Membrane Antenna Research Articles

Design and demonstration of a roll-out membrane antenna based on thin-walled deployable composite booms

The thin-walled deployable composite boom (DCB) features the advantages of high deployment-to-package envelope ratio and elastic self-development, which is an enduring topic of interest in the field of lightweight aerospace structures. The structural design and performance demonstration was proposed herein for a roll-out membrane antenna (ROMA) based on DCBs. Firstly, a simplified analytical algorithm was formulated for approximate fundamental frequencies of the ROMA frame structure, and the two types of first-order torsional modal shapes of the frame structure was investigated with respect to configurational design parameters. In sequentially, the bending, swing and the two distinct torsional fundamental frequencies of the ROMA frame were estimated comparatively. Furthermore, the effects of the equilibrated tension from the membrane array on the bending fundamental frequency of the ROMA structure was investigated by assuming a simplified mass distribution model for the thin-film structures. Finally, The simplified analytical algorithm was used for structural design of an AIS/VDE (automatic identification system/VHF data exchange system) ROMA and its performance was validated through numerical simulations and ground tests. The successful deployment and operation of the AIS/VDE ROMA on the Pujiang-2 satellite further demonstrated the practical aerospace application significance of thin-walled DCBs.

Boom-Membrane Space Structure’s Incomplete Deployment After Storage in OrigamiSat-1 Ground Demonstrator

This study investigates the deployment reliability of multifunctional membrane deployable space structures that can be compactly stored and deployed in a two-dimensional direction using carbon composite booms to realize the construction of thin-film solar arrays and membrane antennas. Herein, two aspects are experimentally clarified using the structural models of a nano-satellite OrigamiSat-1, which is a 1 m-by-1 m square multifunctional deployable membrane structure demonstrator. First, a measurement system is developed to quasi-statically quantify the deployment torque of the structural models that failed to complete deployment after long-term storage and fell into an undesirable equilibrium shape. The measurement results confirm that the deployment torque decreases with long-term storage of the structure, and the torque in the deployment direction becomes negative at the deployment angle of the undesirable equilibrium shape. Therefore, as the second contribution, design modifications are made to the boom and membrane, and quasi-static and dynamic deployment tests are employed to evaluate their effects. The deployment reliability evaluation method and two design updates proposed herein will contribute to future space demonstrations and the utilization of lightweight membrane deployment structures with high packaging efficiency.

Inhomogeneous energy transfer dynamics from iron-stress-induced protein A to photosystem I.

Cyanobacteria respond to iron limitation by producing the pigment-protein complex IsiA, forming rings associated with photosystem I (PSI). Initially considered a chlorophyll-storage protein, IsiA is known to act as an auxiliary light-harvesting antenna of PSI, increasing its absorption cross-section and reducing the need for iron-rich PSI core complexes. Spectroscopic studies have demonstrated efficient energy transfer from IsiA to PSI. Here we investigate the room-temperature excitation dynamics in isolated PSI-IsiA, PSI, IsiA monomer complexes and IsiA aggregates using two-dimensional electronic spectroscopy. Cross analyses of the data from these three samples allow us to resolve components of energy transfer between IsiA and PSI with lifetimes of 2-3 ps and around 20 ps. Structure-based Förster theory calculations predict a single major timescale of IsiA-PSI equilibration, that depends on multiple energy transfer routes between different IsiA subunits in the ring. Despite the experimentally observed lifetime heterogeneity, which is attributed to structural heterogeneity of the supercomplexes, IsiA is found to be a unique, highly efficient, membrane antenna complex in cyanobacteria.

Large-scale array for radio astronomy on the farside (LARAF).

At the Royal Society meeting in 2023, we have mainly presented our lunar orbit array concept called DSL, and also briefly introduced a concept of a lunar surface array, LARAF. As the DSL concept had been presented before, in this article, we introduce the LARAF. We propose to build an array in the far side of the Moon, with a master station which handles the data collection and processing, and 20 stations with maximum baseline of 10 km. Each station consistsof 12 membrane antenna units, and the stations are connected to the master station by power line and optical fibre. The array will make interferometric observation in the 0.1-50 MHz band during the lunar night, powered by regenerated fuel cells. The whole array can be carried to the lunar surface with a heavy rocket mission, and deployed with a rover in eight months. Such an array would be an important step in the long-term development of lunar-based ultralong wavelength radio astronomy. It has a sufficiently high sensitivity to observe many radio sources in the sky, though still short of the dark age fluctuations. We discuss the possible options in the power supply, data communication, deployment etc. This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades (part 2)'.

