Reconfigurable Reflectarray Research Articles

A Study on a Compact Double Layer Sub-GHz Reflectarray Design Suitable for Wireless Power Transfer

The paper presents a novel small-footprint varactor diode-based reconfigurable reflectarray (RRA) design and investigates its power reflection efficiency theoretically and experimentally in a real-life indoor environment. The surface is designed to operate at 865.5 MHz and is intended for simultaneous use with other wireless power transfer (WPT) efficiency-improving techniques that have been recently reported in the literature. To the best of the authors’ knowledge, no RRA intended to improve the performance of antenna-based WPT systems operating in the sub-GHz range has been designed and studied both theoretically and experimentally so far. The proposed RRA is a two-layer structure. The top layer contains electronically tunable phase shifters for the local phase control of an incoming electromagnetic wave, while the other one is fully covered by metal to reduce the phase shifter size and RRA’s backscattering. Each phase shifter is a pair of diode-loaded 8-shaped metallic patches. Extensive numerical studies are conducted to ascertain a suitable set of RRA unit cell parameters that ensure both adequate phase agility and reflection uniformity for a given varactor parameter. The RRA design parameter finding procedure followed in this paper comprises several steps. First, the phase and amplitude responses of a virtual infinite double periodic RRA are computed using full-wave solver Ansys HFSS. Once the design parameters are found for a given set of physical constraints, the phase curve of the corresponding finite array is retrieved to estimate the side lobe level due to the finiteness of the RRA aperture. Then, a diode reactance combination is found for several different RRA reflection angles, and the corresponding RRA radiation pattern is computed. The numerical results show that the side lobe level and the deviation of the peak reflected power angles from the desired ones are more sensitive to the reflection coefficient magnitude uniformity than to the phase agility. Furthermore, it is found that for scanning angles less than 50°, satisfactory reflection efficiency can be achieved by using the classical reactance profile synthesis approach employing the generalized geometrical optics (GGO) approximation, which is in accord with the findings of other studies. Additionally, for large reflection angles, an alternative synthesis approach relying on the Floquet mode amplitude optimization is utilized to verify the maximum achievable efficiency of the proposed RRA at large angles. A prototype consisting of 36 elements is fabricated and measured to verify the proposed reflectarray design experimentally. The initial diode voltage combination is found by applying the GGO-based phase profile synthesis method to the experimentally obtained phase curve. Then, the voltage combination is optimized in real time based on power measurement. Finally, the radiation pattern of the prototype is acquired using a pair of identical 4-director printed Yagi antennas with a gain of 9.17 dBi and compared with the simulated. The calculated results are consistent with the measured ones. However, some discrepancies attributed to the adverse effects of biasing lines are observed.

Design of a 3-Bit Circularly Polarized Reconfigurable Reflectarray

In this paper, a 3-bit circularly polarized reconfigurable reflectarray is proposed. The array consists of 64 units in an 8 × 8 configuration, with each unit containing a circular metal patch loaded with phase-delay lines and eight PIN diodes. To independently control each unit, a corresponding DC control circuit was designed and tested with the array. In the bandwidth of 3.43–3.71 GHz, the circularly polarized reconfigurable reflectarray achieved a gain of 16 dB, an aperture efficiency of 27%, an axial ratio of ≤3 dB, an operating bandwidth of 8%, and a beam scanning range of ±60°. The circularly polarized reconfigurable reflectarray can also achieve a good dual-beam radiation performance after testing. The 3-bit circularly polarized reconfigurable reflectarray proposed in this paper offers several advantages, including low loss, high aperture efficiency, a wide beam scanning range, and excellent stability in wide-angle oblique incidence. It has potential applications in low-cost phased array, satellite communications, and deep space exploration.

Dual-polarized bidirectional beam-steering array with beam-scanning capability in full-space

This paper presents a dual-polarized bidirectional electronically reconfigurable beam-steering array (DBSA) for the first time, which integrates the beam-scanning capabilities of both dual-polarized reconfigurable transmitarray and dual-polarized reconfigurable reflectarray. First, a novel phase and direction reconfigurable dual-polarized element is proposed. Four PIN diodes are soldered onto the symmetric transmitting patches to tune the 1-bit transmission phase, while two PIN diodes are soldered onto the reflecting patches to tune the 1-bit reflection phase. By controlling the states of the PIN diodes, the DBSA element can achieve 1-bit reconfigurable phase in both transmission and reflection modes. Second, based on the proposed element, a 100-element DBSA prototype is fabricated and measured. At dual-polarization, the angles of the scanned beams can reach 45∘ and 222∘ in forward- and backward-spaces. Therefore, the proposed novel method opens a new avenue to designing a dual-polarized electronically reconfigurable spatially fed array antenna with full-space beam-scanning capabilities, and the proposed design is suitable for dual-polarized bidirectional wireless communication applications.

