Reconfigurable Reflectarray Antenna Research Articles

Low-Scattering and Dual-Polarized Reconfigurable Reflectarray Antenna Based on Absorptive and Active Coding Metasurfaces

Low-Scattering and Dual-Polarized Reconfigurable Reflectarray Antenna Based on Absorptive and Active Coding Metasurfaces

A High Aperture Efficiency 1-bit Reconfigurable Reflectarray Antenna With Extremely Low Power Consumption

A High Aperture Efficiency 1-bit Reconfigurable Reflectarray Antenna With Extremely Low Power Consumption

Antena Tatasusun Pantulan Boleh Konfigurasi Semula: Latar Belakang, Klasifikasi dan Mekanisme Boleh Konfigurasi

Reflectarray antennas have emerged as one of the most suitable choice for 5G network base station antennas due to their ability to combine the advantages of parabolic reflectors and phased array antennas. These antennas offer a lightweight structure, high gain, and low impedance mismatch losses. High gain and low loss are crucial factors in ensuring the antenna delivers low latency and high-quality 5G radio signals. The application of 5G technology becomes more practical and efficient with the capability to adjust the functionality of a single 5G antenna or enable reconfiguration. This reconfigurable technique simplifies the multi-antenna systems and significantly reduces costs, making it more practical and systematic. Furthermore, this reconfigurability is particularly beneficial for satellite applications, as it allows for the reconfiguration of the signal in the event of satellite movement on the space. This paper aims to discuss the historical development of reconfigurable reflectarray antennas, focusing on the innovations in each configurable mechanism. The paper further explores the classification of configurations employed by this antenna, encompassing frequency configuration, radiation pattern, polarization, and hybrid configurations that integrate multiple existing configuration classifications. Finally, the research paper provides a discussion of the most recent research and innovations in the configurable mechanisms of reflectarray antennas.

A 1-Bit All-Metal Wide-Angle and Multipolarization Beam-Scanning Reconfigurable Reflectarray Antenna

In this letter, a 1-bit wide-angle and multi-polarization beam-scanning reconfigurable reflectarray antenna (RRA) is designed, fabricated and measured. The proposed RRA element consists of a square base, a circular turntable and three butterfly staircases with different heights based on 3D all-metal structure. The 1-bit reflected phase and orthogonal linear polarization reconfigurability can be achieved by rotating the proposed RRA element. Then, an all-metal RRA prototype with 26 × 26 rotational elements are fabricated, which is fed by a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -polarized corrugated horn with 20° inclination. The multi-polarization scanning beams are generated by dynamically rotating individual element on the aperture. The measured results show that the RRA prototype can achieve a 60° beam scanning with maximum scan loss of 3.3 dB in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -polarization, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarization and circular polarization at 10.0 GHz. The peak gains of 27.2 dBi, 26.7 dBi and 27.1 dBi with aperture efficiency of 24.7%, 22.0% and 24.2% are obtained where the 1-dB gain bandwidth is 24.0%, 14% and 18% for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -polarization, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarization and LHCP. The proposed RRA greatly reduces the cost, complexity and RF loss.

A liquid metal based 1-bit reconfigurable reflectarray antenna for beam-scanning applications

In this letter, a 1-bit reconfigurable reflectarray antenna (RRA) using liquid metal with high gain, high aperture efficiency is proposed to realize beam steering. The reflectarray element consists of three layers: the top and bottom layers both have a translucent resin casing with one thin dielectric layer in between. The top layer is a square ring structure while the bottom layer is a complementary structure to the top layer with four channels. The middle layer is a thin dielectric layer for supporting top and bottom layers. The 1 bit state of RRA means the top casing is filled with liquid metal while the bottom casing is the air, otherwise means 0 bit states. The phase difference between two states is nearly 180°which is suitable for designing 1 bit RRA. Finally, a 20×20 reflectarray is designed, simulated and measured to validate the performance. Both simulated and measured results show that the proposed liquid metal based RRA can effectively generate scanning beams within ±40°and the maximum measured gain is 24.08dBi with aperture efficiency of 20.36%. The proposed RRA is compact and has structural flexibility using liquid metal, which can be applied in modern wireless communication systems.

