Journal of Electronic Research and Application

Design and Simulation of a Miniaturized Printed Wideband Antenna with a Gradual Radiator and Defected Ground

2026-07-07T12:32:44+08:00

To improve the integration capability and impedance matching of printed antennas for wideband wireless terminals, a miniaturized planar antenna with a gradual radiator and a defected partial ground is designed and verified by full-wave simulation. The antenna is implemented on an FR4 substrate of 31 mm x 18 mm x 1 mm and fed by a 50 Ohm microstrip line. A gradual, chamfered radiator with a top arc and T-shaped loading is combined with a partial ground containing a central slot and tapered edge, so that the forward and return current paths can be tuned simultaneously. The Driven Modal solver in Ansys HFSS is used to evaluate the reflection coefficient, field, and current distributions, and far-field radiation. The simulated S11 curve exhibits resonances near 3.3 GHz, 4.4-4.6 GHz, 7.7-8.0 GHz, and 13.0 GHz; the deepest resonance reaches about -35 dB, and the typical peak GainTotal is about 3.2 dBi. A parameter sweep of La from 0.6 mm to 0.8 mm shows little influence on the main resonances. The results indicate that the proposed structure provides a compact and feasible basis for multi-band or wideband terminal antennas.

Finite-Element Modeling and Analytical Validation of a Coaxial Cylindrical Capacitor Using Maxwell 2D

2026-07-07T12:32:45+08:00

To improve the reliability of capacitance prediction for compact coaxial components, a cylindrical capacitor with copper conductors and an air dielectric is modeled and verified by Ansys Maxwell 2D electrostatic simulation. The inner conductor radius is 0.6 mm, the outer conductor inner radius is 1.0 mm, and the outer conductor wall thickness is 0.2 mm. A 1 V potential is assigned to the inner conductor, while the outer conductor is grounded. Based on Gauss’s law, the analytical per-unit-length capacitance is calculated to be 108.9 pF/m. The finite-element model yields 107.4 pF/m, corresponding to a relative error of 1.38%. The simulated electric-field distribution is radially symmetric and reaches its maximum near the inner conductor, which agrees with the theoretical relation E(r) ∝ 1/r. The results show that Maxwell 2D can accurately reproduce the electrostatic behavior of coaxial capacitors and provide an efficient workflow for capacitance extraction, field visualization, and preliminary structural optimization.

Structural and Control System Design of an Automatic Cooking Robot

2026-07-07T12:32:46+08:00

With the rapid development of electronics, household kitchen appliances are gradually becoming intelligent. To improve the well‑being of office workers and address challenges such as limited time for cooking rice, this paper proposes the structure and control system of a cooking robot. The system uses an STM32 microcontroller as its core and integrates IoT and other new technologies to enable interaction among the smartphone, cloud, and the cooking robot. It supports remote control and monitoring via a mobile app, and on‑device monitoring of the operating status or the cooking curve through a touch screen. Experimental tests show that the robot can automatically complete a series of operations, including rice metering, rice washing, and rice cooking, making the system more user‑friendly and intelligent.

Architectural Design of RT-DETR-L for PCB Surface Defect Detection: A Systematic Comparison of Attention Mechanisms, Backbone Replacement, and Cross-Dataset Generalization

2026-07-07T12:32:46+08:00

Based on RT-DETR-L, this paper systematically compares five attention mechanisms (SE, CBAM, CA, ECA, and EMA) at the P3/P4/P5 outputs of the feature-pyramid neck under identical training conditions, and evaluates FasterNet backbone replacement and a P2 small-object detection head as complementary improvements. Experiments reveal a performance gap of up to 4.29 percentage points (CA: 93.04% to EMA: 97.33% in mAP₅₀), indicating that the choice of attention mechanism has a substantial impact on RT-DETR-type PCB detectors. EMA achieves the best mAP₅₀ (97.33%) and the highest mAP_50:95 (56.45%); ECA offers a competitive trade-off without increasing GFLOPs (96.69%); CA performs worst (93.04%), a 3.34 pp drop below the baseline, tentatively attributed to an architectural conflict with the AIFI encoder. FasterNet backbone replacement trades accuracy for efficiency (31% fewer parameters, 40% lower GFLOPs); and, when trained from scratch on the second dataset DeepPCB, the EMA variant again yields the largest gain (mAP₅₀89.33%, 4.83 pp over the baseline), showing that the improvement is not specific to a single dataset.