LP) incident wave can be converted to a circularly polarized (CP) reflected wave by using a rectangular patches and the ground plane. In addition, the relationship between the frequency bandwidth and the structure...
In recent years, interference of artificial noises from electrical power transfer becomes large and deterioration of sound quality of AM radio is worried. In this paper, a noise suppression system using quadrature demodulation techniques is proposed to reduce the effect of the interference. The proposed system utilizes the fact that the in-phase signal from the demodulator includes both of AM signal...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.