Rotatable-Antenna-Aided Near-Field Wideband Integrated Sensing and Communication System: Hybrid Beamforming Design

XU Hongbo; MO Minghui; XIN Wei; WANG Shuli; WANG Ji; LI Xingwang; ZHENG Le

doi:10.11999/JEIT260023

Article Contents

Article Navigation > Journal of Electronics & Information Technology > 2025 >

XU Hongbo, MO Minghui, XIN Wei, WANG Shuli, WANG Ji, LI Xingwang, ZHENG Le. Rotatable-Antenna-Aided Near-Field Wideband Integrated Sensing and Communication System: Hybrid Beamforming Design[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260023

Citation:

XU Hongbo, MO Minghui, XIN Wei, WANG Shuli, WANG Ji, LI Xingwang, ZHENG Le. Rotatable-Antenna-Aided Near-Field Wideband Integrated Sensing and Communication System: Hybrid Beamforming Design[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260023

Citation:

XU Hongbo, MO Minghui, XIN Wei, WANG Shuli, WANG Ji, LI Xingwang, ZHENG Le. Rotatable-Antenna-Aided Near-Field Wideband Integrated Sensing and Communication System: Hybrid Beamforming Design[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260023

PDF( 1924 KB)

Rotatable-Antenna-Aided Near-Field Wideband Integrated Sensing and Communication System: Hybrid Beamforming Design

doi: 10.11999/JEIT260023 cstr: 32379.14.JEIT260023

1.
College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
2.
China Ship Research and Development Academy, Beijing 100101, China
3.
School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo 454003, China
4.
School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China

Funds: National Natural Science Foundation of China (62571182)

Received Date: 2026-01-07
Accepted Date: 2026-03-16
Rev Recd Date: 2026-03-16

Available Online: 2026-04-06

Abstract

Abstract

Objective Near-field wideband Integrated Sensing and Communication (ISAC) systems face two main challenges: pronounced near-field effects and wideband beam splitting. These effects reduce communication throughput and sensing reliability, particularly when fixed-orientation antenna arrays and phase-shifter-based beamforming architectures are used. Because such architectures provide limited spatial adaptability and frequency-independent phase control, the spatial-frequency degrees of freedom available in near-field wideband channels cannot be fully used. To address this issue, a Rotatable-Antenna-assisted near-field wideband ISAC architecture is investigated to improve the system sum rate under sensing constraints. Methods A near-field wideband ISAC architecture assisted by Rotatable Antennas (RAs) is proposed. By allowing the antenna boresight direction to be adjusted mechanically or electronically, additional angular degrees of freedom are provided at the element level, which enables more flexible spatial coverage and more accurate energy focusing. A True Time Delay (TTD)-based hybrid beamforming architecture is further adopted to provide frequency-dependent phase shifts and compensate for the frequency-independent property of conventional phase shifters. Consistent beam focusing across subcarriers is thus maintained, and wideband beam splitting is effectively suppressed. Based on a spherical-wave near-field channel model that incorporates propagation distance, angular information, and the orientation gain of RAs, a joint optimization problem is formulated to maximize the system sum rate under transmit power constraints, sensing power thresholds, and antenna rotation constraints. Because the resulting problem is highly non-convex, a Penalty-Based Fully Digital Approximation (PBFDA) algorithm is developed. In each iteration, the RA orientations are first optimized by Particle Swarm Optimization (PSO) to improve the weighted channel gain. Then, with the antenna orientations fixed, a reduced-dimensional formulation with Successive Convex Approximation (SCA) is used to solve the fully digital beamforming problem. Finally, a manifold-based Block Coordinate Descent (BCD) algorithm is used to jointly optimize the analog beamformer, digital beamformer, and TTD units, so that the hybrid beamforming solution gradually approaches the fully digital solution (Algorithm 1–Algorithm 4). Results and Discussions Simulation results verify the effectiveness of the proposed RA-assisted near-field wideband ISAC framework. The proposed PBFDA algorithm converges monotonically within a limited number of iterations, which confirms its numerical stability and efficiency (Fig. 2). Compared with fixed-antenna architectures, the proposed RA-assisted scheme achieves a clear improvement in system sum rate under the same transmit power constraint (Fig. 3). When the system bandwidth increases, the spectral efficiency of TTD-based hybrid beamforming decreases because the limited number of TTD units and the restricted maximum delay weaken frequency-dependent compensation and aggravate beam splitting. By contrast, the optimal fully digital beamforming scheme maintains nearly unchanged spectral efficiency because each subcarrier can be controlled accurately (Fig. 4). When the sensing power threshold increases, the achievable sum rate decreases for all schemes, which reflects the trade-off between communication and sensing. The proposed method, however, consistently outperforms the benchmark schemes (Fig. 5). The effects of antenna number, antenna directivity factor, and maximum rotation angle are also evaluated. Spectral efficiency increases with the number of antennas because of the higher array gain (Fig. 6). As the antenna directivity factor increases, the RA-assisted system attains further gains through adaptive orientation, whereas fixed-orientation and isotropic schemes degrade (Fig. 7). A larger allowable rotation range also provides greater spatial alignment flexibility and further improves system performance (Fig. 8). Overall, the proposed architecture improves near-field energy focusing and achieves performance close to that of fully digital beamforming with lower hardware complexity. Conclusions A Rotatable-Antenna-assisted near-field wideband ISAC system with a TTD-based fully connected hybrid beamforming architecture is investigated. By jointly using antenna rotation and true time delay, the proposed framework effectively mitigates near-field effects and wideband beam splitting. The developed PBFDA algorithm solves the resulting highly non-convex optimization problem efficiently. Numerical results show that the proposed scheme significantly improves the system sum rate under sensing constraints and approaches the performance of fully digital beamforming, which supports its use in near-field wideband ISAC systems.
- Integrated Sensing and Communication (ISAC),
- Rotatable Antenna (RA),
- True Time Delay (TTD),
- Hybrid beamforming,
- Near-field communication

