Wlodzimierz Zieniutycz

Expedited EM-Driven Multiobjective Antenna Design in Highly Dimensional Parameter Spaces

A technique for low-cost multiobjective optimization of antennas in highly dimensional parameter spaces is presented. The optimization procedure is expedited by exploiting fast surrogate models, including coarse-discretization electromagnetic (EM) antenna simulations and response surface approximations (RSA). The latter is utilized to yield an initial set of Pareto nondominated designs that are further refined using response correction methods. Efficient handling of multiple geometry parameters is realized by the initial reduction of the solution space. Our approach is demonstrated using a 13-parameter triple trapezoidal, planar ultrawideband (UWB) monopole antenna.

Design of a Planar UWB Dipole Antenna With an Integrated Balun Using Surrogate-Based Optimization

A design of an ultrawideband (UWB) antenna with an integrated balun is presented. A fully planar balun configuration interfacing the microstrip input of the structure to the coplanar stripline (CPS) input of the dipole antenna is introduced. The electromagnetic (EM) model of the structure of interest includes the dipole, the balun, and the microstrip input to account for coupling and radiation effects over the UWB band. The EM model is then adjusted for low reflection over the UWB band by means of fast simulation-driven surrogate-based optimization. This approach allows us to obtain the final design at low computational costs and at a high-fidelity level of structure description. Measurements of the manufactured optimal design validate the use of the balun as well as the design approach.

Rectangular Microstrip Resonator Illuminated by Normal-Incident Plane Wave

In the paper, an Illuminating Modes concept is introduced in order to flnd microstrip antenna parameters | resonant frequency, resonant resistance and radiation pattern. The concept is based on illuminating the rectangular patch by a single normally-incident plane wave. It results in the surface current density induced on the patch which is found by means of two-dimensional Spectral Domain Approach. Then, the resonant frequency, the quality factor, the resonant resistance and the radiation pattern of the analysed antenna are found. Application of Illuminating Mode concept in Spectral Domain Approach efiects in analysis simpliflcation and less time consuming calculations with no waste of the accuracy. Exemplary results for several kinds of radiators are presented, showing satisfactory level of agreement with published data.

Design Space Reduction for Expedited Multi-Objective Design Optimization of Antennas in Highly Dimensional Spaces

A surrogate-based technique for efficient multi-objective antenna optimization is discussed. Our approach exploits response surface approximation (RSA) model constructed from low-fidelity antenna model data (here, obtained through coarse-discretization electromagnetic simulations). The RSA model enables fast determination of the best available trade-offs between conflicting design goals. The cost of RSA model construction for multi-parameter antennas is significantly lowered through initial design space reduction. Optimization of the response surface approximation model is carried out by a multi-objective evolutionary algorithm (MOEA). Additional response correction techniques are subsequently applied to improve selected designs at the level of high-fidelity electromagnetic antenna model. The refined designs constitute the final Pareto set representation. The presented multi-objective design approach is validated using three examples: a six-variable ultra-wideband dipole antenna, an eight-variable planar Yagi-Uda antenna, and an ultra-wideband monocone with 13 design variables.

Expedited Design of Microstrip Antenna Subarrays Using Surrogate-Based Optimization

Computationally efficient simulation-driven design of microstrip antenna subarrays is presented. The proposed design approach aims at simultaneous adjustment of all relevant geometry parameters of the subarray, which allows us to take into account the effect of the feeding network on the subarray radiation pattern [in particular, the sidelobe level (SLL)]. In order to handle a large number of variables involved in the design process, a surrogate-based optimization procedure is proposed that exploits electromagnetic (EM) array simulations of variable fidelity and suitably designed correction techniques. The penalty function approach allows us to minimize SLL while maintaining array matching at a required level. The optimized designs are obtained at the low computational cost corresponding to a few high-fidelity subarray simulations. Experimental validation of the manufactured designs of microstrip subarrays operating at 10 GHz is also provided.

Double-ridged Horn Antenna with Sinusoidal Ridge Profile

FDTD numerical study compared to the results of measurement is reported for double-ridged horn antenna with sinusoidal profile of the ridge. Different transitions from coaxial to double-ridged waveguide were considered on the preliminary step of the study. Next, a suitable configuration for feeding the ridges of antenna was chosen. The sinusoidal ridge taper is described in the next part of the paper. Finally, the simulations results of complete antenna are presented. Theoretical characteristics of reflection and antenna patterns are compared to the results of measurements showing acceptable accordance.

On the Approximation of the UWB Dipole Elliptical Arms With Stepped-Edge Polygon

A simple method of approximation of the elliptical patch with stepped-edge polygon is proposed as an introduction to wider studies over the planar ultrawideband (UWB) antennas. The general idea is to replace the elliptical patch with an equivalent polygonal patch, with minimum loss in the performance. The principles of the proposed method are presented in this letter, as well as the results of performed numerical studies and its experimental verification. A satisfying level of agreement of the parameters of the original antenna and its stepped-edge polygon version indicates that the proposed approximation can be applied without important loss of antenna performance.

Simulation-Driven Design of Microstrip Antenna Subarrays

A methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (e.g., a corporate network) on the subarray side lobe level and allows adjusting both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based optimization that produces designs meeting requirements imposed on both radiation and reflection at the cost of just a few simulations of the high-fidelity model of the structure of interest. Selected optimal designs of microstrip subarrays operating at 10 GHz have been manufactured and validated by measuring their radiation patterns and reflection coefficients.

Compact planar balun for the UWB dipole feeding network

Results of numerical simulations of a compact ultra wideband planar microstrip-to-coplanar strips balun is described in this paper. This circuit has been designed on the basis of configuration referenced in the literature. However, for application in the UWB antenna feeding networks it has been redesigned for the appropriate substrate. The designed balun has been loaded with a planar circular dipole, in order to validate its usefulness. Results obtained from full-wave simulations are presented in the paper. Calculated parameters of the balun and antenna show satisfactory level and predestine the circuit for fabrication.

Unified Design Procedure for Planar Dipoles Oriented on UWB Application

In the paper, the unifled design procedure for planar dipoles oriented on UWB application is proposed. The procedure leads to obtain a good matching characteristic of planar dipoles in UWB frequency band. The design process is split into two parts: the radiator and the balun design. The Radiator Quality Factor (RQF) is deflned as an evaluation suitability of planar radiators to be matched in UWB frequency band. Based on RQF, the optimal circular radiator is chosen, and the whole dipole antenna is designed. The general algorithm of antenna design is formulated and utilised in the planar dipole with elliptical arms project. Two antennas, with circular and elliptical arms, have been fabricated and measured in order to verify the design procedure. Both antennas are characterized by the re∞ection coe-cient less than i10dB from 2GHz up to 14GHz.