Ruyuan Deng

A 100-GHz Metal-Only Reflectarray for High-Gain Antenna Applications

A 100-GHz metal-only reflectarray antenna is designed, fabricated, and tested. The required phase shift is achieved by simply tuning the metal block height, aiming to eliminate dielectric losses at high frequencies. An equivalent circuit model is employed to analyze the element reflection performance. A prototype reflectarray with a 30-mm square aperture is then fabricated and tested using near-field measurement setup. The measured results show an aperture efficiency of 50.1% at 100 GHz, and the measured radiation patterns agree very well with the full-wave simulation results. To compare the radiation performances, a parabolic reflector, a Fresnel zone plate reflector, and an unwrapped reflectarray of same size are also evaluated. The full-wave simulation results demonstrate that the proposed design not only achieves good radiation performance, but also exhibits advantages such as low profile, easy fabrication, and low cost.

Single-Layer Dual-Band Reflectarray Antennas With Wide Frequency Ratios and High Aperture Efficiencies Using Phoenix Elements

A novel design methodology for single-layer dual-band reflectarray antennas with wide frequency ratios is proposed by exploiting the unique reflection phase properties of Phoenix elements. Full 360° phase ranges at both frequency bands are achieved simultaneously by using only one element set. Compared to conventional approaches that use two sets of elements for dual-band operation, physical and electromagnetic mutual interferences between the elements operating at different frequency bands can be completely avoided. A detailed design procedure for single-layer dual-band reflectarrays with a wide frequency ratio up to 2.5 is presented, and a set of three center-fed dual-band reflectarrays operating at 15/10, 20/10, and 25/10 GHz, respectively, are designed and numerically verified using full-wave simulations. Furthermore, an offset-fed single-layer dual-band reflectarray operating at 20/10 GHz with a circular aperture of 400 mm in diameter is designed, fabricated, and tested for experimental verification. The measured gains are 36.1 dBi with an aperture efficiency of 58.0% at 20 GHz and 30.3 dBi with an aperture efficiency of 61.1% at 10 GHz, respectively. The measured 1-dB gain bandwidth is 9.1% and 14.0% at the upper and lower bands, respectively. Both the simulated and measured results successfully demonstrate the effectiveness of the proposed design methodology.

A Low-Cost Metal-Only Reflectarray Using Modified Slot-Type Phoenix Element With 360° Phase Coverage

A novel slot-type phoenix element is proposed for low-cost metal-only reflectarray designs. Due to its unique rebirth capability, a full 360° phase coverage is obtained by the proposed phasing element, which can effectively resolve the phase range limitation commonly seen in slot-type metal-only reflectarray elements. A Ku-band offset-fed reflectarray prototype with a circular aperture of 516 mm in diameter is designed, fabricated, and tested for verification. The measured gain is 33.9 dBi at 12.5 GHz with the aperture efficiency of 53.8%, and the 1-dB gain bandwidth is 12.8%. The proposed metal-only reflectarray achieves good radiation performance and is suitable for high-gain antenna applications with stringent requirements on cost and/or working environment.

Design of a dual-frequency broadband reflectarray using triple-resonance elements

A dual-frequency, broadband reflectarray antenna with dual linear polarizations using triple-resonance elements is presented. The phasing element consisting of double square loops and an inner square patch is optimized to simultaneously provide desired phase shifts at the receiving and transmitting frequencies at Ku band. A reflectarray with a square aperture size of 350 mm × 350 mm is designed and analyzed using full-wave simulation software. The simulated results demonstrate that the gains are 30.85 dB at 12.5 GHz and 31.95 dB at 14.25 GHz, respectively, and the aperture efficiency greater than 45% can be achieved within a broad frequency band of 11.9-15.2 GHz.

A Single-Layer High-Efficiency Wideband Reflectarray Using Hybrid Design Approach

A Ku-band single-layer reflectarray (RA) antenna with high aperture efficiency in a wide frequency band is proposed. The reflectarray element is composed of double square loops and an inner square patch, which operates at two different phasing modes by properly adjusting its geometrical parameters. A hybrid design approach, which combines four commonly used wideband RA design approaches—namely, the subwavelength spacing, multiresonance structures on an electrically thick layer, multitype elements, and the dual-frequency phase synthesis—is adopted to achieve the high-efficiency wideband performance. An offset RA prototype with a 400-mm circular aperture is designed, fabricated, and tested. The measured aperture efficiency is over 60% within the frequency band of interest (12.0–14.9 GHz, 21.6%), and the bandwidth of aperture efficiency over 40% is 29.0%. Well-defined measured radiation patterns within the frequency band of 11.5–15.5 GHz are also obtained, which further validate the excellent radiation performance of the proposed RA design.

