Mutual coupling reduction in microstrip antennas by using dual layer uniplanar compact EBG (UC-EBG) structure
ABSTRACT Electromagnetic band-gap (EBG) structures can serve in the reduction of mutual coupling by using their capability of suppressing surface waves propagation in a given frequency range. In this paper, a dual layer uni-planar compact EBG (UC-EBG) structure is analyzed and its dispersion diagram is extracted using the commercial finite element full wave solver High Frequency Structure Simulation (HFSS). This UC-EBG structure can be built using planar fabrication technique without any modification. The dual layer UC-EBG structure, having a lower resonant frequency than the single layer one, is inserted between E-plane coupled microstrip antenna arrays to reduce the mutual coupling. This method has been verified by the HFSS simulations and as a result, a significant 17 dB mutual coupling reduction is noticed from the simulations.
Conference Proceeding: Mutual coupling reduction of microstrip antennas using electromagnetic band-gap structure[show abstract] [hide abstract]
ABSTRACT: Microstrip antenna arrays have found broad applications in recent years and the reduction of mutual coupling is an important criterion in their design. The FDTD method is applied to analyze probe fed patch antennas and the simulated results agree well with the experimental results of R.P. Jedlicka et al. (see IEEE Trans. Antennas Propagat., vol.29, p.147-9, 1981). The mutual coupling of patch antennas on a high dielectric constant substrate, which is of growing interest due to its compact size and conformability with MMIC, is characterized in detail. Such antennas have larger mutual coupling than antennas on a low permittivity substrate because of the pronounced surface waves. The electromagnetic band-gap structure introduced by D. Sievenpiper et al. (see IEEE Trans. MTT, vol.47, p.2059-74, 1999) is then employed to inhibit the surface waves so that the mutual coupling is greatly reducedAntennas and Propagation Society International Symposium, 2001. IEEE; 02/2001
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ABSTRACT: Smaller physical size and wider bandwidth are two antenna engineering goals of great interest in the wireless world. To this end, the concept of external substrate perforation is applied to patch antennas in this paper. The goal was to overcome the undesirable features of thick and high dielectric constant substrates for patch antennas without sacrificing any of the desired features, namely, small element size and bandwidth. The idea is to use substrate perforation exterior to the patch to lower the effective dielectric constant of the substrate surrounding the patch. This change in the effective dielectric constant has been observed to help mitigate the unwanted interference pattern of edge diffraction/scattering and leaky waves. The numerical data presented in this paper were generated using the finite-difference time-domain (FDTD) technique. Using this numerical method, a patch antenna was simulated on finite-sized ground planes of two different substrate thicknesses, with and without external substrate perforation. The computations showed the directivity drop in the radiation pattern caused by substrate propagation was noticeably improved by introducing the substrate perforation external to the patch for the case of a patch antenna on a relatively thick substrate without any loss of bandwidth. Measurements of a few patch antennas fabricated on high dielectric constant substrates with and without substrate perforation are included for completeness. Good correlation between the computed results and measurements is observedIEEE Transactions on Antennas and Propagation 01/2000; · 2.33 Impact Factor
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ABSTRACT: A novel waveguide using a photonic bandgap (PBG) structure is presented. The PBG structure is a two-dimensional square lattice with each cell consisting of metal pads and four connecting lines, which are etched on a conductor-backed Duroid substrate. This uniplanar compact PBG structure realizes a magnetic surface in the stopband and is used in the waveguide walls to provide magnetic boundary conditions. A relatively uniform field distribution along the cross section has been measured at frequencies from 9.4 to 10.4 GHz. Phase velocities close to the speed of light have also been observed in the stopband, indicating that TEM mode has been established. A recently developed quasi-Yagi antenna has been employed as a broad-band and efficient waveguide transition. Meanwhile, full-wave simulations using the finite-difference time-domain method provide accurate predictions for the characteristics of both the perfect magnetic conductor impedance surface and the waveguide structure. This novel waveguide structure should find a wide range of applications in different areas, including quasi-optical power combining and the electromagnetic compatibility testingIEEE Transactions on Microwave Theory and Techniques 12/1999; · 2.23 Impact Factor