2023/1
Browse
Recent Submissions
- ItemSAMPLE Dataset Objects Classification Using Deep Learning Algorithms(Společnost pro radioelektronické inženýrství, 2023-04) Turcanik, M.; Perdoch, J.The main topic of the article is automatic target classification of the synthetic aperture radar images based on the dataset composed of measured and synthetic data. The original contribution of the authors is their own topology of the convolutional neural network (CNN) with 1, 2, 3, and 4 tiers. The original convolutional neural network is used to classify radar images from the Synthetic And Measured Paired and Labeled Experiment (SAMPLE) dataset which consists of SAR imagery from publicly available datasets and well-matched synthetic data. The presented topologies of the CNN with 1, 2, 3, and 4 tiers were analyzed in 3 different scenarios: trained on the basis of real measured data and tested by synthetic data, trained on the basis of synthetic data, and tested by real measured data, and in the last case training and testing sets were formed by combining real measured and synthetic data. Based on the results of testing we could not use the proposed convolutional neural network trained with real measured data to classify synthetic radar images and vice versa (the 1st and the 2nd scenarios). The only last scenario with a combination of real measured and synthetic data in the training, validation, and testing data sets generates excellent results. The authors also present some confusion matrices, which can explain the reasons for the misclassification of radar images of military equipment. Comparing achieved results with another SAMPLE dataset classification results we can prove the usability of proposed and tested CNN structures for automatic target classification of the synthetic aperture radar images. The classification accuracy of the original convolutional network is 96.1%, which is better than the results of the other research so far.
- ItemQuasistatic Resonators Based Triple-Mode Notched Microstrip Bandpass Filter(Společnost pro radioelektronické inženýrství, 2023-04) Hugar, S. I.; Baligar, J. S.; Dakulagi, V.; Vanitha, K. M.This article discusses new approach for design and development of triple-mode notched microstrip bandpass filter based on quasistatic resonators(QR). The proposed approach is composed of two Quasistatic resonant elements; Horizontal plane Split ring resonator (HP-SRR), Vertical plane split ring resonator (VP-SRR) and a single asymmetric step impedance resonator (A-SIR) with parallel coupled feed structure. An additional attenuation pole realized by VP-SRR in desired passband, tunes the dual-mode response to triple mode and enhances the 3dB bandwidth without changing the dimensions of basic the filter cell. The HP-SRR realizes a notch at WiMAX band (IEEE 802.11a lower band) in the desired passband. Further by changing the impedance of VP-SRR and HP-SRR both the location of additional attenuation pole frequency and notch band can be controlled. The proposed approach results in compact, notched wideband, filter design.
- Item180 nm CMOS Cold-Start Energy-Aware Switching Circuit for Energy Management in WPT Receiver(Společnost pro radioelektronické inženýrství, 2023-04) Vinko, D.; Grgic, K.; Bilandzija, D.Modern electronic devices offer high level performance at low power consumption. This opens a possibility to have battery-less electronic devices. Energy harvesting and wireless power transfer are popular methods to power such devices. Both methods require energy management. The focus of this paper is on energy management for receiver circuit in a wireless power transfer system. More specifically, the paper focuses on a cold-start energy-aware switching circuit which is a key building block of energy management in WPT receiver. Proposed integrated circuit is designed to operate in discontinuous mode and can supply power to load circuits which require higher voltage and current levels than available from the WPT receiver. Unlike most similar solutions who are fully integrated, the proposed integrated circuit uses two external trimmer resistors to adjust required voltage levels and the power consumption. External trimmer resistors also allow to compensate for the process variations of IC fabrication. Developed circuit is fabricated in 180 nm TSMC CMOS technology and evaluated through laboratory measurement. Cold-start functionality and energy-aware switching are verified through standalone measurements and measurements with WSN node powered through developed circuit. The power consumption of cold-start switching circuit is measured less than 1 µW.
- ItemDesign and Fabrication of Birdcage Resonators for Low-pressure Plasma Excitation(Společnost pro radioelektronické inženýrství, 2023-04) Jurik, K.; Stary, J.; Drexler, P.This paper presents a design, analysis and optimization of birdcage resonators employed in a novel radiofrequency plasma source. Three resonators were simulated and fabricated. The resonators differ in their design and in the different materials of used dielectric – polyimide and polytetrafluorethylene (PTFE). The resonance frequency of fabricated samples possesses a maximal error of 2.2 % compared to the simulated values. The performance in plasma excitation is related to the electrical parameters, while the best performing resonator (PTFE-based) exhibits the maximum real impedance of 644.3 Ω at the resonance frequency and the 799.5 V/m electric field strength. This resonator shows the best power efficiency in a plasma ignition experiment. The resonator ignited the discharge at ca. 1 Pa of ambient air atmosphere with only 0.34 W of input radiofrequency power.
- ItemMoving Target Simulation of Multi-Band Radar Based on Doppler Frequency Signal Generation Technology(Společnost pro radioelektronické inženýrství, 2023-04) Hao, J.; Wang, X.; Sun, X.; Gao, H.; Zou, L.This paper proposes a corner reflector and Luneburg ball reflector group. The omnidirectional radar cross-sectional (RCS) distribution characteristics of a fighter are simulated using the sharp and smooth RCS distribution features of the corner and the Luneburg ball reflectors, respectively. A new type of Doppler signal generation principle is proposed to design a Doppler frequency simulator to transmit frequency signals by connecting in parallel with the metal layer of the corner reflector and the Luneburg sphere ball, and then transmit through their other end. The existing radar target aircraft cannot simulate the RCS and speed of the targets that are less than 0.005 m2 by enhancing the echo intensity of the target location, which makes it impossible for the military to conduct practice drills and evaluate the effectiveness of the air defense systems. The experimental results show that the Doppler frequency simulator successfully simulates the target speed of 0-80 km/h and when the speed is greater than 20 km/h, the error of the simulation frequency is less than 1.5%. The proposed method can provide guidance and a theoretical basis for simulating the speed of various types of aircraft in future work.