High surface accuracy design of the electrostatically controlled deployable membrane antenna based on a thermoplastic forming method

High surface accuracy design of the electrostatically controlled deployable membrane antenna based on a thermoplastic forming method

The Choice of Mesh Size and Integration Points Number for the Electrostatically Controlled Membrane Antenna Structural-Electromagnetic Coupling Model

The Choice of Mesh Size and Integration Points Number for the Electrostatically Controlled Membrane Antenna Structural-Electromagnetic Coupling Model

The Establishment and Analysis of the Structural-Electromagnetic Coupling Model of the Electrostatically Controlled Deployable Membrane Antenna

The Establishment and Analysis of the Structural-Electromagnetic Coupling Model of the Electrostatically Controlled Deployable Membrane Antenna

Review of dynamics and active control of large-scale space membrane antenna

Review of dynamics and active control of large-scale space membrane antenna

The electrical design of a membrane antenna for a lunar-based low-frequency radio telescope

The electrical design of a membrane antenna for a lunar-based low-frequency radio telescope

Numerical and experimental study on the dynamic equivalent methodology of a membrane antenna structure and a grid membrane structure

The dynamic equivalent methodology utilizing a grid membrane substitute for a planar membrane for vibration test verification on the ground has been demonstrated in small sizes with simple constraints. The method lacks accuracy and validity for a real complex membrane antenna. This paper thus focuses on the applicability of the equivalence approach to a membrane antenna and the factors affecting its dynamic equivalence to verify whether the grid membrane structure can replace the membrane antenna structure for modal identification on the ground. To this end, an experimental system is developed to conduct vibration tests on the grid membrane structure in air, using the grid membrane model with unidirectional tension as a substitute for the membrane array. The connecting strips attach the grid membrane to thin-walled lenticular booms (TWLBs) to allow for unidirectional tension. A laser displacement sensor array is employed to obtain the vibration data. A combination of the Fast Fourier Transfer (FFT) and Stochastic Subspace Identification (SSI) methods is applied to identify the structural frequencies and mode shapes. Vibration tests on the grid membranes with different added masses and tensile forces are conducted. Meanwhile, the numerical results for the rectangular membrane are chosen as a reference for comparison with the experimental results for the grid membrane. In conclusion, the numerical results for the membrane antenna structure and the experimental results for the grid membrane structure show good agreement in terms of frequency and mode shape. Additionally, both the added masses in the intersection areas of the grid membrane and the tensile force have a significant effect on the dynamic equivalence.

Hybrid vibration control of the membrane antenna experiencing maneuver with cable actuators

This work investigates a novel hybrid vibration control approach of a membrane antenna with cable actuators considering the rigid-flexible coupling effect induced by maneuver. The dynamic model of the membrane antenna is first formulated using finite element analysis, incorporating nonlinearity and rigid-flexible coupling. Tension cables are selected as actuators due to their wide influence range and lightweight properties, without the need for additional accessories on the membrane. Based on these foundations, a hybrid control strategy is proposed, comprising two sub-controllers for the during-maneuver and after-maneuver stages. The feedforward sub-controller during maneuver is designed based on the system's transfer function and optimized using the genetic algorithm, with the purpose of minimizing shape deflection. The feedback sub-controller for post-maneuver vibration suppression is designed based on the linear quadratic regulator (LQR), with a general controller expression of cable actuators provided. Finally, numerical simulations demonstrate the robustness and efficiency of the proposed control scheme for the membrane antenna. The proposed scheme leverages the rapid responses of feedforward control and reliable suppression of feedback control, offering a new perspective on control scheme design for maneuver-induced vibration and presenting a general controller expression for cable actuators based on state space equations.

