查看更多>>摘要：In order to deeply study the characteristics and laws of downlink beam in satellite in-orbit motion, this paper proposes a multi-attitude disturbing force-GNNRL (DF-GNNRL) simulation technique based on satellite downlink beam calculation. The technique first studies the satellite in-orbit motion law and the calculation parameters of downlink beam under multi-attitude adjustment, establishes the mathematical model with corresponding arithmetic power on this basis, completes the data flow analysis of multiple models in the calculation process, further designs the coding algorithm, realizes the real-time data calculation and multi-terminal storage, builds the satellite multi-attitude DFGNNRL digital twin, and finally completes the satellite multi-attitude DF-GNNRL digital twin by means of information technology. The application of this technology can provide a strong analysis basis and data support for satellite in-orbit motion and downlink beam calculation under virtual simulation conditions.
查看更多>>摘要：This study illustrates a dual-band circular and pentagon antenna with dual-band configuration for the high return loss. When an antenna has a greater return loss, less power is reflected toward the transmitter, implying that the antenna and transmission line are better suited. Due to its accessibility, the FR4 substrate is used to replicate the design. With a bandwidth of 150 MHz and 200 MHz, respectively, the antenna's dual-band performance is between 2.32 GHz to 2.47 GHz and 2.9 GHz to 3.1 GHz. The body phantom design in CST Studio is used to test the design's biocompatibility. It is demonstrated by the improved antenna in the industrial, scientific, and medical (ISM) band region that it can be utilized for telemetry or medical services.
查看更多>>摘要：Present communication devices are adopting an application-centric approach with the integration of electronic gadgets into wearable accessories in recent years. This paper presents a wearable antenna with a flexible textile substrate. The design comprises a low-profile, textile-based UWB (3.1−10.6 GHz) antenna of 25 × 20 × 1 mm 3 size with a defected ground structure. Design antenna performance characteristics have been simulated in Computer Simulation Technology studio. It offers a gain of 4.204 dBi at 5.11 GHz frequency and 2.993 dBi at 7.39 GHz frequency using a cotton substrate with a 1.6 dielectric constant. A simulated testing of the design antenna on a human body phantom has resulted in a gain of 0.697 dBi with a return loss of −30.863dB and 1.058 VSWR at 5.3125 GHz frequency. A specific absorption rate value of 1.64 W/kg of the designed antenna for 10 g tissue shows that it is safe for the human body. The patch antenna of the paper is promising for wearable, medical imaging, tumor detection, and other wireless body area network (WBAN) biomedical applications.
查看更多>>摘要：In this article, a compact and planar antenna is designed and investigated. The design is inspired by the hexagonal shape. The proposed design has a bandwidth of 11.22 GHz, from 3.16 GHz to 14.38 GHz. A suitably placed inverted-U slot in the patch generates a WLAN band notch. The overall size of the design is 20 × 26 mm 2 (0.21 × 0.27 λ 0 2 in terms of its highest wavelength). It is suitable to achieve a radiation pattern that is almost omnidirectional and has a maximum gain of 4 dBi in the passband. Simulated data is verified with the measured data and found to be in good agreement. The proposed design is suitable for sub-6 GHz, band-notched ultra-wideband, V2X, and modern wireless high-data-rate communication applications. KEY WORDS: defected ground, hexagonal shape, planar design, ultra-wideband, WLAN band notch
查看更多>>摘要：In the movement area of an airport, the wireless communication system is built to satisfy the communication requirements of mobile stations (MSs), which include aircraft, vehicles, staff, passengers, and sensors. However, the actual airport wireless communication system is a heterogeneous wireless network with multiple individual wireless communication systems. In this paper, we design a multiprotocol base station (MPBS) to realize the access and interconnection of the MSs with different protocols. In addition, a direct forwarding scheme of MPBS is proposed to improve the performance of transmissions from one MS to another. Third, a priority order transmission scheme, which can reduce the end-to-end delay of important data, is proposed for direct forwarding MPBS. Simulation results show that the proposed direct forwarding MPBS scheme can improve the transmission performance of interactive data and reduce the load of the core network.
查看更多>>摘要：The popularity of multiple-in, multiple-out (MIMO) technology in wireless communication systems has increased due to its ability to enhance system capacity, coverage, and reliability, leading to a rising interest in designing and implementing MIMO antennas for various frequency bands, such as the S-band. However, mutual coupling between multiple antennas can pose a significant challenge in the performance analysis of MIMO systems. In this study, we introduce a novel approach involving the utilization of an L-shaped slot in a patch element placed on an economical FR4 epoxy material with a relative permittivity of 4.4 and a loss tangent of 0.02. Multiple antennas are strategically positioned in an orthogonal arrangement to minimize coupling effects. Our proposed antenna design successfully achieves an impedance bandwidth that aligns with the −10 dB reference over a frequency range from 2.78 GHz to 2.66 GHz, making it suitable for S-band satellite applications. Furthermore, by employing a four-element MIMO antenna setup, we achieve excellent isolation characteristics, with values below −20 dB. To ensure excellent MIMO performance, we consider some diversity parameters such as envelope correlation coefficient (ECC) and diversity gain (DG), which we investigate and find to be within standard limits (ECC < 0.04, DG = 10 dB). Our study offers valuable insights into designing and optimizing MIMO antennas for S-band satellite applications and can serve as a useful reference for future research in this area.
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