Meander structures are highly relevant in the Internet-of-Things (IoT) communication systems, their miniaturization remains as one of the key design issues. Meander structures allow to decrease the size of the IoT device, while maintaining the same operating parameters of the IoT device. Meander structures can also work as the delay systems, which can be used for the delay and synchronization of signals in IoT devices. The design procedure of the meander delay systems is time-consuming and cumbersome because of the complexity of the numerical and analytical methods employed during the design process. New methods, which will accelerate the synthesis procedure of the meander delay systems, should be investigated. This is especially relevant when the procedure of synthesis must be repeated many times until the appropriate configuration of the IoT device is found. We present the procedure of synthesis of the meander delay system using the Pareto-optimal multilayer perceptron network and multiple linear regression model with the M5 descriptor. The prediction results are compared with results, which were obtained using the commercial Sonnet software package and with the results of physical experiment. The difference between the experimentally achieved and predicted results did not exceed 1.53 %. Moreover, the prediction of parameters of the meander delay system allowed to speed up the procedure of synthesis multiple times from hours to only 2.3 s.INDEX TERMS Antenna arrays, antenna measurements, artificial neural networks, Internet of Things.

Rectangular microstrip structures are widely used in various microwave devices. Using the method of moments and principle of partial images, various techniques are developed to determine charge distribution in 2D models of microstrip structures (their cross-section). In this paper, a technique for calculating surface charge distribution and total capacitance of complex 3D rectangular microstrip structures is proposed using the mentioned method and principle. To demonstrate feasibility of the proposed technique, five rectangular microstrip structures were investigated. Obtained results are compared with the data published by other researchers. Total error is typically in 6-12% range.

Synthesis technique of six-conductor symmetrically coupled microstrip multiconductor line (MMCL), operating in a normal mode, is presented in this article. Results of the calculations acquired using the proposed mathematical model of an MMCL differ only by 3 % from the results acquired by other researchers. Examples of synthesis of six-conductor symmetrically coupled MMCL, operating in the even- and odd normal modes, are submitted in the article, also, dependences of parameters of these lines are investigated. It was established that the external conductors of an MMCL impart the most for ensuring the normal mode in an MMCL, and the organization of the internal conductors remains regular in this case. It is shown that parameters of the synthesized MMCL operating in the even normal mode depend in greater degree on the space between conductors, than MMCL operating in the odd normal mode. Ill. 7, bibl. 27, tabl. 2 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.110.4.285

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The algorithm for synthesis of the multi-tapped meander delay line (MTMDL) topology is proposed in this article. The algorithm is based on search of construction parameters of the MTMDL according to Monte Carlo method. Proposed algorithm was realized as software and tested on 14 nodes computer cluster. Experimental synthesis of lines has shown adequacy of the suggested algorithm. It has been shown that increasing number of nodes in the cluster, synthesis is executing faster and parallel part of the algorithm approaches to 90 percent of total algorithm. It is revealed that the maximal efficiency of the algorithm is achieved when the number of cluster nodes reaches the number of all issued synthesis processes.

The aim of this paper is to accelerate development and investigation of the delay systems. The computational time for investigation of particular design of delay system may take from several minutes up to several days. To achieve the required constructional parameters of the system, the iterative calculations usually should be repeated many times. In this paper, an artificial neural network is proposed to be used as the universal approximator for solving mathematical problems of delay system investigation instead of usual analytical and numerical techniques. The application of a multi-layer perceptron is proposed for approximation of solution space with discrete estimates, which were initially received by application of numerical techniques. Different structures of the multi-layer perceptron were tested for approximation. The difference between delay systems synthesis, which was estimated using numerical techniques and trained multi-layer perceptron did not exceed 5% for any of the six design parameter values. The execution time for estimating single delay system was reduced from 240 s to 20 ms. Such fast estimation of design parameters enables performing delay system analysis and design in real time, preserving time for structure visualization in 3D or virtual reality environment.

Inhomogeneities of the electromagnetic field are observed at the edges of the electrodynamic delay systems which are designed based on the concept of periodic multiconductor line. The inhomogeneity manifests itself as a non-uniformity of the characteristic impedance and the effective permittivity of the multiconductor line consisting of a finite number of conductors. The influence of non-uniformity of impedance and effective permittivity of the multiconductor microstrip line on the frequency responses and characteristics of meander delay lines is studied in this paper. It is shown that matching characteristic impedance and effective permittivity of the multiconductor line the bandwidth of the delay line can be extended and delay time increased preserving its dimensions. Index Terms-effective permittivity, impedance matching, meander delay lines, method of multiconductor line, mode matching. Two kinds of non-uniformity appear in real MMDLs based on the mathematical model of the MCMLs: − non-uniformity of characteristic impedance Z i ≠ Z j , − non-uniformity of effective permittivity ε r eff i ≠ ε r eff j , where i and j are numbers of conductors of the MMDL, and

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