Satellite Communication Applications Research Articles

Conversion of 10 min Rain Rate Time Series into 1 min Time Series: Theory, Experimental Results, and Application in Satellite Communications

We propose a semi-empirical method—based on a filtered Markov process—to convert 10 min rain rate time series into 1 min time series, i.e., quasi-instantaneous rainfall—the latter to be used as input to the synthetic storm technique, which is a very reliable tool for calculating rain attenuation time series in satellite communication systems or for estimating runoff, erosion, pollutant transport, and other applications in hydrology. To develop the method, we used a very large data bank of 1 min rain rate time series collected in several sites with different climatic conditions. The experimental and simulated 1 min rain rate time series agree very well. Afterward, we used them to simulate rain attenuation time series at 20.7 GHz, in 35.5° slant paths to geostationary satellites. The two simulated annual rain attenuation probability distributions show very small differences. We conclude that the rain rate conversion method is very reliable.

Analysis and Design of a Six-Port Network Based on a Modified Schiffman Phase Shifter

Purpose: This study presents a novel design of a six-port network based on a modified Schiffman phase shifter operating at a 90±2° phase shift. Design/ Methodology/ Approach: The research methodology encompasses a comprehensive literature review, the analysis, design and simulation of the novel phase shifter, its integration into a six-port network, layout design and subsequent post-layout simulation, and comparative analysis to evaluate the new design's performance. Findings: The schematic results showed an operational bandwidth from 5.52 GHz to 12.21 GHz, translating to a fractional bandwidth of 75.47% with a maximum phase error of ±1.8° for the 90° phase shift. Also, the post-layout simulation results from momentum demonstrated outstanding performance with an operation frequency band spanning from 5.52 GHz to 12.21 GHz, representing a factional bandwidth of 75.47% and ±2.1° phase error across the entire band. In addition, good impedance matching was achieved at all the ports well below -10 dB. Practical Implications: It also finds application in satellite communications, where beamforming enhances signal strength and quality by directing the signal towards specific locations on Earth, and antenna arrays for satellite uplink and downlink antennas adjust the beam direction and coverage area dynamically. Social Implications: The social impact of this work includes high-performing communication devices for current and future generations, more accurate measurements, particularly wearable devices in healthcare for monitoring human vitals, weather monitoring systems, high-precision radar systems, wireless gadgets, high-data-rate communication systems, and Internet of Things (IoT) devices. Originality and Value: The study contributes to the existing body of knowledge by introducing an innovative design that addresses the limitations of phase accuracy and bandwidth in Six-Port Networks.

Dual circularly polarized dual-band antenna combining transmitarray and reflectarray for K/Ka-band uplink and downlink satellite communication

This paper presents a dual-band antenna system utilizing transmitarray (TA) and reflectarray (RA) having dual-circularly polarized (CP) characteristics for K/Ka-band satellite communication. The antenna consists of the TA and RA surfaces operating at 19.5 GHz and 29.7 GHz respectively. The RA is designed on a single substrate layer with element size of 0.30 λ × 0.30 λ (λ corresponding to 30 GHz), whereas the TA is designed on two substrate layers with element size of 0.33 λ × 0.33 λ (λ corresponding to 20 GHz). The equivalent circuit model (ECM) of the TA and RA elements is extracted to validate the working of the proposed elements. A small window of the size of a patch antenna is cut in both the RA and TA surfaces to accommodate the coaxially-fed illuminating sources. The antenna shows the peak gain of 17 dBiC at 19.5 and 29.7 GHz. The 3 dB axial ratio bandwidths range from 19.3–19.6 GHz (1.55 % ) and 29.5–29.9 GHz (1.35 % ) in the two frequency bands. The antenna radiates two orthogonally polarized CP waves at two frequency bands which makes the antenna suitable for satellite communication applications.

