Modal Analysis of Microstrip Antenna on Fiber Reinforced Anisotropic Substrates

Abstract

In this communication, microstrip antenna on fiber reinforced anisotropic substrates has been considered in aerospace applications; however, the antenna's optical axis may not necessarily be colinear with any of the substrate's principal axes and that leads to a nondiagonal permittivity matrix (tensor). This work extends the studies of microstrip antenna on isotropic substrate and on uniaxial substrate to analyze antenna performance on fiber reinforced anisotropic substrates, where the permittivity matrix has five dielectric constants because of the substrate's fiber direction. The solution is based on modal analysis so that the wave immittance can be derived in a closed form. Analyses and experimental verification show that the antenna performance is strongly influenced not only by the permittivity along the principal axes but also by the fiber direction of the substrate.Index Terms-Anisotropic substrate, microstrip antenna, spectral domain analysis.

The effect of dielectric overlay on microstrip antenna embedded in composite laminated substrates

“…The antenna size in composite laminated substrates will always be larger than that on isotropic substrate, or conversely, the resonant frequency will deviate lower from the desired frequency if mistakenly treating the laminated substrates as isotropic. This prediction confirms the previous work [15] that antenna design without knowing the substrate's anisotropic property can be erroneous because the layer's anisotropic ratio is critical to antenna performance. The antenna embedded in [45/À45/45/45/À45/45] symmetric balanced substrate without overlay is square with L/L iso = 1.205, and with the overlay, it becomes larger in size at L/L iso = 1.219.…”

“…Analytical solutions, if available, would be desirable to conduct parametric study of the substrate's variable affecting the antenna performance. The wave equations and the electric and magnetic fields of microstrip antenna on a single anisotropic layer in spectral domain have been derived in []. The equations for a composite laminated substrate composed of N laminate layers are similar, where the electromagnetic wave propagation of the i th laminate layer can be solved by the electric and magnetic Hertzian potentials Π h and Π e where and are the unit vectors for coordinate transformation between the antenna's x‐y‐z axes and the substrate's 1‐2‐3 axes in Figure (a).…”

“…In spectral domain analysis, the current components are solved by modal analysis in terms of base functions. For a rectangular microstrip antenna of dimension L × W , it has been shown that one‐mode expansion by the base functions can achieve good accuracy , where δ (•) is the Dirac delta function. By substituting Eqs.…”

“…Analytical solutions, if available, would be desirable to conduct parametric study of the substrate's variable affecting the antenna performance. The wave equations and the electric and magnetic fields of microstrip antenna on a single anisotropic layer in spectral domain have been derived in [15]. The equations for a composite laminated substrate composed of N laminate layers are similar, where the electromagnetic wave propagation of the i th laminate layer can be solved by the electric and magnetic Hertzian potentials Π h and Π e…”

Mutual coupling between coax-fed rectangular microstrip antennas embedded in layered uniaxial anisotropic dielectrics

“…Whether this anisotropy is an unintended consequence of the manufacturing process or not, its effects on the performance of antennas and other devices can be appreciable. As a recent example, the orientation of a microstrip antenna on a fiber-reinforced substrate was shown to appreciably affect the resonant frequency of the antenna and its radiation pattern [5].…”