Figure - available from: Engineering Research Express
This content is subject to copyright. Terms and conditions apply.
Synthesis of multibeam antennas with flattened beams: (a) Geometry of anisotropic unit cell with dimensions 0.12λ 0 × 0.12λ 0; (b) Impedance distribution of the Zρρ - surface tensor component of seven-beam MSA.
Source publication
In this paper, we propose a novel method for synthesizing a multibeam metasurface antenna (MSA) for use in a space application - a payload component of a small satellite as part of a low Earth orbit (LEO) satellite communication constellation. MSA is synthesized using the holographic technique with a divergent phase distribution. Using this method,...
Citations
... In the literature, various multibeam antennas utilizing holography theory have been proposed. For example, multibeam HAs with fixed radiation patterns have been proposed [10], [11], [12], [13]. Attempts have also been made to vary the radiation patterns. ...
The requirements of low Earth orbit (LEO) satellite systems for high-precision and selective multiple coverage, have driven much interest and demand for millimeter-wave multibeam antennas. However, the key challenge is to provide fully independent control of each beam with a single source, and metasurfaces have paved the way to solve this problem. Here, we present a reconfigurable multibeam holographic antenna (HA) at 36 GHz. In particular, we used liquid crystals (LC) to implement a low power consumption and lightweight antenna. Each unit cell is selectively driven by connected bias lines according to the calculated holographic pattern. Consequently, the proposed multibeam HA can radiate in the desired direction and control each beam independently. Furthermore, the gain difference in each beam can be corrected by the amplitude coefficient to radiate with nearly equal gain in each direction. The proposed HA demonstrated the scanning range of 60° at 36 GHz, with a peak gain of 8.7 dBi. Additionally, the peak directivity is 12.7 dBi, the 3-dB bandwidth is about 1 GHz at the center frequency of 36 GHz, and the operating bandwidth is 2.8 GHz (34.8−37.6 GHz).
... In a transmit array, incident waves are transmitted to the other side and produce a forward beam, whereas, in a reflecting array, the energy is reflected and produces a backward beam. Considerable efforts have been made to extend their functionalities such as multiband operation [17], reconfigurability [18,19], and multibeam applications [20,21]. ...
This paper presents the design and optimization of a dual-band polarization-dependent metasurface capable of dynamically switching transmission and reflection characteristics. The metasurface is composed of three metallic patterns, with the bottom layer governing the reflection and transmission phase for both TE-polarization and TM-polarization states. The middle and top layers are strategically employed to ensure optimal transmission and reflection performance. The results confirm that the metasurface enables the transformation of the transmission band into a complete reflection band, and vice versa, through variations in the incident wave polarization. Remarkable transmission and reflection characteristics are achieved within the frequency ranges of 6.1–6.55 GHz and 8.9–9.3 GHz, respectively. The proposed metasurface offers promising applications in advanced communication systems and radar technology, enabling dynamic manipulation of electromagnetic waves.
... In a transmit array, incident waves are transmitted to the other side and produce a forward beam, whereas, in a reflecting array, the energy is reflected and produces a backward beam. Considerable efforts have been made to extend their functionalities such as multiband operation [17], reconfigurability [18,19], and multibeam applications [20,21]. ...
... Dual polarization and/or dual band reflect-arrays have been realized to manage both transmission and reception bands while maximizing the coverage area [20]. In addition, solutions targeted to different mission scenarios as mega-constellations [21], SmallSats in Low Earth Orbit (LEO) [22], and interplanetary CubeSats [23] have been recently proposed. Following this trend, the usage of plasma discharge cells in a programmable reflective surface has been proposed [24,25]. ...