1‐Bit reconfigurable reflectarray antenna with T‐shaped parasitic structure

AbstractIn this paper, an electronically 1‐bit reconfigurable reflectarray antenna (RRA) with wide‐angle beam‐scanning and high efficiency performance is presented for formation satellite communication applications. A 1‐bit phase distribution can be generated by controlling the state of the PIN dipole in the configurable element comprising a double split ring (DSR) patch and two T‐shaped parasitic structures. The resonant frequency of the DSR patch in both states can be optimised by a T‐shaped parasitic structure, which is beneficial to improving the bandwidth and aperture efficiency. A 180° ± 20° phase difference can be realised from 9.7 to 10.3 GHz only by controlling one PIN dipole loaded on the proposed element, which ensures stable radiation performance over a larger band. To validate the effectiveness of the proposed element, a prototype RRA containing 20 × 20 units is designed and measured. A ±60° beam scanning range with the gain drop of 3.2 and 3.3 dB in the xoz and yoz planes is realised, which verifies the wide‐angle beam‐scanning ability of the RRA. The measured peak gain is 25 dBi at 10 GHz in the broadside direction, corresponding to an aperture efficiency of 25.2%. Meanwhile, the 1‐dB gain bandwidth of the proposed RRA is 12.6%.

Sandwich-Structured Fluorinated Polyimide Aerogel/Paraffin Phase-Change Composites Simultaneously Enables Gradient Thermal Protection and Electromagnetic Wave Transmission.

There is an emerging requirement of advanced functional materials for simultaneous thermal protection and electromagnetic wave-transparent transmission applications. A novel polyimide (PI) aerogel-based sandwich-structural composite is developed to meet such a requirement in this study. This composite is based on a unidirectional fluorinated PI (FPI) aerogel as a lower layer, a nondirectional conventional PI aerogel as a middle layer, and a nondirectional FPI aerogel/paraffin phase-change composite as an upper layer. The lower layer exhibits a unique unidirectional porous microstructure and an ultralow dielectric constant of 1.04. The upper layer possesses a dynamical temperature regulation capability thanks to its loaded paraffin having a high latent heat capacity of 242.7Jg-1. The presence of the nondirectional PI aerogel middle layer can effectively prevent against the leakage of paraffin from the upper layer to the surface of the composite. Through a rational integration of three functional layers, the developed sandwich-structured composite not only can provide gradient thermal protection for hot objects over a long period but also exhibits an excellent wave-transparent capability to establish communication between two electromagnetically shielded electronic devices. With such prominent thermal insulation and wave-transparent functions, the sandwich-structured composite exhibits great potential for specific applications in aircraft, spacecraft, radar systems, and satellite communication.

Performance Evaluation of Neuromorphic Hardware for Onboard Satellite Communication Applications

Performance Evaluation of Neuromorphic Hardware for Onboard Satellite Communication Applications

Design of a Half-Mode Substrate-Integrated Waveguide (HMSIW) Multimode Resonator Bandpass Filter Using the Minkowski Fractal for C-Band Applications.

A substrate-integrated waveguide (SIW) bandpass filter (BPF) with extraordinary selectivity and an adequate upper stopband for C-band Satellite Communication (SATCOM) applications is proposed in this paper. The design comprises comb-shaped slots engraved on a half-mode SIW (HMSIW) that constitute a multimode resonator (MMR). Its performance is further ameliorated by applying the first and second iterations of the Minkowski fractal curve in the ground plane as a defected ground structure (DGS). The Minkowski fractal has advantages in terms of better bandwidth and miniaturization. The filter is first simulated using the commercial full-wave electromagnetic simulator HFSS v19 and then fabricated on a 0.062'' (1.6 mm) FR4 with dielectric constant εr = 4.4. The measured results are comparable with the simulated ones and demonstrate that the BPF has a resonant frequency (f0) of 4.75 GHz, a 3 dB bandwidth of 770 MHz (fractional bandwidth of 21.4%), an insertion loss of 1.05 dB, and an out-of-band rejection (in the stopband) of more than 28 dB up to 8 GHz, demonstrating a wide and deep stopband. Using the multimode resonator (MMR) technique, a wide bandwidth has been achieved, and by virtue of using half-mode SIW (HMSIW), the proposed BPF is compact in size. Also, the fractal DGS aids in better stopband performance.

