ABSTRACT This letter proposes an ultrawideband tightly coupled dipole rectenna array (TCDRA) for wireless power transfer (WPT). Compared to conventional designs of the same aperture area, the tightly coupled dipole array (TCDA) exhibits enhanced radiation efficiency and bandwidth, showing strong potential for WPT systems. Operating from 1 to 10 GHz, the proposed array employs a feeding structure combining a T‐junction and tapered baluns, which simplifies the design, ensures ultrawideband impedance matching, and reduces the need for subsequent power combining. The wide‐angle matching layer and resistive frequency selective surface (RFSS) are jointly optimized to minimize the RFSS impact on antenna efficiency. The ultrawideband rectifier, using a voltage‐doubling topology and an L‐type matching network, achieves a power conversion efficiency (PCE) above 50% from 0.03 to 10.37 GHz. A WPT system is built and tested at 1, 2.4, and 5.8 GHz, confirming that the proposed rectenna efficiently receives and converts RF energy over a wide frequency range, demonstrating suitability for diverse scenarios and complex electromagnetic environments.
ABSTRACT Full‐wave‐simulated array responses provide a data‐driven representation of the excitation‐to‐pattern mapping beyond the ideal array‐factor approximation. This letter presents a full‐wave‐data‐driven, surrogate‐assisted closed‐loop learning framework for excitation prediction from prescribed scan‐beam radiation patterns. A differentiable forward surrogate is first trained on a limited set of full‐wave‐derived excitation–pattern pairs and then used for efficient surrogate‐based data augmentation. During inverse training, the forward surrogate is frozen to reconstruct the radiation pattern from the predicted excitation, enabling pattern‐domain supervision on the main‐beam gain and sidelobe peak while retaining excitation‐domain supervision. For a 1 × 10 uniform linear array evaluated with 360‐point realized‐gain patterns, the proposed method achieves an average pattern root‐mean‐square error of 0.48 dB and a main‐beam pointing error of 0.14°, compared with 1.03 dB and 0.28° for a 1‐D ResNet‐18 baseline. Additional full‐wave‐level evaluation on 20 samples generated from the same array configuration and HFSS–MATLAB labeling workflow, but excluded from model training, shows lower mean RMSE and MSLL with comparable main‐beam pointing error. These results demonstrate an efficient data‐driven closed‐loop framework for excitation prediction in the considered full‐wave‐simulated array setting.
ABSTRACT This paper presents the design of a two‐antenna Multiple Input Multiple Output (MIMO) array specifically developed for laptop Wi‐Fi applications operating in the 2.4/5/6 GHz bands used by current Wi‐Fi 6E and Wi‐Fi 7 systems. The design features a remarkably small footprint for each individual antenna array element, measuring only 14.7 × 2.75 mm 2 . This compact design allows the proposed antenna to occupy minimal space on the bezel of laptop/notebook computers, aligning perfectly with the prevailing trend of narrow bezels and high screen‐to‐body ratios, especially for those requiring a frame height of approximately 3 mm. The antenna element itself employs an open‐loop structure with a shorting element, generating two modes that cover the entire Wi‐Fi 8 (2.4/5/6 GHz) bands. Experimental results demonstrate that each antenna element achieves an impressive efficiency of over 40%, while ensuring a standard isolation of 10 dB between adjacent antennas.
ABSTRACT A novel concept for a bandwidth‐scalable shared‐aperture antenna is proposed to achieve wideband dual circularly polarized (DCP) endfire radiation. The design synthesizes normal‐mode helix elements into a log‐periodic arrangement, effectively overcoming the conventional trade‐offs between polarization versatility and operating bandwidth. To validate the concept, a prototype employing quasi‐orthogonal counter‐wound helices has been optimized and fabricated. Each polarization, namely the left‐handed and the right‐handed circular polarization (LHCP and RHCP), is implemented by a sub‐array of thirteen series‐fed 3‐segment helical elements arranged in a log‐periodic configuration. Wideband DCP operation is realized through careful selection of double‐sided parallel stripline parameters and inter‐element spacing. To obtain high isolation between the two polarization modes, the element type is judiciously chosen, and the LHCP and RHCP elements are orthogonally oriented along their axes. Measured results show an overlapping bandwidth of 1.06 to 1.79 GHz (51.23%), achieving |S11| and |S22| below −10 dB and an axial ratio under 3 dB across the entire band. Furthermore, the bandwidth can be inherently scaled by adding more elements, offering strong potential for wireless applications such as electronic countermeasures and signal perception.
ABSTRACT Multiband fractal slot‐loaded patch antenna integrated with square Split Ring Resonators (SRR) has been designed to minimize cross polarization in E‐ as well as H‐planes. The slot dimension of 20 20 1.6 on the FR4 patch surface accompanied by a partial ground plane is generated through a microstrip line. The design and simulation of the projected antenna are achieved using HFSS 15. This design of antenna is found to achieve the desired multiband response due to fractal‐based slots along with square‐shaped SRRs. The presence of triangular slots in the patch reduces orthogonal E‐field components significantly, and consequently it leads to a decrement in the cross‐polarised emission corresponding to each resonating band. The operating bands obtained using this antenna are (3.51–3.68 GHz), (3.93–4.09 GHz), (4.33–4.57 GHz) and (6.71–7.99 GHz). The minimum cross‐ polarization level obtained using this antenna in the E and H planes are: −43.81 dB and −42.81 dB. The measured values of different parameters of the antenna are in agreement with the results obtained out of simulation.