Cable-based pattern recognition for close-loop vibration control of membrane antenna

Though various control schemes have been investigated numerically for vibration control of large-scale membrane structure, there has not presented any practical method to recognize dynamic pattern from sensing signals. This study proposed a novel cable-based dynamic pattern recognition method of large-scale membrane antenna, giving the first-time practical implementation of full-state reconstruction for feedback control. Cubic polynomial function is adopted to reconstruct the pattern based on the displacements and angles of corresponding cables, according to the way vibration goes. To further improve the accuracy and continuity, convolutional correction and Kalman filter are applied. The pattern recognitions are compared in both physical and modal way via free vibration. And the performance of reconstructed shape in close-loop control is verified based on linear quadratic regular (LQR) controller. Simulations show that the proposed pattern recognition method can reasonably reconstruct the out-of-plane shape, and the suppression of vibration is as good as that in full-state-available case. With correction algorithms applied, the control force signals become realizable and practical, whose continuity is notably improved. This method introduces a novel technique to achieve full-state feedback for the first time, making it possible to realize many excellent control methods in practice.

Nonlinear model order reduction and vibration control of a membrane antenna structure

In this paper, model order reduction (MOR) of the nonlinear dynamic model of a membrane antenna structure is studied. Nonlinear vibration control of the membrane antenna structure by using cable actuators has also been investigated. First, the nonlinear dynamic model of the membrane antenna structure is established by using the nonlinear finite element method. Then, MOR of this nonlinear model is carried out. The vibration modes obtained by the linearized model are used as transformation bases, and the method of polynomial fitting is applied to approximate the nonlinear terms. Based on the reduced nonlinear dynamic model, by using the tension cables as actuators, a vibration controller is proposed to suppress the nonlinear vibration of the structure. The nonlinear vibration of the membrane antenna structure is suppressed by adjusting the tension force in the cable actuators. Numerical simulations show that the reduced dynamic model obtained by the presented MOR method can approximate the original nonlinear model very well meanwhile reduce the calculation cost significantly, and the nonlinear vibration of the structure can be suppressed effectively by the cable actuators with the proposed control law.

Nonlinear Dynamics of a Space Tensioned Membrane Antenna during Orbital Maneuvering

Due to the super flexibility and strong nonlinearity of space membrane antennas, the dynamic response of a space membrane antenna will be affected by the rigid–flexible coupling effect in the process of orbital maneuvering. In this case, the dynamic model of a tensioned membrane antenna is significantly different from that under the general condition (fixed boundary). In this study, a nonlinear dynamic model of a tensioned space membrane antenna experiencing maneuvering is established, and the influence of the rigid–flexible coupling effect on structural stiffness and damping characteristics is described. Through a numerical solution, the effects of rigid body motion and structural natural frequency on the rigid–flexible coupling effect are discussed. The results show that the vibration frequency and amplitude of the antenna are positively correlated with the acceleration and initial velocity of rigid body motion. With the increase of the natural frequency of the antenna, the vibration frequency increases but the amplitude decreases. The rigid–flexible coupling nonlinear dynamic model proposed in this work is more applicable in intelligent vibration control compared to finite element software.

Model updating and vibration control of membrane Antenna spacecraft based on on-orbit modal identification

In this paper, on-orbit modal identification of membrane antenna spacecraft is investigated. Based on the modal identification results, dynamic model of the spacecraft is updated, and a vibration controller is designed. First of all, the rigid-flexible coupling dynamic model of the membrane antenna spacecraft is established by using Lagrange equation. Then, the covariance driven stochastic subspace identification (SSI-COV) method, which only relies on output measurements of the system under ambient excitation, is adopted to identify the modal parameters. By using the modal identification results, the model updating is performed based on sensitivity analysis, and vibration controller is designed to suppress the vibration caused by attitude maneuver based on the component synthesis vibration suppression (CSVS) method. Simulation results show that the SSI-COV method can identify the modal parameters of the membrane antenna spacecraft effectively, the updated dynamic model produces obvious improvements over the original model, and the vibration suppression effect of the CSVS controller is improved significantly after model updating.

