Design of multi-layer radar absorber material (MRAM) is a multi-objective problem for minimizing total reflection (TR) together with the total thickness (TT) by selecting optimum variables such as the material type for each layer from a material database and determining the thickness of each layer. In this paper, five-layer broadband and wide-incident-angle MRAMs (BWM) at the most important radar bands of 0.2–2, 2–8, 8–12, 12–18, and 2–18 GHz are optimally designed through an implemented EM model by taking into account of the incident wave angle with TE and TM polarizations using surrogate-based optimization (SbO) integrated with Pareto front technique. The MRAMs are optimized for the multi-objective functions of the TR and TT by ensuring the tradeoff for mean oblique incident between 0° and 40° with a mean of TE and TM. The BWMs have, respectively, the TT and TR of 3.38 mm, −27.83 dB; 2.13 mm, −22.31 dB; 1.11 mm, −25.24 dB; 1.0426 mm, −25.47 dB; and 2.69 mm, −18.88 dB. They are elaborately compared with those in the literature. Therefore, the proposed BWMs are the most optimal designs with regard to the TR and TT, thanks to the computational fast and powerful multi-objective SbO and Pareto front.

Multi-Objective Design of Multi-Layer Radar Absorber Using Surrogate-Based Optimization

Strong circular dichroism in absorption in the near-infrared wavelength range is realized by designing binary-pattern chiral plasmonic metasurfaces via the micro-genetic algorithm optimization method. The influence of geometric parameter modifications in the binary-pattern nanostructures on the circular dichroism performance is studied. The strong circular dichroism in absorption is attributed to the simultaneous excitation and field interference of the resonant modes with relative phase delay under linearly polarized incident light. This work provides a universal design method toward the on-demand properties of chiral metasurfaces, which paves the way for future applications in chemical and biological sensing, chiral imaging and spectroscopy.

https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=5868&context=mec_aereng_facwork

Strong circular dichroism in chiral plasmonic metasurfaces optimized by micro-genetic algorithm.

Broadband binary-pattern metasurface absorbers are designed and demonstrated in the mid-infrared wavelength range through the micro-genetic algorithm. The tungsten-based metasurface absorbers with the optimized binary-pattern nanostructures exhibit broadband near-perfect absorption due to the multiple plasmonic resonances supported within the unit cell. Furthermore, the influence of minor pixel modifications in the optimized binary-pattern nanostructures on the absorption performance is investigated in the experiment. This Letter presents a promising approach to design and optimize complex optical nanostructures with the desired properties for metamaterial and metasurface applications.

Broadband infrared binary-pattern metasurface absorbers with micro-genetic algorithm optimization.

In general, cost function for optimal design of multilayer microwave absorbers found in literature had not taken account of normal and oblique incidence (TE & TM polarization) of wave in optimization problem which leads to sub-optimal design limited only for particular incidence of wave, either a normal or oblique incidence of wave at a time. To overcome the above problem, this paper focuses on optimal design of multilayer absorbers through a proposed cost function which can work for both normal and oblique incidence of wave up to wide angle of incidence (0–60°) with TE & TM polarization simultaneously. The objective of this optimization process is to reduce maximum reflection coefficient of the absorber by selecting suitable layers of materials from the available database in literature and optimize the total thickness to possible minimum level. Five models of four layer multilayer absorbers are proposed using WDO algorithm for different frequency bands (ranging from 2 – 8, 8 – 12, 12 – 18, 2 – 12 and 2 – 18 GHz). A detailed analysis are done and it shows that the application of WDO yields improved numerical results in terms of thickness and oblique incidence of wave as compared with the earlier reported results.

A novel approach for optimal design of multilayer wideband microwave absorber using wind driven optimization technique

The design of multilayer radar absorber (MRA) has become quite popular in the last quarter century, and many studies have been presented to optimize different MRAs. In these studies, the number of layers (NL) has been predetermined, and thicknesses of the layers have been defined in the same parametric sequence. However, according to the type of objective function, the NL and thicknesses may vary, so this initial predetermination may prevent the discovery of the best overall solution. In this study, a double-stage artificial bee colony (DS-ABC) algorithm which evaluates the number and sequence of layers separately from thicknesses is proposed for the optimum design of MRA. Thus, the sequence and thickness of the MRAs are optimized to minimize the reflection coefficient and the total thickness for the desired frequency ranges (2–18 GHz), angles of incidence (0°–40°), and polarizations [transverse electric (TE)–transverse magnetic (TM)]. For the MRA designs, 16 predefined materials and recently published 21 up-to-date materials are used. The designed MRAs are compared with those optimized by other algorithms existing in the literature. The results show that the DS-ABC algorithm is more effective than other conventional metaheuristic search algorithms to find the optimal layer sequence and corresponding thicknesses.

