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This paper proposes novel reflectarray elements by arranging double omega-shaped resonant strips with mirror image for converting a linearly polarized incident wave into a circularly polarized radiated wave. As a design example, a linear-to-circular polarizer reflectarray is presented and also its polarization property of far-field patterns over 12–17 GHz is discussed numerically and experimentally.
For covering a specified wide circular area with a tilted sectoral beam, this paper proposes compact beam-tilted multimode horns based on coaxial dual-path guides and shaped dielectric-lens onto the horn aperture. We present two design examples with a beam tilted up to 20 degrees for 24 GHz radio-sensor systems. One is constructed with an axially symmetrical structure and also is fed by a bend waveguide,...
Recently, a cloaking technology using reflecting elements has been marked. Cloaking devices using reflectarray have simple and very thin structure, so they are especially suitable for cloaking. This paper proposes a carpet cloaking using wideband reflectarray.
This paper proposes novel reflectarray resonant elements for broadband orthogonal polarization conversion designed by genetic algorithm(GA). These elements have two axially symmetrical structure to realize the phase difference of −180° between the orthogonal two linearly polarized waves, while keeping the reflection-phase range of 360° with the linearly phase-curves from 13 GHz to 17 GHz.
This paper presents reflectarray resonant elements for orthogonal polarization conversion designed by using the genetic algorithm(GA). These elements have orthogonal two axially symmetrical structure which can be realized that the phase-difference (−180° or 180°) between the TE and the TM incidences, while achieving the reflection-phase range of 360° at the center frequency 15 GHz.
This paper proposes a new rectangular horn for orthogonal polarized elliptical beams. This consists of two sectoral horns, of which sidewalls have grooves its design is performed by optimization based on the mode-matching method. As a design example, we present a horn with −10 dB beam widths of 33° × 100° at 10 GHz. Effectiveness of the designed horn is verified numerically and experimentally.
This paper proposes a primary radiator using leaky-wave antenna with left-handed cylindrical waveguide. Negative permeability is realized by the cutoff TM01 mode in a hollow waveguide and also negative permittivity is realized by the cutoff dominant TE mode in a sector waveguide with a ridge. Then the left-handed leaky-wave antenna with slits opened is applied to a primary radiator without sub-reflecting...
This paper proposes an approach to design the carpet cloak by using reflecting elements. Using such a technique, it is possible to realize invisibility by thinner cloaks. Furthermore, an illusion cloaking using the metasurface is investigated numerically and experimentally.
This paper proposes arbitrary shaped elements for linear-to-circular polarizer for reflectarray. We optimized the resonant elements with orthogonal two axial symmetry by the genetic algorithm(GA). Moreover, the effectiveness of the proposed elements is verified by discussing radiation characteristics of a fabricated offset reflectarray numerically and experimentally.
Composite right/left-handed (CRLH) rectangular waveguides has been proposed. In the waveguides, negative permeability is realized by the cutoff TM11 mode, of which electromagnetic field distribution is similar to that of a coaxial-line TEM mode. On the other hand, negative permittivity is realized by the cutoff TE mode in the waveguides divided into 4 sections by an H-shaped conductor partition. It...
This paper presents a novel reflectarray elements for linear-to-circular polarizer. Frequency properties of the proposed resonant elements provide almost linear phase curves with the same slop, while achieving the reflection phase range of 360°. The phase difference between the V-pol. and the H-pol. is about 90° more than the fractional bandwidth 10 %(cross polarization level <–15dB and axial ratio...
This paper has proposed a method constructing composite right/left-handed cylindrical waveguides. In this waveguide, negative permeability is realized by the cut-off TM01 mode in a hollow waveguide and also negative permittivity is realized by the cutoff dominant TE mode in a sector waveguide with a ridge. Usefulness of the proposed cylindrical waveguide is verified from the calculated values for...
This paper proposes novel reflectarray elements with four axial symmetry(including axial and rotational symmetry) for dual-polarization and wideband use. These elements provide reflection phase range of 360° over the wide frequency range by changing their shapes, and also have low cross polarization properties. We design an offset feed reflectarray constructed by the proposed elements in the Ku-band,...
This paper proposes new composite right/left-handed (CRLH) cylindrical waveguides based on the cutoff TE- and the TM-modes. The calculated transmission characteristics of the proposed waveguide are presented, and also the proposed waveguide is applied to a leaky-wave antenna. Its effectiveness is numerically verified from the radiation patterns.
Directional coupler with two-layered microstrip line couples through slot aperture on the common ground, so that the tight coupling in compact size is easily realized. This paper proposes to improve the frequency characteristic by loading strip conductors on the slot aperture and also by arranging the input and the output ports rotational-symmetrically. Usefulness of the proposed directional coupler...
A bandpass-filter based on the Cul-de-Sac coupling matrix has been proposed here. The filter is constructed by the open-loop microstrip resonators on two dielectric substrates separated by the ground plane and uses two kinds of aperture-couplings between the resonators. As an example, the fifth-order bandpass filter is designed and fabricated, and its filter characteristics is measured to compare...
This paper proposes the design method of such elements by using the genetic algorithm(GA). In design of a reflectarray, to reduce a phase error on the aperture, we need to find a group of elements with arbitrary reflection phase value over the range of 360 degrees. Besides, it is desirable that their elements have a low cross-polarization and dual-polarization property to enhance antenna performance...
In this paper, we propose a novel unit-cell structure of composite right/left handed transmission line satisfying the balanced condition. This structure is constructed by changing the shape of the main track to adjust the value of the series inductor. As a result, the unit cell group without a band-gap is found. The effectiveness of the proposed unit-cell is verified from the radiation patterns of...
A waveguide filter loading frequency selective surface (FSS) is very useful, because it make attenuation poles without using any additional couplings and structures. This kinds of the conventional filters must take the interval of a quarter-wavelength between the adjacent FSSs. So, we first exhibit that a very thin filter can be constructed by the FSSs with the “U”-shaped slot-loaded patch. However,...
This paper proposes new reflectarray elements for dual-polarization wideband use. These elements provide low cross polarization property and almost linear phase property for the frequency, thereby achieving the desirable reflection phase over the wide frequency range. To verify effectiveness of the proposed elements, a reflectarray with offset feed is constructed by them, and also is wideband frequency...
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