Optimized Graph Sample and Aggregate‐Attention Network‐Based High Gain Meta Surface Antenna Design for IoT Application

ABSTRACTThis paper presents a High Gain Metasurface (HGM) antenna design optimized for IoT applications. The antenna operates at a 5.8 GHz frequency and utilizes a quarter‐wavelength unit cell structure. The design employs a Graph Sample and Aggregate‐Attention Network (GSAAN) to enhance the transmission characteristics of the metasurface. To optimize the performance of GSAAN, the Giza Pyramids Construction Algorithm (GPCN) is applied to adjust the weight parameters, leading to significant improvements in radiation efficiency, bandwidth, gain, directivity, and return loss. The proposed HGM antenna is simulated in MATLAB 2023b, where it demonstrates substantial performance gains over existing methods. Specifically, the proposed design achieves 28.34% higher gain compared to the MSA‐RHCOA method, 24.47% improvement over HGM‐AD‐MATCS, 26.34% better gain than BR‐HGA‐PGM, and a 32.12% gain increase relative to MSA‐Hyb‐ADSA‐HMSOA. These enhancements make the proposed antenna design a competitive solution for high‐gain applications in wireless communication, satellite communication, and radar systems. The integration of GSAAN with GPCN optimization in the HGM antenna design enables the creation of highly directive radiation patterns, making it well‐suited for IoT applications that require high performance and reliability. The results of this study demonstrate the effectiveness of the proposed approach in achieving superior antenna performance, positioning it as a strong alternative to existing metasurface antenna designs.

Achieving high efficiency and bandwidth enhancement of DRA arrays: Synergic effects of LiMg4AlO6 microwave dielectric ceramic and 2D metamaterials

In this paper, LiMg4AlO6 ceramics with a sintering temperature of 1380 °C to 1460 °C are prepared, and the microwave dielectric properties of the ceramics and their potential application in dielectric resonator antenna (DRA) arrays are investigated. Analysis techniques such as XRD and Rietveld refinement reveal that the LiMg4AlO6 ceramics are rock salt structures and the space group is Fm-3 m (225). The ceramic obtained excellent microwave dielectric properties (εr = 10.17, Q×f = 172, 558 GHz, and τf = - 32.5 ppm/ °C) at 1440 °C. The εr of LiMg4AlO6 ceramics exhibits minimal variation across a wide temperature range (-100 °C to 400 °C) without phase transition. Furthermore, the 2D metamaterials (metasurfaces) are introduced in the DRA, which can significantly improve the radiation efficiency and bandwidth of the antenna. Measured results demonstrate that the antenna has a wide bandwidth ranging from 8.07 GHz to 8.57 GHz, with a maximum realized gain of 8.9 dBi and a peak radiation efficiency of 97%. The proposed ceramic antenna array combines the superior properties of 2D metamaterials and ceramic materials, which opens up a new avenue for ceramic antenna design and satellite communication applications.

Design and Simulation of Circular Dielectric Resonator Antenna and Investigation of Structure, Microstructure, and Dielectric Properties of Mn‐Modified Sr2SnO4

Samples with compositions of Sr2Sn1−xMnxO4(SSM) with 0 ≤ x ≤ 0.10 are prepared by conventional ceramic route via heat treatment at 1350 °C. Phase and crystal structure analysis is studied using X‐ray diffraction and Rietveld refinement to confirm the crystallization of samples in the tetragonal structure under space group I4/mmm. The size‐strain plot method is employed to identify the role of Mn on crystallite size/microstrain/dislocation density. The scanning electron microscope and energy‐dispersive X‐ray spectroscopy analysis confirm a significant change in the grain size and compositional homogeneity of all samples with Mn‐doping. Dielectric properties of samples are explained in terms of interfacial and orientation polarization of dipoles . Modulus studies show the exclusion of electrode contribution from the electrical properties. The single‐segment circular dielectric resonator antenna is designed with the help of experimental dielectric parameters and showed two major resonant frequencies at 3.6 and 6.7 GHz. The reduction in the S11 parameter and −10 dB reflection coefficient bandwidth with Mn‐doping observed due to overlapping of the E‐field line suggests the application in patch array antenna for radar and satellite communication applications. This study also enables to explore Sr2SnO4‐based Ruddlesden Popper oxide for antenna and mm‐wave communication applications.