An FSS-Backed 20/30-GHz Dual-Band Circularly Polarized Reflectarray With Suppressed Mutual Coupling and Enhanced Performance

A high-efficiency wideband frequency selective surface (FSS)-backed 20/30-GHz dual-band circularly polarized reflectarray antenna is presented. In order to effectively suppress the mutual coupling between the different element sets and improve the aperture efficiency, the variable element size and the element rotation angle phasing techniques are utilized in the multilayer reflectarray element designs at the Ka receive and transmit bands, respectively. Furthermore, a double-layer FSS with double concentric square loops is employed between the 20- and 30-GHz element layers. Thus, the uncoupled 20/30-GHz phase responses can significantly reduce the phase errors and simplify the dual-band reflectarray design process. To experimentally validate the performance of the proposed FSS-backed element configuration, an offset-fed 20/30-GHz dual-band circularly polarized reflectarray with a circular aperture of 400 mm is designed, fabricated, and measured. The measured gains are 36.7 dBic with aperture efficiency of 64.1% at 20.4 GHz and 40.2 dBic with aperture efficiency of 65.4% at 30.2 GHz, respectively. The measured aperture efficiencies exceed 47% within the whole receiving band (19.6–21.2 GHz) and 59% within the whole transmitting band (29.4–31 GHz), respectively. The proposed dual-band circularly polarized reflectarray antenna can be used for satellite communication applications at Ka-band.

Terahertz reflectarray antennas: An overview of the state-of-the-art technology

A reflectarray antenna combines the advantages of reflectors and phased-arrays. Due to its low profile, low loss, and versatile radiation properties, it has emerged as a new generation of high-gain antennas. Meanwhile, terahertz (THz) technology, which locates between microwave and infrared, is a frontier of the state-of-the-art electromagnetic research. Recently, the concept of reflectarray has been extended from microwave to THz and higher frequencies. In this paper, several available design methodologies on THz reflectarray antennas are reviewed, such as printed reflectarray antenna using traditional square patch, dielectric THz reflectarray antenna, and reflectarray antenna using graphene. Moreover, the concept and design methods about infrared reflectarray and optical reflectarray are also reviewed. It is expected that this overview will help to stimulate and promote creative THz reflectarray research in the near future.

Design of a single-layer dual-band metal-only reflectarray

A single-layer dual-band metal-only reflectarray antenna (MORA) is designed for the first time. It is capable to achieve differently-oriented pencil beams with the same linear polarization at X and Ku bands. The slot-type Phoenix elements are used with multi-parameter sweeping strategy to simultaneously provide sufficient phase shift coverage at the two design frequencies. At the reflectarray system design level, the dual-frequency phase-only synthesis method is adopted to further simultaneously minimize phase errors at two designed frequencies. To validate the proposed design, a center-fed MORA with a circular aperture of 400 mm in diameter is designed and simulated. The simulated gains are 29.1 dBi at 10 GHz with aperture efficiency of 46.3%, and 32.5 dBi at 15 GHz with aperture efficiency of 45.1%, respectively.

Design of a Low-Cost Single-Layer X/Ku Dual-Band Metal-Only Reflectarray Antenna

A low-cost single-layer dual-band metal-only reflectarray antenna (MORA) is designed, fabricated, and tested. It is capable of generating pencil beams with the same single linear polarization at X-and Ku-bands. The slot-type Phoenix elements are used to achieve the desired metal-only design, and by using a multiparameter sweeping strategy, they can provide sufficient phase shift coverage at the two design frequencies simultaneously. For the reflectarray system design, the dual-frequency phase-only synthesis method is adopted to further minimize phase errors at both frequencies. To experimentally validate the proposed design, an offset single-layer dual-band MORA prototype with a circular aperture of 380 mm in diameter is designed, fabricated, and tested. The measured gains are 29.1 dBi at 10 GHz with aperture efficiency of 51.3%, and 32.6 dBi at 15 GHz with aperture efficiency of 51.1%, respectively. The measured 1-dB gain bandwidth is 11.5% at the lower band and 17.5% at the upper band, respectively.

Design of a Ku/Ka quad-band reflectarray antenna for satellite communications

A quad-band reflectarray antenna that operates at both Ku (12.5 and 14.25 GHz) and Ka (20.4 and 30.2 GHz) bands is designed for satellite communications. The multi-layer configuration is adopted with the frequency selective surface (FSS) backed Ka-band elements above the Ku-band elements. An FSS with triple ring slots is optimized to achieve transmission at Ku band and reflection at Ka band simultaneously. A triple-resonance element with two square loops and a square patch is designed for wideband operation at Ku band, while a Phoenix-type element is designed for dual-frequency operation at Ka band. The dual-frequency phase synthesis method is then utilized separately at both bands to achieve receive/transmit coverage. The full-wave simulation of the proposed reflectarray using CST with GPU acceleration verifies that good radiation performance is successfully obtained with aperture efficiencies of 46.0%, 47.6%, 68.6%, and 55.7% at four operation frequencies, respectively.