FullText(HTML)

References(19)

References

[1]	SHAMEER M and RUTRAVIGNESHWARAN P. A comprehensive survey of IoT security, trust models, and cloud-based solutions for ensuring a secure connected future[C]. The 2024 International Conference on Computing and Intelligent Reality Technologies (ICCIRT), Coimbatore, India, 2024: 11–16. doi: 10.1109/ICCIRT59484.2024.10921791.
[2]	QU Kaiqian, GUO Shuaishuai, SAEED N, et al. Near-field integrated sensing and communication: Performance analysis and beamforming design[J]. IEEE Open Journal of the Communications Society, 2024, 5: 6353–6366. doi: 10.1109/OJCOMS.2024.3470844.
[3]	林粤伟, 张奇勋, 尉志青, 等. 通信感知一体化硬件设计——现状与展望[J]. 电子与信息学报, 2025, 47(1): 1–21. doi: 10.11999/JEIT240012. LIN Yuewei, ZHANG Qixun, WEI Zhiqing, et al. Status and prospect of hardware design on integrated sensing and communication[J]. Journal of Electronics & Information Technology, 2025, 47(1): 1–21. doi: 10.11999/JEIT240012.
[4]	WANG Xiangrong, ZHAI Weitong, WANG Xianghua, et al. Wideband near-field integrated sensing and communications: A hybrid precoding perspective[J]. IEEE Signal Processing Magazine, 2025, 42(1): 88–105. doi: 10.1109/MSP.2024.3496396.
[5]	褚宏云, 杨梦瑶, 黄航, 等. 混合智能反射面辅助的通信感知一体化: 高能效波束成形设计[J]. 电子与信息学报, 2024, 46(6): 2462–2469. doi: 10.11999/JEIT230699. CHU Hongyun, YANG Mengyao, HUANG Hang, et al. Hybrid reconfigurable intelligent surface assisted integrated sensing and communication: Energy efficient beamforming design[J]. Journal of Electronics & Information Technology, 2024, 46(6): 2462–2469. doi: 10.11999/JEIT230699.
[6]	WANG Xiangrong, ZHAI Weitong, WANG Xianghua, et al. Wideband near-field integrated sensing and communication with sparse transceiver design[J]. IEEE Journal of Selected Topics in Signal Processing, 2024, 18(4): 662–677. doi: 10.1109/JSTSP.2024.3394970.
[7]	张若愚, 任红, 陈光毅, 等. MIMO雷达通信一体化: 波束图增益最大化波束成形设计[J]. 电子与信息学报, 2025, 47(3): 687–695. doi: 10.11999/JEIT240631. ZHANG Ruoyu, REN Hong, CHEN Guangyi, et al. MIMO dual-functional radar-communication: Beampattern gain maximization beamforming design[J]. Journal of Electronics & Information Technology, 2025, 47(3): 687–695. doi: 10.11999/JEIT240631.
[8]	GAO Zhen, WAN Ziwei, ZHENG Dezhi, et al. Integrated sensing and communication with mmWave massive MIMO: A compressed sampling perspective[J]. IEEE Transactions on Wireless Communications, 2023, 22(3): 1745–1762. doi: 10.1109/TWC.2022.3206614.