A compound reconfigurable series-fed microstrip antenna for satellite communication applications

PurposeThis paper aims to present an innovative reconfigurable series-fed microstrip antenna using radiofrequency positive intrinsic negative (RF PIN) diodes for cognitive S-band and C-band satellite communications. The antenna can dynamically reconfigure its frequency, polarization and radiation pattern to meet diverse application needs.Design/methodology/approachThe design involves a reconfigurable four-element microstrip antenna using FR4 substrate and copper patches. RF PIN diodes enable dynamic frequency, polarization and radiation pattern reconfiguration. Simulations and optimizations are performed using CST and HFSS, using techniques like the Nelder-Mead algorithm, particle swarm optimization, covariance matrix adaptation and trust region framework. An antenna prototype is also fabricated to validate the simulations.FindingsThe proposed antenna demonstrates significant reconfigurability: it switches between S-band (2.45 GHz, 2.52 GHz) and C-band (5.55 GHz, 5.59 GHz) with bandwidths of 120 MHz and 550 MHz, respectively. It transitions between circular and linear polarization in the S-band and modifies the radiation pattern by 45 degrees, providing an alternative radiation direction in the C-band. The antenna achieves a maximum gain of 5.95 dBi at 2.52 GHz and 93% efficiency at 5.55 GHz. Simulated results closely match those from the fabricated prototype, confirming the design’s validity.Originality/valueThe innovative use of RF PIN diodes enables comprehensive reconfigurability in frequency, polarization and radiation patterns within a single microstrip antenna, meeting the demands of S-band and C-band satellite communications. This study demonstrates superior performance, significant gains and efficiencies across various reconfiguration modes, validated by rigorous simulation and practical fabrication. The simple structural design further distinguishes this study from others in the field.

Dual-frequency optical-microwave atomic clocks based on cesium atoms

133Cs, the only stable cesium (Cs) isotope, is one of the most investigated elements in atomic spectroscopy and was used to realize the atomic clock in 1955. Among all atomic clocks, the cesium atomic clock has a special place, since the current unit of time is based on a microwave transition in the Cs atom. In addition, the long lifetime of the 6P3/2 state and simple preparation technique of Cs vapor cells have great relevance to quantum and atom optics experiments, which suggests the use of the 6S−6P D2 transition as an optical frequency standard. In this work, using one laser as the local oscillator and Cs atoms as the quantum reference, we realize two atomic clocks at the optical and microwave frequencies. Both clocks can be freely switched or simultaneously output. The optical clock, based on the vapor cell, continuously operated with a frequency stability of 3.9×10−13 at 1 s, decreasing to 2.2×10−13 at 32 s, which was frequency-stabilized by modulation transfer spectroscopy and estimated by an optical comb. Then, applying this stabilized laser to an optically pumped Cs beam atomic clock to reduce the laser frequency noise, we obtained a microwave clock with a frequency stability of 1.8×10−12/τ, reaching 6×10−15 at 105 s. This study demonstrates an attractive feature for the commercialization and deployment of optical and microwave clocks, and will guide the further development of integrated atomic clocks with better stability. Therefore, this study holds significant practical implications for future applications in satellite navigation, communication, and timing.