Determination of Optimal Layer Sequence and Thickness for Broadband Multilayer Absorber Design Using Double-Stage Artificial Bee Colony Algorithm

Microwave absorbers find a plethora of applications in the modern-day military and civil industries. This paper compares the performances of different variations of the Particle Swarm Optimization (PSO) algorithm to obtain optimal designs for multilayer microwave absorber over different frequency ranges, angles of incidence and polarizations. The goal of this optimization is to minimize maximum overall reflection coefficient of the absorber by choosing suitable layers of materials from a predefined database and simultaneously make the overall thickness the least practically possible. Numerical optimal results for each variation of the PSO are presented and the best results are compared with those existing in literature.

/pdf/particle-swarm-optimization-for-optimal-design-of-broadband-4oyw3bgzwl.pdf

Particle Swarm Optimization for Optimal Design of Broadband Multilayer Microwave Absorber for Wide Angle of Incidence

Microwave absorbers have emerged as an indispensable industrial apparatus in today’s world, owing to their multitude of uses, both civil as well as military. This paper focuses on the use of three evolutionary algorithms, namely, particle swarm optimization, bat algorithm and cuckoo search algorithm for the purpose of obtaining optimal designs of seven layer microwave absorbers over a wide frequency range, and both cases of normal and oblique incidence. The resultant optimal designs are compared in terms of maximum reflection coefficient and total thickness with those presented in existing literature.

Comparison of Evolutionary Algorithms for Optimal Design of Broadband Multilayer Microwave Absorber for Normal and Oblique Incidence

Spiral coil-based inductor–capacitor (LC) resonant sensors have seen many applications in agriculture, healthcare, biomanufacturing, and consumer electronics. Traditional techniques to interrogate such sensors using vector network analyzers (VNAs) are expensive and often not portable, whereas custom readouts suffer from high cost, low range of usable interrogation distances, or low frequency range. This article proposes a new simple, low-cost, and portable readout design based on the technique of coherent demodulation. A complete theoretical analysis examining how the interrogation distance is related to other circuit parameters is presented. Finally, a complete readout system was implemented using printed circuit board technology and commercially available off-the-shelf components. The system operates between 1 and 100 MHz and the fabricated system consumes 1.26 W. Measurements show that the system operates reliably and repeatably with interrogation distances up to 5 cm.

Low-Cost Portable Readout System Design for Inductively Coupled Resonant Sensors

Classroom to Workplace: Knowledge and Skills Learned by Recently Hired Aerospace Engineers

Most modern-day communication systems require the use of baluns to interface between differential and single-ended components. Using an example of a concurrent dual-band switch-mode push-pull power amplifier, this paper establishes that distributed baluns designed using traditional strategies, focusing solely on a balun's center frequency, lead to reduced efficiency due to the imperfect termination of the intermodulation components of their common mode signal. For solving this problem, a wide-band mixed-mode S-parameter analysis is employed to derive the common mode termination requirements of distributed baluns for concurrent dual-band operation; based on which, a generalized design procedure is developed to modify traditional balun designs. The modification provides the required termination to prevent common mode power loss while preserving the balun's performance in terms of input port matching, insertion loss, and amplitude and phase balance. The newly developed theory is tested by designing a modified concurrent dual-band tapped stepped-impedance balun. Measurement results are provided to validate the feasibility of the approach.

Subhanwit Roy

Papers

Particle Swarm Optimization for Optimal Design of Broadband Multilayer Microwave Absorber for Wide Angle of Incidence

Comparison of Evolutionary Algorithms for Optimal Design of Broadband Multilayer Microwave Absorber for Normal and Oblique Incidence

Low-Cost Portable Readout System Design for Inductively Coupled Resonant Sensors

Classroom to Workplace: Knowledge and Skills Learned by Recently Hired Aerospace Engineers

Analysis and Design of Concurrent Dual-band Distributed Baluns