A Foldable and Reconfigurable Monolithic Reflectarray for Space Applications

A novel foldable and reconfigurable reflectarray antenna (RA), operating at 8.425GHz for deep space communications based on an extended Miura-Ori origami pattern is presented. The aperture leverages the properties of subdivision and a folding feature to create a packable and reconfigurable antenna capable of changing its beam from a single pencil beam to a multi-beam aperture with beamsteering ability. A mechanical and theoretical EM analysis is carried out supported by a numerical algorithm using array theory. The results show that the proposed reflectarray can achieve a high packing efficiency of 92%. This RA provides a pencil beam in the broadside at (θ = 0°, ϕ = 0) in its flat configuration and multi-beam (dual, triple and quad-beams) depending on its folding angle. For CubeSat applications, the key advantages of this RA are its decreased stowage volume, reconfigurable EM performance, beamsteering capabilities, low fabrication cost, and reduced complexity.

In this article, we propose an ultralow-power-consumption reconfigurable reflectarray antenna (RRA) capable of wide-angle beam scanning and simultaneous phase, amplitude, and polarization control. The RRA element is integrated with two single-pole single-throw (SPST) switch chips, which achieve 1-bit phase shift and continuous amplitude control for both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i>- and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i>-polarizations. By independently biasing each element, the RRA enables wide-angle electronic beam scanning in both polarization channels. Flexible beam phase control is achieved by adjusting the reference phase in the array factor. The beam amplitude is continuously tuned by precisely controlling the bias voltages of the integrated SPST switch chips. Furthermore, since both the phase and amplitude of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i>- and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i>-polarizations can be modulated, the RRA can synthesize scanning beams with arbitrary polarization. As a demonstration, a 16 × 16 RRA prototype is designed, simulated, and measured. Both simulations and measurements confirm that the RRA can achieve beam scanning over a wide-angle range of ±60°, with a maximum gain of 20.78 dBi and an aperture efficiency of 22.8%. Additionally, its capacities for phase, amplitude, and polarization control are fully demonstrated. Furthermore, the measured maximum power consumption of the RRA is only 0.34 W, corresponding to 1.3 mW per element. With its ultralow power consumption and versatility, the proposed RRA shows great potential for green wireless communications and advanced radar applications.

Reconfigurable reflectarray antenna (RRA) has been considered a potential technology for future communication. However, few studies focus on investigating the intermodulation distortion induced by its active devices, which are employed to provide different compensation phases for the RRA elements. In this paper, the radiation pattern prediction for third‐order intermodulation (IM3) distortion of the RRA with embedded varactor diodes is first proposed. It is implemented with a nonlinear model of the varactor and full‐wave electromagnetism (FEM) simulation. The presented varactor model is first employed to design the RRA and then to acquire the power and phase of the IM3 signal in each element of the RRA, which is realized with a nonlinear harmonic‐balance and FEM co‐simulation. With the help of the HFSS software, the radiation pattern is achieved when the co‐simulation results of the RRA elements are input. The IM3 radiation measurement of the RRA is presented to verify the radiation pattern prediction of the IM3 signal. The consistent comparison results between the simulation and the measurement indicate that the proposed method is accurate. Significantly, the radiation pattern of the IM3 signal is different from that of the fundamental signal based on the designed RRA. It is meaningful and implies that it may have linearization approaches for the RRA. The proposed method will enhance the application of the RRA since the linearization approach is still a scientific challenge in future wireless networks.

An electronically steerable monopulse antenna based on reconfigurable reflectarray antenna (RRA) has been designed, fabricated and tested. The large-scale RRA at X-band is consisted of $160\times 64$ elements integrated with PIN diodes, and is controlled by arrays of 160 field-programmable gate arrays (FPGAs) in parallel, for the steerable monopulse patterns. The steerable sum-difference beams are achieved by the diode state distributions of the RRA. The gain of the RRA is measured to be 37.35dBi, and the null-depth is measured to be -43.51dB at the direction angle of 0 o. A null-depth of under -37.54dB is verified at the direction angle of 60°. The electronically steerable monopulse antenna based on RRA presents a low-cost solution for high resolution tracking applications.

Lamina emergent compliant mechanisms (including origami-adapted compliant mechanisms) are mechanical devices that can be fabricated from a planar material (a lamina) and have motion that emerges out of the fabrication plane. Lamina emergent compliant mechanisms often exhibit undesirable parasitic motions due to the planar fabrication constraint. This work introduces a type of lamina emergent torsion (LET) joint that reduces parasitic motions of lamina emergent mechanisms, and presents equations for modeling parasitic motion of LET joints. The membrane joint also makes possible one-way joints that can ensure origami-based mechanisms emerge from their flat state (a change point) into the desired configuration. Membrane-enhanced LET (M-LET) joints, including one-way surrogate folds, are described here and show promise for use in a wide range of compliant mechanisms and origami-based compliant mechanisms. They are demonstrated as individual joints and in mechanisms such as a kaleidocycle (a 6R Bricard linkage), degree-4 origami vertices (spherical mechanisms), and waterbomb base mechanisms (an 8R multi-degrees-of-freedom origami-based mechanism).