A metal-only reconfigurable reflectarray antenna for generating diversified circular-polarization focused beams and mode-agile vortex beams

ABSTRACT In this article, a metal-only reconfigurable reflectarray antenna (RRA) is proposed for generation of diversified circular-polarization (CP) focused beams and mode-agile vortex beams in the X-band. The proposed RRA element has the 3-D metal-only configuration, which consists of three staircases with different heights, a turntable, a latch, and a base. By rotating the proposed RRA element in 45° steps, the ability of 1-bit phase quantization with orthogonal linear polarization (LP) reconfigurability can be realized. Then, a 26 × 26-elements reconfigurable reflectarray antenna feeding by a linear polarization horn antenna is designed to enable free conversion of line-to-circle polarization at the array level. Full-wave simulations show that the diversified circular-polarization beams can be synthesized by adjusting the aperture element distribution. Furthermore, a manually reconfigurable reflectarray antenna prototype is fabricated to obtain the actual performance of the synthetic LHCP focused beams. The measured maximum gain of the LHCP beams is 27.1 dBi, with the aperture efficiency of 24.2% where the beam point at 20°, and the 1-dB gain bandwidth is 18.0% (9.3 GHz − 11.1 GHz). Finally, mode-agile vortex beams can also be realized by using the proposed reconfigurable reflectarray antenna, and the simulated results show that the mode purity of vortex beams are all above 35% in different modes, and the maximum gain of the vortex beams is 21.1 dBi, with aperture efficiency of 6.1% where the mode of vortex beams is −1.

Is It Possible to Design a 1-Bit Reconfigurable Transmitarray Element With a Single Switch?

With the rapid development of reconfigurable transmitarray antennas (RTAs), a lot of antenna prototypes have been proposed in literatures. It is noticed that all 1-bit RTA elements utilize at least two switches to realize 1-bit transmission phase difference. Hence, a question arises: Is it possible to design a 1-bit reconfigurable transmitarray element with a single switch? In this letter, three-port network theory is employed to prove that a single-switch RTA element CANNOT realize both high transmission efficiency and 1-bit phase tuning ability simultaneously. Furthermore, we also prove that it is impossible to realize a 1-bit reconfigurable reflectarray antenna (RRA) element with polarization conversion that uses only one switch. However, based on two-port network equivalence, a 1-bit RRA element without polarization conversion is possible by using a single switch.

Electronically Controlled Frequency Agile Beam Scanning Reflectarray Antenna with Integrated Control Unit

This paper reports the design, development, fabrication, and testing of a 225-element reconfigurable reflectarray (RRA) antenna with frequency agility and beam steering capabilities. The 15 15 (18.75 cm) RRA operating in the Ku band downlink frequency range (11.8 -12.2 GHz) of fixed satellite services (FSS) produces dual resonances switched between uplink frequency range (15-18 GHz) of FSS and earth exploration satellite range of 9.5-9.8 GHz (X Band). To attain reconfigurable multiple resonances, the unit cell is designed with a Malta cross of varying slot lengths interconnected to a square ring via a PIN diode. In the OFF state of the PIN diode connected between the concentric elements, a phase variation of 360° is obtained at 12 GHz and 9.5 GHz by varying the size of the Malta cross. By increasing the width of the outer ring in the ON state of the PIN diode, a dual resonance is obtained at 12 GHz and 17 GHz with 360° phase agility. The beam scanning is attempted at X band frequency by controlling the capacitance offered by the varactor diode connected between an inductive element and Malta cross. The proposed RRA offers 22.16 dBi, 24.5 dBi and 18.43 dBi simulated gain at 17 GHz, 12 GHz, and 9.5 GHz respectively. The simulated sidelobe levels (SLLs) and cross-polarization levels are -14.7 dB and less than -32 dB respectively. The proposed compound reconfigurable reflectarray befits fixed and mobile satellites, earth exploration satellites, radiolocation, aeronautical radio navigation, and deep space research.

Dual-Layer Beamscanning Reflectarray Antenna Operating at Ku-Band

This paper presents a beam scanning electronically reconfigurable reflectarray configuration for Ku-band applications using a single varactor diode. A 15×15 center-fed reconfigurable reflectarray antenna is designed consisting of 225 octagonal shaped unit cells. The proposed tunable element has a unit cell size of 9.8 mm, developed on a 1.575 mm thick Taconic TLY-5 substrate. A single varactor diode is integrated with the tunable element to produce a reflection phase variation of 340° at 14.1 GHz. In this work, both the varactor and biasing circuit are placed beneath the substrate to avoid unexpected reflections, which leads to achieving a pencil beam of 8.1° beamwidth. The simulation results of the reconfigurable reflectarray antenna (RRA) shows good beam-scanning radiation performance of scanning range ±30° and a peak gain of 27.6 dBi. This structure provides a convenient solution for Ku-band distinctive applications like uplink operation in the direct broadcast satellite system, digital video broadcasting, earth exploration satellites, space research satellites, and defense systems.

