Finite and infinite element analysis of coupled cylindrical microstrip line in a nonhomogeneous dielectric media

Abstract

An effective method for computing the parameters of coupled cylindrical microstrip line system is presented in this paper. Consider a cylindrical microstrip line cross-sectional configuration consisking of two concentric cylindrical dielectric substrates shown in Fig. 1. Two arbitrary number C1 and CZ of infinitesimally thin arc strips of the arbitrairy size (a1 I SI 5 P I ) and (a2 5 S2 5 ,&) are clad on the dielectric Cylindrical interfaces. The dielectric cylinders are characterized by real scalar permittivity ci and permeability po while the region outside of the dielectric cylinders is free space providing constitutive parameters eo and p o , respectively. The two conductors are charged by VI and Vz while the CO is grounded. Coupled microstrip line system are used for many applications including filters, couplers, transition adaptors, baluns, and impedance matchiing networks. These lines can also be used to excite printed antennas on cylindrical structures. The anallysis is based on finite and infinite element methods and the quasi-static T EM mode approximation. The quasistatic TEM is essentially a low frequency model of microstrip line that can be concerned the existence of electric and magnetic fields separately. The microstrip line system is analyzed with both the ordinary finite to discretize the ili bounded region and globa,l exterior infinite element to cover the s1, unbounded domain shown in Fig. 2. The potential and field distribution in the cross section of the microstrip line are determined by minimizing the energy functional of the Laplace's equation using variational principle. Then it can be used to calculate the Maxwellian capacitance or inductance matrix per unit length of the microstrip line. The parameters of the microstrip line can be determined in terms of the capacitance or inductance matrix. The equivalent circuit for the coupled microstrip lines is developed and its application to the solution of wave propagation modes is clemonstrated. In this investigations, the accurate solution of characteristic impedance, effective dielectric constant, attenuation, coupling, propagation constant, and so on has analyzed in terms of the capacitance matrix. These parameters are important in designing of microstrip lines, strip lines, and transmission lines applied in microwave integrated circuits, digital circuits, communications, radars, and other applicationa.

Analysis of Cylindrical Microstrip Line with Finite Thickness of Conductor

“…Recently, curved surface substrates have attracted an attention as materials of antennas and front ends for portable terminals. A lot of analyses of the propagation characteristic of the stripline and the coplanar waveguide composed on a cylinder substrate are reported [1][2][3][4][5][6], including the moment method, the FDTD method [3], and the finite element method [5]. However, their works assumed the conductor thickness to be zero, and the report concerning the effect of the conductor thickness on the propagation characteristic has not be found.…”

Design and Characterization of Modified Comb Patch Antennas

“…In this framework, comb antennas have been analyzed by developing models based on variational methods [22], modal analysis [23], or simple, but less accurate transmission line models (TLM) [24]- [26] or computationally costly, high-fidelity full-wave analysis (FW) [8], [27]- [33]. All these design strategies are often complemented by numerical optimization, heuristic or machine learning-based methods [34]- [38]. As a matter of fact, when designing the aforementioned comb antennas usually, the design strategy is mostly heuristic and driven by extensive numerical simulations [21], reflecting a poor theoretical effort [11], [13], thus highlighting the lack of a complete, exhaustive and simple model for the analysis of comb antennas.…”