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.

Terahertz reconfigurable reflectarray antennas (RRAs) hold significant promise for next-generation wireless communication systems by enabling dynamic beam control to mitigate severe path loss at high frequencies. This work presents a Complementary Metal-Oxide-Semiconductor (CMOS)-based RRA for terahertz amplitude control using tunable split-ring resonators. First, a terahertz switch in standard 65 nm CMOS process is designed, tested, and calibrated on the chip to extract the equivalent impedance, enabling precise RRA element design. Next, a reconfigurable element architecture is presented through the co-design of a split-ring radiator, control line, and a single switch. Experimental characterization demonstrates that the fabricated RRA achieves 3 dB amplitude variation at 0.290 THz with &lt;8.5 dB element loss under 0.8 V gate bias. The measured results validate that the proposed single-switch topology effectively balances reconfigurability and loss performance in the terahertz regime. The demonstrated CMOS-compatible RRA provides a scalable solution for real-time beamforming in terahertz communication systems.

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

A folded reconfigurable reflectarray antenna for mono-pulse radar application is presented in this paper. The proposed antenna combines the properties of reconfigurable reflect-array antenna and folded reflectarray antenna. A reconfigurable reflectarray with $15\times 15$ elements is developed to verify the design method. The antenna design is calculated and simulated using MATLAB and HFSS, and detailed results are presented and discussed. The reconfigurable reflectarray antenna can operate at Ku-band and provide the performance of beam scanning. This reconfigurable reflectarray antenna has significant potential for satellite applications, due to its low profile, simple control and beam-scanning capability.

Small-scale flexible (or compliant) mechanisms are valuable in replacing rigid components while retaining comparable motion and behavior. However, fabricating such mechanisms on this scale (from 0.01 to 10 cm) proves difficult, especially with thin sheet metals. The manufacturing method of laser forming, which uses a laser to cut and bend metal into desired shapes, could facilitate this fabrication. However, specific methods for designing mechanisms formed by lasers need to be developed. This work presents laser forming as a means for creating compliant mechanisms on this scale with thin sheet metal. The unique challenges for designing mechanisms to be laser formed are explored, and new adaptations of existing designs are fabricated and discussed. The design of basic “building-block” features is developed for several mechanisms: a parallel-guided mechanism, a cross-axis flexural pivot, a lamina emergent torsional (LET) joint array, a split-tube flexure, and a bi-stable switch. These mechanisms are shown to perform repeatable behavior and motion comparable to existing nonlaser-formed versions. The further possibilities for fabricating compliant mechanisms with laser forming are explored, as advanced applications can benefit from using lasers to create compliant mechanisms from thin sheet metal.

Terahertz (THz) high gain antennas with electronic beam-scanning capability have been long required in various modern applications. In this paper, a novel reconfigurable reflectarray antenna (RRA) at 0.3 THz with 16×16 individually controlled 1-bit phasing elements is proposed. The element consists of a shorted bow-tie microstrip patch and a double-channel heterostructure HEMT in the middle. Electronic 1-bit phase control can be achieved by switching the state of HEMT. The element simulation verifies its wideband and low cross-polarization performance. Design and analysis of a RRA with 16×16 elements and practical biasing circuits are presented. The high gain beam scanning capability of the proposed RRA is validated by theoretical calculations.

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.

In this paper, a wideband reconfigurable reflectarray antenna (RRA) using 1-bit resolution for beam scanning with two-dimensional (2D) capability is presented at Ku-band. A 1-bit RRA element with a rectangular patch embedded with slots is proposed for broadband operation. Each element is equipped with a single PIN diode, allowing for resonance tuning while ensuring low cost and minimal power consumption. According to the simulation results, the proposed element is capable of 1-bit phase resolution with a phase difference of ${180^\circ \pm 20^\circ}$ stability from 11.27 to 13.74 GHz, which corresponds to an approximate bandwidth of 19.75%. To demonstrate its capabilities, we developed, fabricated, and tested a wideband electronically RRA with ${14 \times 14}$ elements. The experimental results demonstrate that the realized maximum gain in the broadside direction is 21.1 dB with a peak aperture efficiency of 20.9%. 2D beam scanning within ${\pm50^\circ}$ angular range are obtained and the scan gain reduction is 1.88 dB for ${-50^\circ}$ scanned beam in E-plane while 2.21 dB for ${50^\circ}$ scanned beam in H-plane. The 1-dB gain bandwidth of the RRA is 15.1%.

In 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%.

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.