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A diamond-shaped grid array antenna (GAA) printed on a dielectric substrate (DM-GAA-Dielectric) is analyzed using an integral equation, which includes Sommerfeld-type integrations, with the method of moments. The radiation characteristics of the DM-GAA-Dielectric are compared with those of a GAA composed of rectangular elements (Rect-GAA-Dielectric). It is revealed that the diamond shape increases...
A beam-steerable antenna system that forms unidirectional radiation is presented. A bundle of transmission lines is used for exciting parasitic elements that are circularly arrayed. The beam direction is controlled by leaving a group of consecutive parasitic elements open-circuited, while shorting the remaining parasitic elements to the ground plane. A reconfigurable antenna with a gain of approximately...
Modified monopole (MM) elements are circularly arrayed on a conducting plate (ground plane). The MMs act as parasitic elements for a central active element. The bottom end of each MM element is either open-circuited or short-circuited with respect to the ground plane. The analysis is performed to reveal the radiation characteristics of the MM array, including the radiation pattern, gain, and VSWR...
A grid array antenna (GAA) printed on a dielectric substrate is analyzed using the finite-difference time-domain method (FDTDM) to validate the method of moments (MoM) results. The GAA is excited by a vertical probe that is connected to the inner conductor of a coaxial line. The radiation characteristics and the computation time using the FDTDM are compared with those using the MoM.
The radiation characteristics for a grid array antenna printed on a dielectric substrate (PGAA) excited in unbalanced mode (UnBal-PGAA) are analyzed using an integral equation with the method of moments (MoM). The UnBal-PGAA radiates a linearly polarized beam in the broadside direction. It is found that a difference in the excitation modes (balance and unbalance) does not affect remarkably the half-power...
The radiation characteristics of a diamond array (DA) of diamond elements are calculated using the method of moments. It is found that the maximum gain for the DA is higher than that for a conventional grid array antenna (GAA). It is also found that the frequency bandwidth of the gain for the DA is slightly narrower than that for the conventional GAA.
The radiation characteristics of a grid array antenna composed of rectangular loop cells are investigated using the method of moments. It is found that, as the size of the rectangular loop cell is increased, the frequency response curve for the gain shifts toward the lower frequency region. However, the gain frequency bandwidth remains almost unchanged.
The radiation characteristics of a grid array antenna composed of diamond-shaped cells (DM-GAA) are analyzed using an integral equation with the method of moments. It is revealed that the gain for the DM-GAA is higher than that for a conventional GAA. The side lobe level is less than − 20 dB.
The radiation characteristics of an antenna consisting of two pairs of bowtie-shaped grids are analyzed. A circularly polarized beam in the broadside direction is obtained when the four input terminals are appropriately excited. An improvement (reduction) in the cross-polarized component is realized and discussed.
The radiation characteristics of a grid array antenna for one-line excitation are investigated using the method of moments. This grid radiates a dual-beam. It is revealed that the co-polarized electric field components are the same in the two principal planes. The direction of maximum radiation and the gain are discussed.
The radiation characteristics of a bowtie-shaped grid array antenna (BT-GAA) is analyzed using the method of moments. It is found that linearly polarized (LP) and circularly polarized (CP) beams are radiated from the BT-GAA by appropriately choosing excitation phases of the feed terminals. It is also found that the BT-GAA acts as horizontal and vertical LP antennas and right- and left-handed CP antennas.
The circularly polarized radiation characteristics of a bowtie-shaped grid array antenna (BTS-GAA) are investigated in order to broaden the area of application. It is found that a circularly polarized beam is obtained by appropriately choosing the amplitudes and phases of the feeding voltages. It is also found that the BTS-GAA acts as an antenna of dual circular polarization.
In this paper, we consider how patch width W and length L effect the center frequency and return loss by electromagnetic field simulator. Then, we find optimum value of W and L at 20 GHz, when slot length S is 1.0 mm and displacement between center of patch and slot D is 0 mm. On the basis of the result, we modify the design formula of patch width W.
A grid array antenna (GAA) printed on a dielectric substrate is investigated to obtain dual-beam radiation. For the analysis of the GAA, the method of moments (MoM) is applied to an integral equation expressed by Sommerfeld-type integrals. It is revealed that the maximum beam direction, gain, and half-power beam width in the principal plane are changed with frequency. The dual-beam radiation is obtained,...
The frequency characteristics of a grid array antenna printed on a dielectric substrate are revealed using the method of moments (MoM). It is found that the grid array antenna radiates a dual beam when the operating frequency is appropriately chosen. The direction of the maximum radiation is changed with frequency, with a change in the gain.
We have investigated the scattered field by an impedance discontinuity of a planar surface. A reference solution has been derived by using the Helmholtz-Krichhoff (H-K) integral theorem, while an asymptotic solution has been derived by using the aperture field method (AFM) and the saddle point technique. The validity and utility of the asymptotic solution have been confirmed by comparing with the...
In this paper, we have studied on scattered fields of the electromagnetic wave by an impedance discontinuity of a planar surface. Based on the aperture field method (AFM), an integral representation for the scattered fields at a receiving antenna is derived, and an asymptotic solution is obtained by using the saddle point technique. We have compared the asymptotic solution composed of the reflected...
In this study, we have derived a reference solution from the Green's theorem and the Helmholtz-Kirchhoff integral theorem for reflected and scattered fields by a discontinuity of a planar impedance surface. It is assumed that both the transmitting and receiving antennas are placed sufficiently above the planar impedance surface. We have also derived a high-frequency asymptotic solution including higher-order...
We derive an extended UTD (uniform geometrical theory of diffraction) solution for the high-frequency scattered fields by a coated conducting cylinder covered by a thin lossy dielectric material. We show that the exended UTD solution derived by retaining the higher order term can be applied uniformly in the transition region near the shadow boundary and in the deep shadow region. The validity of the...
The problems of an electromagnetic wave that is incident on a plane dielectric interface consisting of two different mediums have been the important research subjects for many years [1]–[10]. When the beam is incident on the dielectric interface from the denser medium, the lateral displacement (or Goos-Hänchen shift) occurs at an angle that is slightly larger than the critical angle of the total reflection...
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