FDTD analysis of patch antennas on high dielectric-constant substrates surrounded by a soft-and-hard surface (original) (raw)
Related papers
2008
Abstract-- The surface-wave diffraction at the edge of a finite size substrate with a high dielectric constant is the dominant mechanism affecting the radiation pattern of a patch antenna fabricated on this material. A soft-and-hard surface (SHS) can be used to block the surface waves from propagating outward along the dielectric substrate, thus reducing the unwanted diffraction. Patch antennas surrounded by the SHS are analyzed using the finite-difference time-domain (FDTD) technique that implements the SHS boundary conditions using a simple modified subcell model. A square stacked-patch antenna and a circularly polarized (CP) patch antenna on a thick LTCC multilayer substrate are investigated. It is shown that the radiation pattern of the square patch on a big-size substrate can be significantly improved using SHS while the backward radiation level of the CP antenna with SHS on a small-size substrate is considerably reduced. Index Terms—Finite-difference time-domain (FDTD) techniq...
2005
A compact soft/hard surface (SHS) structure consisting of a square ring of shortcircuited metal strips is employed to surround the patch antenna for blocking the surfacewave propagation, thus alleviating the effect of the edge diffraction and hence improving the radiation pattern. The operating frequency of the SHS is determined by the width of the metal strip, therefore it is suitable for a substrate with arbitrary thickness and dielectric constant. The compact SHS structure is realized on a low temperature co-fired ceramics (LTCC) technology. It is shown that the gain of a patch antenna can be increased to near 9 dBi through the use of the proposed compact SHS structure.
IEEE Transactions on Microwave Theory and Techniques, 1999
In this paper, an efficient three-dimensional finite-difference time-domain (FDTD) approach based on the D-, E-, and H-fields is proposed to handle arbitrary anisotropic dielectric media; and, particularly, the way of imposing the electric-wall boundary condition on the surface of perfect electric conductors is discussed in details. By combining the proposed FDTD approach with the material-independent perfectly matched-layer absorbers, the performance of a line-fed microstrip patch antenna deposited on general anisotropic dielectric substrate is investigated. The scattering parameters of the antenna as a function of the rotation angle of the optical axis of the anisotropic substrate are presented for the first time. Numerical results demonstrate how the resonant frequencies of the antenna are influenced by the anisotropy.
2003
The soft-and-hard surface (SHS) is employed to suppress the surface wave generated by a patch antenna integrated with high dielectric-constant LTCC multilayer packages. Two antenna structures are investigated to demonstrate the potential capability of the SHS in surface-wave suppression. The first is a stacked patch antenna on a large-size substrate. It is shown that using SHS can increase the gain at broadside of the patch antenna by almost 10 dB. The second antenna structure is a circularly polarized (CP) patch antenna designed for GPS applications. It is found that the SHS can reduce the backside radiation of the CP antenna on a small-size substrate by more than 14 dB. An observation to near-field distributions shows that the SHS can effectively block the surface-wave propagation on the substrate, therefore alleviating the electromagnetic coupling to the RF circuits
Study of Enhancement Methods for Microstrip Patch Antenna Radiation Patterns Using FDTD Method
The International Conference on Electrical Engineering, 1999
In this paper, two techniques are presented for enhancement of the radiation patterns of a line-fed rectangular patch antenna. The two techniques are based on removal of the substrate under the patch or etching spaced periodic dielectric or air holes in the substrate. The finite-difference time-domain (FDTD) method with perfect matched layer absorber (PML) is applied to determine the return loss, the effective dielectric constant, the input impedance, and the radiation pattern of the proposed structure. The results obtained are found to be in good agreement with the published measured data.
