Input impedance and mutual coupling of spherical rectangular microstrip patch antennas

A combination of a multiresolution (MR) preconditioner and matrix decomposition algorithm – singular value decomposition (MDA-SVD) algorithm is proposed for the analysis of densely discretised electromagnetic (EM) scatterers. In realistic EM scattering problems, the discretisation may be very dense to accurately describe the geometric shape of targets. However, dense discretisations will generate two major drawbacks: (i) the badly conditioned method of moments (MoM) matrix which makes iterative solvers difficult to converge; (ii) the dense near-field MoM matrix for which the computational cost is large, even multilevel fast multipole algorithm (MLFMA) is applied. To remedy the first shortcoming of dense discretisations, an MR preconditioner can be applied to improve the condition of MoM matrices. To reduce the computational cost in solving the MoM matrix equation, an MDA-SVD algorithm can be applied to accelerate the matrix−vector multiplication. Compared with the traditional MLFMA, the MDA-SVD algorithm has no limit on the size of octree boxes which makes the MDA-SVD algorithm suitable for the analysis of dense discretisations. Therefore an MR preconditioner is combined with the MDA-SVD algorithm for fast analysis of dense discretisations. Numerical results indicate that the combination of the MR preconditioner and the MDA-SVD algorithm is efficient.

Summary form only given. Fast direct integral equations methods for analyzing time-harmonic scattering phenomena constitute an active area of research in the CEM community. These solvers present an interesting alternative to FMM-based iterative schemes for problems that are inherently ill-conditioned and/or involve many excitations. Present fast direct methods leverage the low-rank (LR) nature of blocks of the LU factors or inverse of the method of moment (MoM) matrix (if and when this property manifests itself). In essence, they leverage the limited number of degrees of freedom of the fields radiated by sources in the presence of the scatterer (or portions thereof), observed across a finite region of the scatterer (whenever the concept makes sense). LR compression strategies do not lead to low-complexity solvers for electrically large concave structures. This fact was demonstrated in [H. Guo et al., Antennas and Wireless Propagation Letters, IEEE, vol. 11, 2012], where blocks of LU factors that proved incompressible by LR methods were recompressed by MLMDA/butterfly methods. Somewhat unexpectedly, this study showed that MLMDA/butterfly scheme produced compression above and beyond that provided by LR schemes, requiring only O(N log2 N) final storage irrespective of the nature or electrical size of the scatterer. The practical applicability of the scheme however was severely hindered by the fact that the MLMDA/butterfly scheme acted as an add-on to a LR solver. Here, we report on a new direct integral equation solver by that utilizes MLMDA/butterfly schemes for compressing the LU factors of a MoM matrix. When compared to its predecessor, the new solver has three important features of note. (i) The solver entirely bypasses the LR compression step of its predecessor and operates directly on butterfly-compressed blocks. The latter is achieved using new schemes for rapidly adding and multiplying butterfly-compressed operators. (ii) The solver executes in parallel, using a hybrid OpenMP-MPI strategy to accelerate the hierarchical inverse/decomposition of the MoM matrix. Despite the inherently sequential nature of this operation, the solver exhibits excellent scaling properties up to several hundred processors. (iii) The solver applies to large-scale 3D (as opposed to 2D) analysis and was implemented to invert a combined field (as opposed to an electric field) integral operator. The solver is capable of inverting MoM matrices that discretize combined field integral equations modeling scattering from electrically large structures involving millions of unknowns on a small cluster using just a few hours of CPU time.

Theory and experiment of a spherical probe-fed conformal antenna with a parasitic element mounted on a spherical multilayer structure are presented in this paper. Rigorous mathematical Method of Moments (MoMs) for analyzing various radiating spherical structures is presented in this paper by using Dyadic Green's Functions (DGFs) in conjunction with Mixed Potential Integral Equation (MPIE) formulation. Linear Rao-Wilton-Glisson (RWG) triangular basis functions are applied in MPIE formulation. Current distributions on coaxial probe and conformal radiating elements are computed by using spatial domain Dyadic Green's Function (DGF) and its asymptotic approximation. A prototype of such an antenna is fabricated and tested. The effect of the parasitic element on the input impedance and radiation patterns of the antenna is investigated. It is shown that the antenna characteristics are improved significantly with the presence of the conducting parasitic element. Good agreement is achieved between the results obtained from the proposed methods and the measurement results.