A Broadband 1-Bit Single-Layer Reconfigurable Reflectarray Unit Cell Based on PIN Diode Model

Microstrip reconfigurable reflectarray antennas (RRAs) have great potential for advanced systems including satellite communications and the 6th generation (6G) wireless mobile communication networks. However, as a type of microstrip antennas, RRAs generally exhibit an intrinsic issue of narrow bandwidths. This issue is further deteriorated by complicated structures for phase shifting and DC supplying in RRAs. PIN diodes have been used in recent works to control the phases of RRA elements. However, modelling them is still costly and time consuming. In this work, a simple but novel method for modelling PIN diode SMP-1340-040 is developed by using waveguides and modified simulation approaches. Based on the obtained model, a broadband 1-bit unit cell using only one substrate is also proposed, and it achieves a simulated bandwidth of 40.6% and 33.8% for linear and circular polarizations, respectively. The experimental results show an excellent agreement with the simulation, which confirms the accuracy of the proposed PIN diode model. Moreover, the performances of the unit cell demonstrate that it can be used for designing RRAs in bands X and Ku.

A Wideband Low-Cost Reconfigurable Reflectarray Antenna With 1-Bit Resolution

A wideband 1 bit reflectarray antenna (RA) with two-dimensional (2-D) electronically beam-scanning capability is presented in this article. Based on the basic structure of the magnetoelectric (ME) dipole antenna, a novel reconfigurable RA (RRA) element is proposed for wideband operation by combining electric dipole resonance and magnetic dipole resonance. Each element is integrated with only one p-i-n diode to change the types of resonances, leading to a reconfigurable reflecting phase with a 1 bit resolution. As a demonstration, a wideband electronically RRA with 16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times16$ </tex-math></inline-formula> elements is developed, fabricated, and measured. In the proposed RRA, each element is connected with a separate bias line to independently control the working state and reflecting phase. Measured results show that the proposed RRA can achieve a 3 dB gain bandwidth of 38.4% with a peak aperture efficiency of 24% at 12 GHz. Besides, the proposed antenna can support the wide scanning angles ranging from – 60° to + 60° in the E-plane and 0° to + 60° in the H-plane within the whole operating bandwidth. The proposed simple design could be a promising candidate for intelligent reflective surface (IRS) applications.

Reconfigurable Reflectarray Antenna Based on Hyperuniform Disordered Distribution

The irregularly located element array within the antenna aperture can be applied to obtain narrow main lobe width and low sidelobe levels with fewer elements as compared with the traditional (periodic) array configurations. In this article, a reconfigurable reflectarray antenna (RRA) combined with hyperuniform disordered distribution is presented. Based on the theoretical radiation pattern of reflectarray, it has been found that the proposed array with reduced elements holds a similar radiation pattern as that of a corresponding periodic array. Meanwhile, the reflectarray avoids the design of complicated feeding network for the disordered phased array antenna. In addition, for a reconfigurable reflectarray to achieve beam scanning, active devices are necessary. In such case, the design of RRA with fewer elements is of particular importance. A 1 bit RRA of 64 elements prototype has been designed, fabricated, and measured. The side length of each element is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.625\lambda $ </tex-math></inline-formula> . Experimental results agree well with the full-wave simulations, and scan beams within ± 50° range have been obtained with a peak gain of 17.4 dBi at 12.5 GHz.

A Wideband 1-Bit Reconfigurable Reflectarray Antenna at Ku-Band

In this letter, a wideband high-efficiency 1-bit 16 × 16 reconfigurable reflectarray antenna (RRA) is proposed. First, a wideband and low loss 1-bit RRA element is designed. It consists of double-layer patches printed on two dielectric substrates, respectively, forming a multiresonant behavior to expand the bandwidth.Due to the relatively thin thickness of the double-layer dielectric substrate (0.05 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ), the element has low reflection loss. Therefore, the high efficiency and wide bandwidth performances can be obtained simultaneously. The phase difference between the two states of the RRA element is stable within 180 ± 20° in the frequency range of 12.9–16.5 GHz. Based on the broadband RRA element, a 16 × 16 RRA was fabricated and measured. Tested results show that the proposed RRA achieves 22.5% of 1 dB gain bandwidth and 25% of maximum aperture efficiency.

Circularly Polarized One-Bit Reconfigurable ME-Dipole Reflectarray at X-Band

In this letter, a broadband and low loss circularly polarized (CP) electronically reconfigurable reflectarray antenna (RRA) that can operate over the X-band is reported. The proposed RRA invokes a new reconfigurable magneto-electric (ME) dipole based element for dynamically manipulating the phase of the back-scattered CP wave from each pixel, and hence, the direction of the reflected beam. The engineered wideband ME-dipole element and the design of a low loss reconfigurable perturbation structure contribute jointly to a superior CP bandwidth as well as a high efficiency. A reflectarray prototype with two-dimensional (2-D) beam scanning is designed, fabricated, and measured, demonstrating a wide-angle beam scanning capability. Besides, notable advances in bandwidth and aperture efficiency of the 1-bit CP RRA are identified, over the previous state of the art.

