We present a general approach for antenna design and optimization based on consensus of results from a number of independently trained deep neural networks (DNNs). The aim of using the consensus is to reduce the uncertainty of results from a single DNN. The approach leads to several orders of magnitude faster antenna optimization and design compared to the optimization based on a full-wave solver and allows a compromise between the analysis speed and its accuracy. The used DNNs are multilayer perceptrons (MLP) with multiple fully connected hidden layers. As an example, we consider the Yagi–Uda antenna with four design parameters and optimize it for the maximal forward gain. The training of neural networks is done on datasets of several sizes, up to 1 million antenna samples. The samples are generated either randomly or at a uniform grid over the design space using the method of moments.

In order to provide a constant and complete operational picture of the maritime situation in the Exclusive Economic Zone (EEZ) at over the horizon (OTH) distances, a network of high frequency surface-wave-radars (HFSWR) slowly becomes a necessity. Since each HFSWR in the network tracks all the targets it detects independently of other radars in the network, there will be situations where multiple tracks are formed for a single vessel. The algorithm proposed in this paper utilizes radar tracks obtained from individual HFSWRs which are already processed by the multi-target tracking algorithm at the single radar level, and fuses them into a unique data stream. In this way, the data obtained from multiple HFSWRs originating from the very same target are weighted and combined into a single track. Moreover, the weighting approach significantly reduces inaccuracy. The algorithm is designed, implemented, and tested in a real working environment. The testing environment is located in the Gulf of Guinea and includes a network of two HFSWRs. In order to validate the algorithm outputs, the position of the vessels was calculated by the algorithm and compared with the positions obtained from several coastal sites, with LAIS receivers and SAIS data provided by a SAIS provider.

Christoffel–Darboux formula for Chebyshev continual orthogonal polynomials of the first kind is proposed to find a mathematical solution of approximation problem of a one-dimensional (1D) filter function in the z domain. Such an approach allows for the generation of a linear phase selective 1D low-pass digital finite impulse response (FIR) filter function in compact explicit form by using an analytical method. A new difference equation and structure of corresponding linear phase 1D low-pass digital FIR filter are given here. As an example, one extremely economic 1D FIR filter (with four adders and without multipliers) is designed by the proposed technique and its characteristics are presented. Global Christoffel–Darboux formula for orthonormal Chebyshev polynomials of the first kind and for two independent variables for generating linear phase symmetric two-dimensional (2D) FIR digital filter functions in a compact explicit representative form, by using an analytical method, is proposed in this paper. The formula can be most directly applied for mathematically solving the approximation problem of a filter function of even and odd order. Examples of a new class of extremely economic linear phase symmetric selective 2D FIR digital filters obtained by the proposed approximation technique are presented.

In this work, a novel design of patch antenna with two symmetrical slits and two closely spaced resonances is proposed. Novel patch antenna demonstrates a great flexibility in impedances adjustment at both resonances that is of a great importance in the design of series fed antenna arrays with a large number of radiating elements. Printed antenna with two linear arrays consisting of 16 serially fed patches is designed and fabricated. Measured results agree very well with simulations. Antenna operation frequency range is 15.6–17.3 GHz that is 10.3% of a relative bandwidth. The measured antenna gain is 19.5 dBi with a small variation of 1.2 dB within the whole operating bandwidth, sidelobe levels are below −22 dB in H-plane and −11.5 dB in E-plane. Half power beamwidth is less than 8° and 40°, in H-and E-planes, respectively. Antenna array exhibits the enhanced impedance and radiation bandwidth in comparison with similar antenna structures and is very suitable for various radar applications, notably for compact, low-cost frequency-modulated continuous wave systems.

This article describes an implementation of a compact wire model into the three-dimensional transmission-line matrix (TLM) cylindrical mesh for the purpose of an efficient analysis of probe-coupled cylindrical microwave cavity devices. Because of a cylindrical grid structure and empirical nature of the compact model, this implementation has to take into account a change of wire model parameters with a variable cross section of the TLM nodes through which a wire conductor passes. The model accuracy has been experimentally verified and compared with the corresponding results reached by the TLM method based on a rectangular grid in order to consider its advantages. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.