This paper presented a full-wave analysis of a spherical rectangular microstrip antenna using method of moments, emphasizing the use of an attaching current in the modeling of the patch currents and calculation of its input impedance

The modified Wolff model (MWM)‐based cavity model is presented for the simple and accurate computation of the input impedance of a probe‐fed multilayer rectangular microstrip patch antenna. Results of the MWM are compared with both the experimental data and data of the MoM, with agreement within 1.5% for resonance frequency and within 0.15 for normalized input impedance. Further results are presented on the input impedance of a suspended rectangular microstrip patch antenna with a two‐layer superstrate. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 237–239, 2001.

Array scanning method (ASM) is employed to study the input impedance and radiation pattern of a two-dimensional periodic leaky-wave antenna (LWA). The antenna consists of a narrow horizontal strip dipole of arbitrary length underneath a two-dimensional (2D) periodic screen of metallic patches, which acts as a partially reflective surface (PRS), and backed by a ground plane. First, the Green's function in the presence of the 2D array of metallic patches is calculated by means of the ASM and then the current distribution and input impedance of the source dipole are calculated through the electric field integral equation and method of moments. The far-field pattern is computed using the reciprocity theorem. Compared to the Hertzian dipole, which is the only type of source that has been considered in the literature, the resonant dipole substantially improves the performance of periodic LWA in terms of radiated power, efficiency and bandwidth. Numerical results are given for a resonant dipole over the frequency range of 60-70 GHz and compared with those obtained from commercial softwares, FEKO ® and Ansys HFSS ® , showing an excellent agreement with considerable improvement in terms of memory usage and computational speed.

Theory and experiment of a spherical probe-fed conformal antenna with a parasitic element mounted on a spherical multilayer structure are presented in this paper. Linear Rao-Wilton-Glisson (RWG) triangular basis functions are applied in MPIE formulation. Current distributions on coaxial probe and conformal radiating elements are computed by using spatial domain Dyadic Green's Function (DGF) and its asymptotic approximation. A prototype of such an antenna is fabricated and tested. The effect of the parasitic element on the input impedance and radiation patterns of the antenna is investigated. It is shown that the antenna characteristics are improved significantly with the presence of the conducting parasitic element. Good agreement is achieved between the results obtained from the proposed methods and the measurement results.

Spherical arrays present a natural choice if complete hemispherical coverage with nearly constant beam width is needed. In this article, circular stacked-patch antennas embedded in a multilayer spherical structure are analyzed using the spectral-domain approach and the moment method. The influence of structure radius on input impedance and radiation pattern is investigated. The results confirm the importance of rigorous analysis of curved patch antennas. Furthermore, a laboratory model is built to validate the developed program. The agreement between measured and calculated results is good

An analysis of the input impedance of. a Rectangular Dielectric Resonator Antenna (RDRA) operated at the dominant mode TE/sub 111/ is presented. The effects of the probe length and its position with respect to the resonator on the resonance frequency and the input impedance of the antenna are investigated. The antenna structure is numerically simulated using the High Frequency Structure Simulator (HFSS) software package based on the Finite Element Method (FEM). A few experimental set-ups were examined and resonance frequency and input impedance were measured. The results show good agreement between theory and experiments and also the significance of the distance between the resonator and feed probe in simulation.

This paper presents a non-destructive, non-invasive method for measuring the input impedance of a Radio Frequency Identification (RFID) transponder (tag) antenna at the operating frequency The derivation of the theoretical basis for determining the antenna impedance is presented along with the experimental measurement method using a Vector Network Analyzer (VNA) in conjunction with a Giga-Hertz Transverse Electromagnetic (GTEM) cell where the tag is located. By providing three different terminations to the antenna, the frequency dependent parameters can be measured in order to define a two-port network and determine the input impedance of the antenna. All measurements were performed using the actual RFID tag that operates in UHF (915 MHz) band. The resulting input impedance of the antenna was validated with the electromagnetic simulation software by constructing a model of the testing system and applying the proposed measurement method. The simulated results were found to be in agreement with the experimental measurements accounting for any discrepancies.

This paper discusses the parametric study of Microstrip Patch Antenna. A simple Rectangular Microstrip Patch Antenna (RMSA) was designed and simulated using Zeland's Method of Moment (MoM) based EM simulation package IE3D and its various parameters such as return loss, VSWR and input impedance were obtained. Then effect of change of width, lenght, loss tangent, feed location, etc is observe on above parameters.