Gaseous Plasma Antennas (GPAs) exploit an ionized gas to transmit and receive electromagnetic waves. GPAs offer several advantages over metal antennas since, while in use, they are electronically reconfigurable in terms of radiation pattern and operation frequency. When not used, the plasma can be turned ‘‘off’’, and the GPA reverts to a dielectric tube with a very low radar cross-section. This makes GPAs suitable to be stacked into arrays, providing they can reduce co-site interference. Thus, GPAs are very appealing for Satellite Communications (SatCom). The antenna pointing and tracking obtained by steering the beam electronically, rather than using mechanically moving parts, can enable several space missions. A plasma-based reflective
surface has been recently proposed in this framework to maximize reconfigurability. Such a device consists of many plasma discharges placed on top of a metallic ground plane, and the reflection of radio signals can be controlled by electronically varying the plasma properties (e.g., density). This work presents the first step toward practically implementing a plasma-based reflective surface in the X-band capable of electrically, rather than mechanically, tuning its beam steering and focusing capabilities. The study here presented combines numerical and experimental approaches. First, a target plasma discharge has been characterized experimentally to provide the plasma parameters needed to estimate the electromagnetic (EM) response using numerical simulations. Then, the numerical simulations were performed to preliminary design a plasma-based reflective surface. At first, a simplified single-element plasma cylinder was analysed. Then, the glass envelope needed to contain the plasma was added to the column, and its impact on the performance was evaluated. Finally, a finite surface of ten plasma cylinders (including glass vessels) has been considered. The preliminary results prove the capability to obtain beam-steering by tuning the plasma density within the discharges.
A constellation consisting of more than one thousand LEO satellites has been proposed in China in recent years. The purpose of this constellation is to provide an effective solution for space-based multimedia networks all over the world. The operational orbit is roughly defined as follows. Altitude is about one thousand kilometers, the inclination is about 90 degrees, and tens of orbit planes are designed for satellites to deploy in space. The space environment for satellites in such orbit altitude is particularly focused on to carry out such a huge space engineering successfully. Herein, such radiation causes as the Earth radiation belt, solar proton, and cosmic ray are considered. Based on internationally advanced space environment assessment software, SPENVIS, with the novelty of a multimedia network deployed at 1000 km altitude, the practical constraints to be suitable for tough space environment situations are simulated. Based on radiation simulations, it has shown that if the 7-year lifespan for LEO satellites is concerned, there is about 50.4 krad radiation dosage after 3mm Aluminium shielding; there is about 20.9 krad dosage with 6mm Aluminium shielding; and there is about 16.5 krad dosage with 9mm Aluminium shielding. Considering the design margin for radiation dosage, for 7-year lifespan satellites, the anti-total dose capacity is about 50.4×2 krad total dose with 3 mm Aluminium shielding; there is about 20.9×2 krad dosage with 6 mm Aluminium shielding; and there is about 16.5×2 krad total dose with 9 mm Aluminium shielding. If only the above space environment requirements are met, the proposed multimedia constellation would be in operation safe and sound in space during the lifespan of the satellites in question.
Metasurfaces have shown unparalleled controllability of electromagnetic (EM) waves. However, most of the metasurfaces need external spatial feeding sources, which renders practical implementation quite challenging. Here, a low‐profile programmable metasurface with 0.05λ0 thickness driven by guided waves is proposed to achieve dynamic control of both amplitude and phase simultaneously. The metasurface is fed by a guided wave traveling in a substrate‐integrated waveguide, avoiding external spatial sources and complex power divider networks. By manipulating the state of the p‐i‐n diodes embedded in each meta‐atom, the proposed metasurface enables 1‐bit amplitude switching between radiating and nonradiating states, as well as a 1‐bit phase switching between 0° and 180°. As a proof of concept, two advanced functionalities, namely, low sidelobe‐level beam scanning and Airy beam generation, are experimentally demonstrated with a single platform operating in the far‐ and near‐field respectively. Such complex‐amplitude, programmable, and low‐profile metasurfaces can overcome integration limitations of traditional metasurfaces, and open up new avenues for more accurate and advanced EM wave control within an unprecedented degree of freedom.