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

Design of a 2-bit Dual-Polarized Reconfigurable Reflectarray With High Aperture Efficiency

Design of a 2-bit Dual-Polarized Reconfigurable Reflectarray With High Aperture Efficiency

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 Dual-Band Beam-Steering Array Antenna With Integration of Reflectarray and Phased Array

This letter presents a dual-frequency beam steering array antenna (DBSA), which integrated a height adjustable reconfigurable reflectarray of C-band and a phased array of X-band. Each antenna element can achieve an arbitrary phase shift value in the range of 0° to 360° by controlling the height-adjustable device and digital phase shifter at 5.8 GHz and 10 GHz, respectively. Accordingly, the DBSA can be fed by two sets of feed networks independently, which can simultaneously achieve beam steering of arbitrary angle at dual frequencies. A prototype of 8 × 8 DBSA was designed and fabricated to realized beam scanning in the angle range from -40° to 40° in the XOZ plane at 5.8/10 GHz respectively. The measured maximum gain of DBSA is 14.4/21 dBi with aperture efficiency of 32.9% / 50.6% at 5.8/10 GHz respectively. The proposed DBSA can be applied in satellite communication to realize air-to-ground and inter-satellite communications at the same time.

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.

One‐bit wideband reconfigurable reflectarray with stable beam‐scanning gain for X‐band application

AbstractA wideband and electrically reconfigurable reflectarray (RRA) is presented for X‐band application. The unit cell is composed of two heterogeneous resonators, that is, a split resonator ring and a metallic patch, and two positive‐intrinsic‐negative (PIN) diodes integrated between these two resonators. A bias circuit on the bottom layer is designed to achieve the switching of the two states via properly placing the PIN diodes on the resonators with minimal electric field. One‐bit phase quantization is obtained by switching two different resonant mode via controlling the ON or OFF state of two PIN diodes. The simulated results show that the proposed unit cell can achieve one‐bit phase quantization with 180° ± 20° and reflection coefficients of ‐1 dB from 9.5 to 10.8 GHz, corresponding relative bandwidth of 12.81%. In addition, a fully functional 12 × 12 RRA fed by a linearly polarized horn is theoretically designed, simulated, and fabricated. The measured results show that the main beam can be steered from −50° to +50° at operating frequency, for example, 10.1 GHz with 1.5 dB gain loss within the scanning range and 20.34% aperture efficiency. In addition, the measured average gain is about 17.5 dBi and 3 dB gain bandwidth is about 15.68% from 9.4 to 11 GHz. In virtue of wide bandwidth, stable radiation gain, and good beam scanning capability, the proposed RRA is promising for future wireless communication and radar.

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.

Toward High-Power Beam-Steerable Reflectarrays Using Tunable-Height Dielectric

A novel method for a high-power reconfigurable reflectarray (RRA) with a moderate 30° beam scanning is demonstrated. The proposed technique eliminates the need for mechanical steering of reflectors for satellite communication. A small mechanical movement of a patterned dielectric structure under multislot elements achieves beam steering by changing the coupling. Due to the unique shape of the multislot element, the unit cell is capable of tuning the phase for both linear polarization and circular polarization (CP) within a single design operating at 20 GHz. The maximum phase range obtained in this design is a continuous 280° for RHCP, LHCP, and two linear polarizations at 20 GHz. The phase of the reconfigurable unit cell is verified and measured using a waveguide simulator attached to a micromotor. Maximum element loss is simulated to be 0.5 dB. To demonstrate beam steering, three reflectarrays with frozen dielectrics and square array lattices composed of 400 elements ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\lambda _{0}\,\,\times 10\lambda _{0}$ </tex-math></inline-formula> ) are fabricated. The frozen reflectarrays demonstrate beams at 0°, 15°, and 30°. The measured gain is found to be 23.2 dB at broadside with 21.8 and 23.3 dB, respectively, when scanned to 15° and 30°. The 1 dB gain bandwidth is measured to be 7.45% with a 3 dB axial ratio bandwidth of 12.1%. Unlike other architectures that use nonlinear semiconductor devices, the proposed reflectarray uses a dielectric insert with a height that can be controlled by a micromotor suitable for high-power applications supporting up to 80 MW/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{2}$ </tex-math></inline-formula> .

