In this study, a new spiral dual-band antenna integrated with an optical system for a small CubeSat spacecraft was proposed. It is challenging to design an antenna with a limited space on a CubeSat platform. To improve the space utilization, an antenna was designed based on the concept of not occupying the sides of the CubeSat. A feature of the proposed antenna system is its compactness, dual-band operation in the L- and S-bands, and possibility of integration with spacecraft cameras. As a result of the study, reflection coefficients of −18 dB and −23 dB and gain of 6.8 dBi and 7.4 dBi, respectively, were achieved at resonant frequencies of 1.7 GHz and 2.45 GHz. The conical shape of the spiral antenna allows the optical system to increase the coverage area, and a simple deployment system with feedback ensures the mission safety. These properties make the proposed antenna suitable for CubeSat systems.

Automatic Modulation Classification (AMC) is an essential technology that is widely applied into various communications scenarios. In recent years, many Machine Learning and Deep-Learning methods have been introduced into AMC, and a lot of them apply different approaches to eliminate interference in complex Multiple-Input and Multiple-Output (MIMO) signals and improve classification performance. However, in practical communication systems, the perfect elimination of MIMO signal interference is impossible, and therefore classification performance suffers. In this paper, we propose a new AMC algorithm for MIMO system based on mutual information (MI) features extraction, which does not require a large amount of training data and the elimination of MIMO signal interference. In this approach, features based on mutual information are extracted using In-Phase and Quadrature (IQ) constellation diagrams of MIMO signals, which have not been explored previously. Our method can be effective since mutual information considers the interdependencies among variables and measures how much information about one variable reduces uncertainty about another, providing a valuable perspective for extracting higher-level and interesting features from the data. The effectiveness of our method is evaluated on several model and real-world datasets, and its applicability is proven.

Division remains one of the most computationally demanding operations in digital arithmetic. Traditional algorithms, such as restoring, non-restoring, and SRT (Sweeney–Robertson–Tocher) division, are limited by sequential dependencies that reduce throughput in hardware implementations. To overcome these constraints, this work proposes a pipelined integer divider architecture that employs precomputed divisor multiples and comparator-based logic to eliminate the need for full binary adders in the quotient selection stages. The proposed design consists of a three-stage pipeline, where each stage compares the shifted partial remainder with stored multiples of the divisor (B, 2B, 3B) to generate two quotient bits per clock cycle. This approach achieves a 2× reduction in the number of computation stages compared with conventional radix-2 dividers and ensures continuous operation after an initial pipeline latency. The architecture was described in Verilog hardware description language (HDL) and implemented on a Xilinx Artix-7 (XC7A100T-1CSG324C) field-programmable gate array (FPGA) using the Xilinx ISE Design Suite 14.4. Post-synthesis simulation confirmed correct quotient and remainder generation with a maximum operating frequency of 208 MHz. The implementation occupied less than 0.3% the look-up table (LUT) resources, achieving over a twofold performance improvement compared with a non-pipelined baseline. These results demonstrate that the proposed divider provides an efficient trade-off between speed and hardware cost, making it suitable for digital signal processing and embedded computation systems.

This article discusses the possibilities of using fractal antenna systems in wireless communication systems, their features and the main advantages of using them. The presence of the property of self-similarity of fractal structures allows them to be implemented in the creation of broadband and multiband antennas. Therefore, today the capabilities of a fractal antenna are widely studied in wireless communication systems such as 5G, 4G (LTE), Bluetooth, WLAN, WiMAX, GPS and others. The article also presents the main characteristics of fractal antennas and the practical implementation of the antenna model in the Ansys HFSS program. Simulation results, such as S11-parameter, radiation pattern and gain for MIMO patch antenna based on anisotropic fractal, and L, S band patch antenna for CubeSat nanosatellites are presented.