Continuous manipulation of electromagnetic radiation based on ultrathin flexible frequency coding metasurface

The physical characteristics of electromagnetic waves are combined with digital information in coding metasurfaces. Coding metasurfaces enable precise control of beams by flexibly designing coding sequences. However, achieving continuous multivariate modulation of electromagnetic waves on passive flexible coded metasurfaces remains a challenge. Previous passive coding metasurfaces have a fixed phase difference between adjacent coding units throughout the operating frequency band, and when the coding pattern is defined, the coded metasurface can only achieve a single electromagnetic function. Our proposed frequency coding metasurface units vary linearly in phase difference over the operating frequency band with different phase sensitivities. Frequency coding metarsurfaces enable a wide range of tunable and versatile electromagnetic energy radiation, without introducing any active devices and changing the coding pattern. As a demonstration of the concept, we have shown theoretically and numerically that frequency coding metasurface can achieve successive transformations of electromagnetic functions, including multi-beam generation, anomalous deflection and diffuse scattering. In addition, beam sweeping function is achieved by means of spatially non-periodically distributed frequency coding metasurface. When the frequency of the incident wave is changed, the deflection angle of the beam is also changed. In addition to the tunability of properties, research on coding metasurfaces has tended to be limited to rigid materials. Flexible coding metasurfaces have potential applications in microwave antennas, radar and aircraft. The passive flexible frequency coding metasurfaces provide a novel approach to manipulating electromagnetic waves with increased design flexibility. This promises applications in microwave antennas, radar, aircraft, and satellite communications.

A compact wideband low‐profile all textile on/off body antenna for Satcom and defense applications

SummaryA compact, flexible, low‐profile end‐fire broadband wearable antenna operating in Ku‐band /X‐band is proposed in this manuscript for defense and satellite communications (Satcom) applications. The main objective of this work is cross‐polarization reduction by the defected ground structure (DGS), which offers a wider bandwidth. Due to its flexibility and ability to absolutely conform to the curved‐shaped human body, denim fabric is used as a substrate, whereas copper tape is used as a conductor, which allows for the integration of the antenna into garments and makes it appropriate for a wide range of wearable applications in various bands. The prototype has been developed with a size of mm3 for experimental validation. The measured results from a fabricated prototype are well matched with the simulated ones of the proposed design, which indicate a wide bandwidth of 57.35% (7.76–14 GHz) appropriate for use in applications such as defense operating from 8 to 12 GHz, satellite TV (11.7–12.2 GHz), Ku‐band downlink (10.95–11.7 GHz), Ku‐band uplink (11.7–14.5 GHz), and a high gain of 5.1 dBi. The specific absorption rate (SAR) is much below the permissible limit of 1.6 W/kg, with better radiation characteristics. Thus, the proposed antenna is more compact, and it clearly achieves a smaller footprint, larger impedance bandwidths, and a low SAR with potential prospect for Satcom and defense purposes.

3D-printed x-band 1-port TM01 circular waveguide to 4-port TE10 rectangular waveguide mode converter & power splitter

ABSTRACT This paper investigates a novel waveguide component design with dual functionality of mode conversion and power splitting. Because of its complex internal geometry which conventional fabrication methods cannot realize, additive manufacturing was explored, specifically selective laser melting. The end-to-end process of design, simulation, fabrication, and measurement will be discussed in detail. The said waveguide component converts between 4 rectangular waveguide TE10 mode and 1 circular waveguide TM01 mode. The 1 to 4 splitter was done while achieving low power splitting losses and mode conversion losses with low return losses. This allows for waveguide connections to be made between circular waveguides and rectangular waveguides at X-Band, which can be used for radars or satellite communication applications. The novelty of this component design comes from impedance matching between 4 rectangular waveguides operating in the fundamental mode and 1 single highly over-moded circular waveguide by means of coaxial rod and matching fins. All these are done while keeping the overall size small, compact, and lightweight.