Fdtd Analysis of Stacked Microstrip Antenna With High Gain - Abstract
Journal of Electromagnetic Waves and Applications, 2001
The finite-difference time-domain (FDTD) method is applied to the probe-fed square patch microstrip antenna stacked a parasitic patch for high gain. The input impedance, the directivity, the far field radiation patterns and the near field distributions are calculated and the relation between the antenna structure and the high gain is investigated The calculated input impedance and radiation patterns agree well with the experimental values. When the size of parasitic patch is nearly equal to the fed patch and the distance between the fed patch and the parasitic patch is about a half wavelength, the maximum gain of 9.43 dBi is obtained. In this case, the region between the fed patch and the parasitic patch forms a resonator. Then, the amplitude of current distribution on the parasitic patch becomes large and its phase is opposite to the current on the fed patch. The amplitude of electromagnetic fields of the space between the patches are increased.
The effects of an electromagnetic crystal substrate on a microstrip patch antenna
IEEE Transactions on Antennas and Propagation, 2002
The effects of a two-dimensional (2-D) electromagnetic bandgap substrate on the performance of a microstrip patch antenna are investigated. The microstrip patch antenna is placed on a defect in the electromagnetic bandgap substrate that localizes the energy under the antenna. Finite-difference time-domain calculations are employed to determine the effects of the substrate. The excitation frequency of the antenna near the resonance frequency of the defect mode can be used to control the coupling between antennas that are placed in an array. Index Terms-Electromagnetic bandgap materials, integration, microstrip patch antennas.
Finite difference time domain analysis of a photonic crystal substrate patch antenna
Physica B: Condensed Matter, 2005
Planar microstrip patch antennas can achieve a wide range of radiation patterns. However, due to surface-wave losses, they have low bandwidth, low gain, and a potential decrease in radiation efficiency. In order to minimize the surface-wave effects, a photonic-band gap (PBG) substrate is proposed. The PBG structure significantly diminishes the surface-wave modes and thus improves the gain and far-field radiation pattern and efficiency. In this paper, using FDTD, an accurate full-wave analysis of surface-wave propagation in a rectangular microstrip patch antenna with and without PBG is presented. Finally, the antenna fabricated and result of measurement was compared with numerical simulation. r
Performance Analysis of Antenna Using Fdtd
2017
Microstrip patch antennas are widely used because of thin profile, light weight, low cost; conformability to shaped surface and compatibility with integrated circuits. In order to increase the strengths of antenna using time domain method, a micro strip patch antenna is directly treated in the time domain, using modified Finite Difference Time Domain (FDTD) method. The Finite Difference Time Domain (FDTD) method, first introduced by Yee, is a powerful, robust, and popular modelling algorithm based on the direct numerical solution of Maxwell’sequationsin the differential, time domain form. The most important feature of the FDTD method is that broad-band frequency information can be provided in a single pass simulation. It has been extensively used in the parameter extraction of wave guides, micro strip circuits and multiple coupled lines. Broad band characteristics of network parameters such as input impedance, scattering parameters are calculated from time domain simulated data. The...
TE Surface Wave Resonances on High-Impedance Surface Based Antennas: Analysis and Modeling
IEEE Transactions on Antennas and Propagation, 2000
Low-profile antennas comprising a horizontal dipole above a high-impedance surface are analyzed. The emphasis of this paper is on the additional resonances of the radiating structure caused by surface waves propagating on the high-impedance surface. It is shown that such resonances can be favorably used for broadening the bandwidth of the antenna. The phenomenon is thoroughly modeled by exploiting a parallel between the HIS structure and a waveguide resonator. In the second part of the paper we discuss homogenized approaches for modeling the radiating properties of the antenna with emphasis to the phenomenon discussed in the first part. As it turns out, it is necessary to take into account the spatially dispersive properties of high-impedance surfaces, and most of the simplified models commonly used for analyzing high-impedance surface based antennas fail in predicting the discussed resonance mode. Index Terms-Artificial magnetic conductor (AMC), electromagnetic bandgap (EBG), frequency selective surfaces (FSS), high impedance surfaces (HIS), metamaterials.