[9]	CONG Jiayi, YOU Changsheng, LI Jiapeng, et al. Near-field integrated sensing and communication: Opportunities and challenges[J]. IEEE Wireless Communications, 2024, 31(6): 162–169. doi: 10.1109/MWC.002.2400033.
[10]	WANG Zhaolin, MU Xidong, and LIU Yuanwei. Beamfocusing optimization for near-field wideband multi-user communications[J]. IEEE Transactions on Communications, 2025, 73(1): 555–572. doi: 10.1109/TCOMM.2024.3424244.
[11]	WANG Zhaolin, MU Xidong, LIU Yuanwei, et al. TTD configurations for near-field beamforming: Parallel, serial, or hybrid?[J]. IEEE Transactions on Communications, 2024, 72(6): 3783–3799. doi: 10.1109/TCOMM.2024.3370832.
[12]	ELBIR A M, CELIK A, and ELTAWIL A M. Near-field hybrid beamforming for terahertz-band integrated sensing and communications[C]. The 2023 IEEE Globecom Workshops (GC Wkshps), Kuala Lumpur, Malaysia, 2023: 1117–1122. doi: 10.1109/GCWkshps58843.2023.10464709.
[13]	LUO Hongliang, GAO Feifei, YUAN Wanmai, et al. Beam squint assisted user localization in near-field integrated sensing and communications systems[J]. IEEE Transactions on Wireless Communications, 2024, 23(5): 4504–4517. doi: 10.1109/TWC.2023.3319474.
[14]	NEW W K, WONG K K, XU Hao, et al. A tutorial on fluid antenna system for 6G networks: Encompassing communication theory, optimization methods and hardware designs[J]. IEEE Communications Surveys & Tutorials, 2025, 27(4): 2325–2377. doi: 10.1109/COMST.2024.3498855.
[15]	WONG K K, SHOJAEIFARD A, TONG K F, et al. Fluid antenna systems[J]. IEEE Transactions on Wireless Communications, 2021, 20(3): 1950–1962. doi: 10.1109/TWC.2020.3037595.
[16]	ZHU Lipeng, MA Wenyan, and ZHANG Rui. Modeling and performance analysis for movable antenna enabled wireless communications[J]. IEEE Transactions on Wireless Communications, 2024, 23(6): 6234–6250. doi: 10.1109/TWC.2023.3330887.
[17]	WU Qingjie, ZHENG Beixiong, MA Tiantian, et al. Modeling and optimization for rotatable antenna enabled wireless communication[C]. The ICC 2025-IEEE International Conference on Communications, Montreal, Canada, 2025: 1055–1060. doi: 10.1109/ICC52391.2025.11161853.
[18]	LIU Yuanwei, WANG Zhaolin, XU Jiaqi, et al. Near-field communications: A tutorial review[J]. IEEE Open Journal of the Communications Society, 2023, 4: 1999–2049. doi: 10.1109/OJCOMS.2023.3305583.
[19]	HE Xiuli, XU Hongbo, ZHANG Guoping, et al. RIS-assisted joint near-field channel estimation and beamforming design based on deep unfolding[J]. IEEE Transactions on Vehicular Technology, 2026, 75(3): 4411–4423. doi: 10.1109/TVT.2025.3612046.