We consider the problem of excitation of a cylindrical microstrip antenna fed by a cylindrical microstrip line. The problem has been solved by the moments method in the spatial domain using a new representation of the Green’s function. In the model proposed, a cylindrical microstrip line of finite length is attached to the patch and is considered as its part. The so-called lumped delta generator is chosen as the excitation source. At the first stage, current distributions on the patch and in the microstrip line are found by solution of the integral equation. Then using the well-known relations of the transmission-line theory and the equivalent-scheme method, we calculate the reflection coefficient in the microstrip line and the antenna input impedance. Patches of different shapes are discussed.

The ability of the finite-difference-time-domain (FDTD) method to calculate radiation patterns, input impedance, and gain for a monopole antenna on a conducting box is demonstrated. Results are given for the bare box and with the box coated with a dielectric layer. Radiation patterns are compared with measurements and with the method of moments for the bare box. Radiation patterns for the dielectric-covered box and all impedance and gain results are compared with measurements only. Good agreement is obtained in all cases. The FDTD approach includes a dielectric covering quite easily, while this would be quite difficult for a method of moments approach. The FDTD method requires similar computer time as the method of moments for a single-frequency result, but produces wide-bandwidth impedance and gain results with much less computer time. >

A compact single asymmetric coplanar waveguide feed (ACPW‐fed) dual circularly polarized microstrip antenna that operates at 1.8, 3.9, and 5.2 GHz in the entire operating frequency band 600 MHz–6 GHz for the radar detection of the improvised explosive devices (IEDs) carried by a person is introduced. The proposed novel quasi‐omnidirectional antenna consists of single sided rectangular ring microstrip patch antenna. L‐shaped slots are etched at the two opposite corners of the rectangular ring, introducing new resonance and circular polarization waves at the mid and upper bands, respectively. The achieved dual half‐rectangular ring patch antenna (DHRR‐patch) is loaded with strips of various shapes delicately placed at the center of the radiator, providing new resonance at the upper band and the improvement of the CP features. The matching technique designed based on CPW 50 Ω microstrip transmission line combined with the dual broad band matching techniques through quarter‐wave transformer in conjunction with open stubs and distributed lumped element method constitutes the novelty of the study. Based on quasi‐TEM mn (q‐TEM mn ) mode, ACPW‐fed and CP‐slots are employed to generate CP radiations at the q‐TEM 11 and q‐TEM 21 modes, respectively, while the ground plane width is optimized to enhance axial ratio bandwidth (AR‐BW). Input impedance and radiation pattern calculations of the conventional structure using transmission line and cavity model‐based q‐TEM 01 mode are conducted, respectively. Numerical experiments of the studied monolayer antenna are carried out using Advanced Design System (ADS) Version 2009 environment software employing internal one‐port option to excite the antenna. The prototype of the proposed antenna with a compact dimension (0.27 λ g × 0.38 λ g × 0.02 λ g at 1.8 GHz where λ g is the guided wavelength of the q‐TEM 01 mode) is fabricated on high loss laminate FR4 substrate of volume 43 × 38 × 1.6 (mm 3 ) and relative dielectric constant of 4.4 with simple laboratory‐based traditional printed circuit board (PCB) etching process. Measurement results show a fractional impedance bandwidth (FIBW) of 11.1%, 5.9%, and 7.1%, axial ratio (AR) of 4.6, 2.2, and 0.5 dB, and peak gain of 3.7, 4.7, and 6.1 dBic at 1.8, 4.0, and 5.2 GHz, respectively, demonstrating its suitability for IED detection applications. To verify the efficiency of the proposed model, measured results are compared with the simulated results and good agreement has been established.

This paper presents comparison of rectangular micro strip patch antenna and E-Shaped micro strip patch antenna operating at 2.45GHz. Two parallel slots are made into the basic rectangular patch design of micro strip antenna which resulted into desired E-shaped patch. The basic design consist of inset feed type and we have used dielectric substrate Fr4 epoxy whereas E-shaped patch consist of coaxial probe and RT Duroid as substrate. Both the designs have been implemented using HFSS software. On comparing the parameters of both the antenna’s design, it was observed that E-shaped patch antenna has enhanced gain and return loss, hence the antenna with enhanced parameters is considered, the better one. Keywords : Rectangular patch antenna, Micro strip patch, E-shaped patch, coaxial feed Cite this Article Priya Sharma, Shreya Ghare, Shruti Jain, Archana Tiwari. Design and Simulation of E-Shape Micro-strip Patch Antenna at 2.45GHz. Journal of Microwave Engineering & Technologies . 2020; 7(1): 17–24p.