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In this paper, a lamination of a magnetic sheet and a copper sheet is proposed to obtain wideband shielding effect from kHz to MHz bands. The requirement of the laminated magnetic sheet was discussed. A cap type shield case applying the laminated sheet 53 μm thick was fabricated and its shielding effect was measured. The higher shielding effect was obtained using the proposed sheet in the frequency...
A conducted disturbance measuring apparatus using two parallel transverse electromagnetic (TEM) cells was developed for improving the balance of the conventional apparatus using one TEM cell. However, the balance of the developed apparatus has not been evaluated. In this study, its longitudinal conversion loss (LCL) was measured. As a result, the LCL of the apparatus was obtained as more than 30 dB...
An active frequency selective surface (FSS) which is switched as a radar absorber and transmission surface using pin diodes at the same frequency is proposed. The diodes are arranged on the both sides of the active FSS. The active FSS performs as a radar absorber and transmission surface with OFF- and ON-state diodes. The active FSS is fabricated and demonstrated. The measured reflection and transmission...
Antenna design for radar cross section (RCS) reduction using reradiation interference cancellation was demonstrated. The RCS of a dipole antenna with a reflector was reduced using the interference cancellation between scattering and reradiation. The length of the feed line and element of the dipole antenna was designed for low return loss and RCS at 9 GHz. The optimized lengths of them are needed...
In this paper a double loop antenna for a mobile satellite reception with tilted beam is proposed. The double loop antenna is fed by a modified single strip line. The currents of each element are adjusted by the structure of the strip line. The antenna is designed and measured. As a result, the gain of 4.6 dBi at 27 degree tilted direction and 10 dB bandwidth of more than 500 MHz at the operational...
A switchable reflector which can switch reflection level using pin diodes for the vertical polarization and absorb for the horizontal polarization was proposed. The vertical polarized reflection coefficient was switched −29 dB with OFF-state diodes and −0.5 dB with ON-state diodes, and horizontal polarized one was less than −15 dB at 9 GHz. The reflector with ON-state diodes was applied to an antenna...
A switchable reflector using pin diodes for the radar cross section (RCS) reduction of an antenna reflector was proposed. The reflection coefficient of the proposed reflector was able to be switched between less than −20 dB with OFF-state diodes and more than −0.8 dB with ON-state diodes around 9 GHz. The proposed reflector with ON-state diodes was applied to the reflector of a dipole array antenna...
A switchable reflector using pin diodes for the radar cross section (RCS) reduction of an antenna reflector was proposed. The reflection coefficient of the proposed reflector was able to be switched between less than −25 dB with OFF-state diodes and more than −0.8 dB with ON-state diodes around 5 GHz. The proposed reflector with ON-state diodes was applied to a dipole antenna reflector and gave equivalent...
In this paper, the transmission and leakage loss of post-wall waveguide depending on the thickness of porous substrate was evaluated. The transmission loss for various thickness of the porous waveguide was simulated in millimeter-wave band by using EM simulator. The valid substrate thickness for improving transmission loss by air-holes was studied. The leakage of the waveguide was also evaluated as...
A new type of bi-layered microstrip antenna (MSA) with conical radiation pattern for mobile satellite communication is proposed as an element antenna in this paper. The MSA consists of three patches with slots on bi-layered substrate and the feed is passing through the ground of the substrate. Thus the element antenna is first coarsely designed and the performance is optimized by electromagnetic simulator...
A compact ultra-wideband (UWB) bandpass filter (BPF) with well matched characteristics is proposed in this paper. The BPF consists of weakly-coupled stepped impedance resonators (SIRs) and parallel-coupled lines. Firstly, the performances of the coupled SIRs were examined, and their results show the broad bandpass characteristics with sharp attenuation slope. Next the bandpass performances of the...
In this paper, design of thin wave absorbers using an admittance-sheet composed of closely placed resistive film and divided conductive film is studied. The admittance of the sheet has frequency dependence because of the mutual influence between the films. The matching frequency of the absorber depends on its thickness (< λ/4) and susceptance of the sheet. Likewise the reflection value at...
In this paper, two-layered wave absorber using short carbon fibers is proposed. The absorber is composed of short carbon fibers, which is attached to polyester fibers on a surface of polystyrene foam, and a metal plate as a reflector. Absorption characteristics of the absorber with one-layer showed that matching frequencies could controlled by the thickness of spacer and the length of carbon fibers...
An ultra-wideband bandpass filter (UWB BPF) which consists of inter-digital finger resonators and impedance inverter lines was studied in this paper. The performances of the UWB BPF of three-fingers were calculated and its performances had the attenuation pole at both passband edges. The stopband attenuation and passband reflection were improved by inserting the inverter lines between the finger structure...
A compact band-stop filter (BSF) using quasi-lumped elements is proposed in this paper. The BSF consists of shunt resonators cascaded by quarter-wavelength transmission lines. The resonator using an inductor line and a parallel plate capacitor as quasi-lumped elements is represented by a series LC lumped resonator. The one plate of the capacitor is placed at the back side of the substrate and spaced...
In this paper, a phased array antenna which has a large number of element antenna and low grating lobes is described. The element antenna has a conical shaped radiation pattern which is suitable for a mobile satellite communications. To reduce a number of phase shifter, partially driven array technique which is one kind of thinned array is employed. The beam scanning characteristics of 243-element...
In this paper, uneven temperature distribution of a heated material is computed by a coupled method considering the change of the complex relative permittivity by the temperature rise. The coupled method can calculate electromagnetics, and all of the heat transmission phenomena of heat conduction, heat transfer by air convection, and heat radiation. The calculated temperature distribution at the surface...
A wave absorber based on rubber sheet with circular lattice using metal mesh is proposed for improving ETC environment, and characteristics of the reflectivity and the shielding effect are evaluated analytically and experimentally. As a result, it is confirmed that the reflectivity of -13dB at the incident angle ranging from 5 to 45 degrees and the shielding effect of -25dB at the incident angle ranging...
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