Design of a Ku-band broadband circularly polarized magneto-electric dipole antenna for satellite communications

ABSTRACT In this paper, a broadband circularly polarized (CP) antenna array with stable radiation pattern is proposed for satellite communication applications. The antenna array consists of a 2 × 2 planar antenna array and a feeding network. Based on the magneto-electric (ME) dipole antenna structure, the electric dipoles are modified, and a pair of shorting pins are introduced to adjust the surface current. The bandwidth problems of circular polarization are effectively improved. Then the 2 × 2 broadband CP antenna array is designed and fabricated. The measured results show that the −10 dB impedance bandwidth of 56.3% from 11.1 to 19.79 GHz, and the 3 dB axial ratio (AR) bandwidth of 32.1% from 11.72 to 16.20 GHz. The 3 dB gain bandwidth of 44.2% from 11.10 to 17.40 GHz, and the peak gain is 11.07 dBi. Owing to the above excellent performance, the proposed antenna array can be a candidate for satellite communications.

Novel-shaped expandable quad-port MIMO antenna using FR4 material with features of high isolation and band width for 5G networks, Wi-Fi, and satellite communication applications

Novel-shaped expandable quad-port MIMO antenna using FR4 material with features of high isolation and band width for 5G networks, Wi-Fi, and satellite communication applications

Design of single layer bowtie wide band-stop frequency selective surface with angular stability for C-band applications

This paper presents the design and analysis of a single-layer wide band-stop frequency selective surface (FSS) tailored for C-band applications. The proposed FSS design employs a modified bow-tie unit cell structure that enhances band stop characteristics, resulting in improved performance compared to traditional FSS geometry. The design process involves numerical simulations and optimization techniques to achieve the desired frequency response. A modified bowtie element with FR4 substrate comprises the proposed FSS which exhibits a resonant frequency of 6.0 GHz with a wide bandwidth of 4.84–6.96 GHz (35.93 %) and act as a band stop filter. The FSS is analyzed in terms of its transmission coefficients, providing insight into its filtering properties. In addition, parametric studies of the unit cells are done. Furthermore, the angular stability of the proposed FSS is simulated with incident waves at various angles between 0° to 60° for both TE and TM modes. The proposed FSS presents C-band applications of WLAN, ISM/WiMAX, satellite communications, radar systems, shielding and communication devices, also enhancing filtering capabilities and system performance. The simulation results are well correlated with measurement results.

Design of Broadband High-Frequency Multi-Throw RF-MEMS Switches.

This paper introduces a broadband triple-pole triple-throw (3P3T) RF MEMS switch with a frequency range from DC to 380 GHz. The switch achieves precise signal control and efficient modulation through its six-port design. It achieves an insertion loss of -0.66 dB across its frequency range, with isolation and return loss metrics of -32 dB and -15 dB, respectively. With its low actuation voltage of 6.8 V and rapid response time of 2.28 μs, the switch exemplifies power-efficient and prompt switching performance. The compact design is ideal for integration into space-conscious systems. This switch is pivotal for 6G research and has potential applications in satellite communications, military radar systems, and next-generation radio applications that require multi-antenna access.

Dual-Polarization Conversion and Coding Metasurface for Wideband Radar Cross-Section Reduction

Modern stealth application systems require integrated meta-devices to operate effectively and have gained significant attention recently. This research paper proposes a 1-bit coding metasurface (CM) design. The fundamental component of the proposed CM is integrated to convert linearly polarized incoming electromagnetic waves into their orthogonal counterpart within frequency bands of 12.37–13.03 GHz and 18.96–32.37 GHz, achieving a polarization conversion ratio exceeding 99%. Furthermore, it enables linear-to-circular polarization conversion from 11.80 to 12.29, 13.17 to 18.44, and 33.33 to 40.35 GHz. A second element is produced by rotating a fundamental component by 90°, introducing a phase difference of π (pi) between them. Both elements are arranged in an array using a random aperiodic coding sequence to create a 1-bit CM for reducing the radar cross-section (RCS). The planar structure achieved over 10 dB RCS reduction for polarized waves in the frequency bands of 13.1–13.8 GHz and 20.4–30.9 GHz. A prototype was fabricated and tested, with the experimental results showing a good agreement with the simulated outcomes. The proposed design holds potential applications in radar systems, reflector antennas, stealth technologies, and satellite communication.