Ka-Band Reconfigurable Reflectarrays Using Varactor Technology for Space Applications: A proposed design

In this article, Ka-band reconfigurable reflectarray antennas based on varactor diodes are investigated. Varactor diodes enable high radiation pattern flexibility while maintaining acceptable costs. The design of a dual-band reconfigurable reflectarray based on varactor technology is described in detail. The antenna, considered for a fixed or mobile ground station for satellite telecommunications systems, could be used for several other applications. To demonstrate and validate experimentally the proposed concept, the design of a reduced-sized antenna is presented. The manufacturing and testing of its reconfigurable reflecting surface are then described and discussed. This antenna design could also be considered as a baseline for a data downlink antenna employed on a satellite.

A Wide-Angle and High-Efficiency Reconfigurable Reflectarray Antenna Based on a Miniaturized Radiating Element

A wide-angle reconfigurable reflectarray antenna (RRA) was designed and experimentally verified utilizing a miniaturized ring patch efficiently controllable with a single bit. Based on the merits of the miniaturization of the radiating element and an elaborate study of the quantization efficiencies of the asymmetric phase differences between the on/off states of the unit cell by optimizing a reference phase on the metasurface, highly directive beam scanning is achieved in a wide ±60° range in both the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -planes. Furthermore, the illumination and spillover efficiencies and focal diameter ratio (F/D) are carefully optimized, resulting in a low profile configuration with F/D=0.36. The fabricated RRA prototype was measured at 9.85 GHz (X-band) with the highest aperture efficiency of 28% and a 1 dB gain bandwidth of 530 MHz, respectively.

Mechanically Reconfigurable, Beam-Scanning Reflectarray and Transmitarray Antennas: A Review

We review mechanically reconfigurable reflectarray (RA) and transmitarray (TA) antennas. We categorize the proposed approaches into three major groups followed by a hybrid category that is made up of a combination of the three major approaches. We discuss the examples in each category and compare their performance metrics including aperture efficiency, gain, bandwidth and scanning range and resolution. We also identify opportunities to build upon or extend these demonstrated approaches to realize further advances in antenna performance.

Vortex Beam Generation Based on Plasma Reflect- Array Surface at Microwave Frequencies

Orbital angular momentum (OAM) is a promising feature of electromagnetic (EM) wave to increase the communication link capacity. It is possible to use the OAM over the whole spectrum from radio frequency to optic. EM waves would experience a vortex phase boundary while transmitting the data. According to the infinite number of vortex modes, there would be infinite data transmission in theory. Here, a plasma medium with a complex structure is exploited to construct the vortex phase plane at microwave frequencies. Plasma as the ionized gas transmits, reflects, and absorbs EM wave under some conditions. The ratio of plasma physical parameters with the impinging wave frequency presents the condition of wave interaction with the plasma medium. A reflector plane is realized with the help of multilayered low-pressure plasma. By radiation of a plane wave toward the reflector surface, vortex beams of several modes are realized. The controllability of plasma electron frequency makes it a reconfigurable reflect-array antenna for vortex beam generation. The design is based on the scattering theory of the dielectric plasma model for a vast frequency of 8-16 GHz. The proposed advanced EM structure to generate the vortex beams is simulated with a full-wave analysis that verifies the studied design.

Fully Electronically Phase Modulation of Millimeter-Wave via Comb Electrodes and Liquid Crystal

This letter presented a nematic liquid crystal (LC) based metal-dielectric-metal structure to fully electronically modulate the reflection phase of electromagnetic waves. The demonstrated structure is composed of a thin LC layer sandwiched between copper comb electrodes and a single slotted reflection array. Based on a proper application of the external electric field, the whole process of nematic LC molecular orientation is controlled. The innovative feeding method can actively prealign and deflect the orientation of LC molecules. Experimental results show that the maximum reflection phase shift is 189.2° at 114.9 GHz. This letter provides a practical way of regulating LC-based terahertz devices. The proposed structure is a potential candidate for the reconfigurable reflectarray antennas.

Accurate Characterization of Graphene Reconfigurable Reflectarray Antenna Element by SVR

The analysis of the graphene reconfigurable reflectarray antenna electromagnetic (EM) response through the use of support vector regression (SVR) has been carried out in this paper. The EM response of the original graphene reflectarray antenna is transformed into a regression estimation problem by SVR. In this work, we consider up to 6 degrees of freedom: the width W and length L of the graphene patch, the graphene chemical potential μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> , the working frequency f, and the elevation θ and azimuth angles φ of the incident field. Firstly, they are discretized separately, and then full-wave (FW) simulation software is used to calculate the reflectarray antenna unit cell under different parameters to obtain the training data set of SVR. Finally, SVR is used to obtain an alternative model of the graphene reconfigurable reflectarray antenna unit cell, which is used to quickly predict the scattering coefficient matrix in co-polarized and cross-polarized states. Through the comparison of SVR method with the radial basis function network (RBFN) and FW simulation results, the effectiveness of the proposed method in precision and efficiency is verified.