Polarization and Frequency Reconfigurable Antenna using Metasurface: Analysis, Review and Proposal

Wireless communication technology experienced drastic developments during the last few decades. Meanwhile the reconfigurable antenna had attracted more researchers because of its growing needs in various applications. Reconfiguration was performed to replace numerous antennas with single reconfigurable antenna which is capable of changing the Frequency, Polarization, Radiation Pattern etc. Antenna reconfigurability is attained by deploying several switching mechanisms among them electronic switching mechanisms are commonly used because of its simple integration, reliability, and efficiency. In this paper, review of various implementation techniques for antenna reconfiguration using meta surface are studied. Some of the reviewed factors are: Meta surface is the distribution of electrically small scatters called two-dimensional metamaterial. Metamaterial is an artificially built periodic array structure which consists of subwavelength cells. Some of the reviewed challenges in reconfiguration of the antenna are modeling of reconfigurable reflectarray, low-profile, high gain, unidirectional radiation pattern etc. Finally, some of the features, parameters and fundamental properties for designing reconfigurable antenna were investigated. Based on the study conducted, reconfigurable structure for 5 G application using meta surface is proposed.

Design and Development of Frequency Agile Reflectarray Antenna

This paper presents the design of a frequency reconfigurable reflectarray with concentric circular rings. The PIN diode connected between a phase delay line and the ring produces reconfigured resonances at 16 GHz and 10.4 GHz. The variation in the size of the concentric rings offer a phase change of 356º during the OFF state of the PIN diode. 360° phase variation in the PIN ON condition is achieved by varying the delay line length. A 225-element centre-fed reflectarray antenna is constructed with square geometry. A simulated gain of 23 dBi is obtained with -17 dB side lobe level and -28 dB cross-polarization level at 16 GHz. In the PIN ON condition, a simulated gain of 22 dBi is obtained with -12 dB side lobe level and -28 dB cross polarization level. This reconfigurable reflectarray finds its applications in space research, satellite communication, and RADAR.

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.

Optimum Design of a Novel Electronically Reconfigurable Reflectarray Antenna for X/Ku Band Applications

The frequency reconfigurable reflectarray (RRA) reported in this paper provides a pencil beam at three frequencies captivating the need for satellite broadcast television at uplink and downlink frequencies in Ku band and X band. To achieve such frequency reconfiguration, a unit cell developed and simulated based on an infinite array approach is used in integration with four PIN diodes to produce a reflection phase variation of 525°, 415°, and 308° at 14.34 GHz for uplink operation, 12.2 GHz for downlink and 11.9 GHz for X-band performance respectively. In this proposed unit cell, the phase variation for uplink is achieved by varying the size of concentric loops, while in the case of downlink and X-band, reconfiguration controlled by pin diodes is achieved by varying the length of the delay line. With the periodicity of 0.49λ0 (10.5 mm), a 15 15 array with 225 elements is constructed using the designed unit cell on square planar geometry. The paper reports a maximum gain of 25.77 dBi, 25.13 dBi, and 22.7 dBi and 40.22%, 26.46%, and 25.36% of aperture efficiency at 14.34 GHz, 12.2 GHz, and 11.9 GHz respectively. A -3dB gain bandwidth of 8.37%, 4.92%, and 12.18% is achieved at the three operating frequencies by simulation. Hence this reconfigurable reflectarray serves as an emulous alternative to parabolic reflectors and phased array antennas in deep space communication and direct broadcast satellite applications satisfying the high gain pencil beam requirements.

Novel 1-Bit Beam-Scanning Reflectarray With Switchable Linear, Left-Handed, or Right-Handed Circular Polarization

This article proposes a novel reconfigurable reflectarray (RRA) with 1 bit beam scanning and switchable linear, left-handed (LH) circular, or right-handed (RH) circular polarization. To realize a multipolarization switchable RRA fed by a horn of arbitrarily fixed polarization, the unit cell’s reflection phases in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$y$ </tex-math></inline-formula> -directions are independently controlled to meet the required differential phase in each state. Explicit reflection-phase relation will be given for switching from one polarization to another while fulfilling the 1 bit beam scanning. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times 10$ </tex-math></inline-formula> RRA was prototyped with each unit cell using only two p-i-n diodes to implement dual functions. The fabricated RRA was tested and it can experimentally demonstrate 2-D beam scanning and polarization switching among 45°/135° linear polarization and LH/RH circular polarization. In circular polarization, the measured peak gain, aperture efficiency, and 1 dB gain bandwidth are 17.2 dBic, 26%, and 8.2%, respectively. In linear polarization, the measured cross-polarization discrimination (XPD) of greater than 15 dB, peak gain of 16.8 dBi, aperture efficiency of 23.9%, and 1 dB bandwidth of 5.3% are obtained.