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Xianbin Yu

Publications and source records attributed to Xianbin Yu.

8 recordsLinked to original sources

Low Complexity Kolmogorov-Arnold Network-based DPD for Analog RoF Fronthaul

This paper proposes and demonstrates experimentally for the first time a Kolmogorov-Arnold Network (KAN)-based digital predistortion (DPD) model, named envelope time-delay KAN (ETDKAN), for mitigating nonlinear distortions in analog radio-over-fiber (A-RoF) systems. The ETDKAN model incorporates physical constraints of radio-frequency (RF) nonlinear devices and, through KAN symbolization, achieves a significant reduction in computational complexity while improving interpretability. The proposed model is numerically implemented and optimized alongside multilayer perceptron (MLP) and memory-polynomial-based DPDs. Results show that the resulting symbolic ETDKAN (symbETDKAN) attains ACLR and EVM performance comparable to neural network-based models, while maintaining a computational complexity close to that of memory polynomials. Experimental validation using an A-RoF system confirms the practical feasibility of the proposed approach, which resulted in a 4-5 dB reduction in ACLR in the analyzed scenario.

eess.SP

Integrated Terahertz Photonic Receiving Frontend with Link Noise Outperforming Electronics

Terahertz technology is a key enabler for sixth-generation (6G) wireless networks, yet its application is constrained by increasingly severe free-space loss at high frequencies. To efficiently retrieve weak signals at the receiving end, a compact frontend that features both a high-gain antenna and a low-noise signal-detection chain is critical. Current transistor-based THz electronic frontends face significant challenges in meeting these demands because both on-chip antenna efficiency and transistor noise performance degrade rapidly when approaching their cut-off frequencies. Photonic technology provides an alternative solution to circumvent the transistor bandwidth limit, yet most microwave photonic links to date exhibit noise performance substantially worse than state-of-the-art electronics. Here, we demonstrate low-noise integrated THz photonic frontends that deliver undegraded link noise performance across three major THz windows from 140 to 450 GHz, and outperform electronic frontends in the upper two windows. We achieve this through co-design of high-gain on-chip THz antenna array and broadband THz-optic modulator on a single thin-film lithium niobate (TFLN) chip, leading to distributed reception of free-space THz signals and continuous coherent build-up of the THz-optic conversion process with unprecedented efficiency. Combined with an efficient heterodyne detection chain, our integrated frontends exhibit effective isotropic noise figures of 13.6 and 16.2 dB at 250 and 450 GHz, respectively, both setting new benchmarks in their respective bands. We further demonstrate 6G-oriented multi-link communication up to 20 Git/s. Our integrated frontends represent a significant step towards compact, cost-effective and energy-efficient THz wireless systems in 6G and beyond.

physics.optics

Plane Spiral OAM Mode-Group Based MIMO Communications: An Experimental Study

Spatial division multiplexing using conventional orbital angular momentum (OAM) has become a well-known physical layer transmission method over the past decade. The mode-group (MG) superposed by specific single mode plane spiral OAM (PSOAM) waves has been proved to be a flexible beamforming method to achieve the azimuthal pattern diversity, which inherits the spiral phase distribution of conventional OAM wave. Thus, it possesses both the beam directionality and vorticity. In this paper, it's the first time to show and verify novel PSOAM MG based multiple-in-multiple-out (MIMO) communication link (MG-MIMO) experimentally in a line-of-sight (LoS) scenario. A compact multi-mode PSOAM antenna is demonstrated experimentally to generate multiple independent controllable PSOAM waves, which can be used for constructing MGs. After several proof-of-principle tests, it has been verified that the beam directionality gain of MG can improve the receiving signal-to-noise (SNR) level in an actual system, meanwhile, the vorticity can provide another degree of freedom (DoF) to reduce the spatial correlation of MIMO system. Furthermore, a tentative long-distance transmission experiment operated at 10.2 GHz has been performed successfully at a distance of 50 m with a single-way spectrum efficiency of 3.7 bits/s/Hz/stream. The proposed MG-MIMO may have potential in the long-distance LoS back-haul scenario.

eess.SP

Theoretical analysis of the non-uniform OAM source based on an equivalent source transformation

Orbital angular momentum (OAM) has gradually become a research hotspot in radar, communication and other fields because of its phase distribution. However it encounters some problems in the real practice owing to its inherent characteristics. Recently OAM mode group has been proposed to solve these problems. In this paper, a non-uniform OAM source is used to generate the OAM mode-group (MG) directly. The radiation field is analyzed based on an equivalent source transformation. Taking the partial arc transmitting (PAT) scheme as an example, the non-uniform source is equivalenced as a group of uniform OAM sources by calculated its Fourier transform. This work provides theoretical guidance for the design of non-uniform OAM antenna in the RF domain.

physics.class-ph

A Compact Pattern Reconfigurable Antenna Based on Multimode Plane Spiral OAM

Orbital angular momentum (OAM) has attracted great interest in the past few decades due to its helical phase characteristics. It has been proved that Plane spiral OAM (PSOAM) has potential in pattern reconfiguration of azimuthal domain because it solves the difficulty of mode superposition caused by different main lobe directions of different modes. However, the absence of a compact high-purity multimode PSOAM antenna hinders the development of PSOAM applications. In this paper, a compact high-purity 8-mode PSOAM antenna consisting of a coaxial resonator group (CRG) and a rotating parabolic reflector (RPR) is designed. It works in the X-band with the bandwidth of 140 MHz, and its efficiency is greater than 90$\%$. Amplitude and phase of each PSOAM beam generated by this antenna can be controlled independently owing to its feed network and separate resonators design, hence any target pattern in azimuthal domain can be approximately reconfigured by modes weighting. The simulation and experiment results show that this antenna can make the PSOAM based pattern configuration possible, which will have potential in the OAM based applications.

physics.class-ph

OAM Mode-Group Generation Method: Partial Arc Transmitting Scheme

A partial slotted curved waveguide leaky-wave antenna which can generate orbital angular momentum (OAM) mode-groups (MG) with high equivalent OAM order negative and positive 40 at 60 GHz is proposed in this paper. The proposed antenna with partial slotting is designed according to the circular traveling-wave antenna which can generate single conventional OAM wave, so it can be regarded as partial arc transmitting (PAT) scheme compared with the full 2pi aperture slotting of the circular traveling-wave antenna. The full-wave simulation results show that the generated OAM MGs present a high gain beam with a helical phase distribution. This method may lead to novel applications for next generation communication and radar system.

eess.SP