Analysis of the designs of membrane transformable antennas for spacecraft

This paper presents an analysis of various designs of transformable membrane reflector antennas for spacecrafts, considers the dependence of the surface accuracy on the operating frequency of the antenna and the requirements imposed on deviations of the antenna surface from the paraboloid. A classification of membrane transformable antennas is presented depending on the presence or absence of supporting elements and stiffeners. Structural schemes for opening membrane antennas are described, from the classical umbrella opening scheme to original schemes for winding ribs on a central hub, tension supporting elements, winding paraboloid segments on a central hub, and folding the reflector surface using origami methods. The design of an offset membrane transformable antenna is considered. Modern materials for the manufacture of reflectors of membrane antennas, such as polymer composite materials with triaxial weaving of carbon fabric with a silicone matrix, polyamide and polyimide films with and without reinforcement, are considered. Materials with shape memory for opening membrane antennas are considered. Calculations of structures for natural vibration frequencies, calculations for bending of folds are described. A description of ground-based experimental testing, in particular, for the disclosure of various types of membrane antennas, was carried out.

Ultrabroadband terahertz time-domain spectroscopy using III-V photoconductive membranes on silicon

Electromagnetic waves in the terahertz (THz) frequency range are widely used in spectroscopy, imaging and sensing. However, commercial, table-top systems covering the entire frequency range from 100 GHz to 10 THz are not available today. Fiber-coupled spectrometers, which employ photoconductive antennas as emitters and receivers, show a bandwidth limited to 6.5 THz and some suffer from spectral artifacts above 4 THz. For these systems, we identify THz absorption in the polar substrate of the photoconductive antenna as the main reason for these limitations. To overcome them, we developed photoconductive membrane (PCM) antennas, which consist of a 1.2 µm-thin InGaAs layer bonded on a Si substrate. These antennas combine efficient THz generation and detection in InGaAs with absorption-free THz transmission through a Si substrate. With these devices, we demonstrate a fiber-coupled THz spectrometer with a total bandwidth of 10 THz and an artifact-free spectrum up to 6 THz. The PCM antennas present a promising path toward fiber-coupled, ultrabroadband THz spectrometers.

Thermal Analysis and Rigid-Flexible Coupling Dynamics of a Satellite with Membrane Antenna

In this paper, the thermal analysis of a membrane antenna structure is performed, and then, the rigid-flexible coupling dynamic modeling and control of the membrane-antenna-satellite system are studied with the thermal stress considered. The thermal analysis model of the membrane antenna structure is derived based on the finite element method by discretizing the structure into 1D and 2D thermal elements. Considering the thermal stress, the vibration modes of the membrane antenna structure are obtained, and the rigid-flexible coupling dynamic model of the membrane-antenna-satellite system is derived based on the hybrid coordinate method. To reduce the vibration of the membrane antenna structure caused by the attitude maneuver, the control command is designed based on the component synthesis vibration suppression (CSVS) method. Simulation results show that the dynamic properties of the membrane antenna structure are affected significantly by the space thermal environment, the vibration of the membrane antenna structure can be suppressed effectively by the presented CSVS controller, and the accuracy of the attitude maneuver will be improved significantly by the proposed control strategy.

Development simulation of an inflatable membrane antenna based on extended position-based dynamics

Development simulation of an inflatable membrane antenna based on extended position-based dynamics

A Review on the Development of Spaceborne Membrane Antennas

The membrane antenna technology is a very promising approach to obtain large aperture with light weight and low stowed volume. In the past decades, extensive studies have been carried out on active and passive membrane antennas. However, the practical spaceborne applications are rare due to many challenges, e.g., the surface accuracy maintenance, the on-orbit reliability, and the environmental compatibility. This paper summarizes the history and state-of-art progresses on spaceborne membrane antennas. Curved surface reflectors, conformal active membrane antennas, planar array membrane antennas, and planar reflectarray membrane antennas have been introduced, respectively. Radiofrequency design, deploying mechanism, material, experiment, application, and analysis method have been presented. By concluding the advantages and challenges of the current membrane antennas, this paper is aimed at providing a perspective of the existing problems and future trend of spaceborne membrane antennas.