Broadband Reflectarray Antenna on a Periodically Perforated Substrate (original) (raw)
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Reflectarray Antenna with Radar Cross-Section Reduction
penerbit.uthm.edu.my
This paper presents the design of a low RCS reflectarray at 8.52 GHz by replacing the solid metal sheet behind the antenna with a band stop frequency selective surface. A 50 element linear array of omni-directional elements was used to simulate the far field pattern of a reflectarray with f/D=0.325 in the plane of the elements to assess the effect of an imperfect aperture distribution on the gain and sidelobe levels. It is found that the reflection loss variation across the aperture does not have a significant effect on the radiation pattern of the antenna, because for the layout that was studied, only a few of resonant loops were predicted to give a significantly different loss than the others in the array. Simulated and measured results show that the 'in-band' reflection phase response of the structure with metal ground plane and with a periodic FSS ground plane is very similar, however the periodic ground plane reduces the 'out of band' reflectivity by more than 4 dB, thereby decreasing its RCS profile to these signals.
Design and performance of a microstrip reflectarray on a uniaxial substrate
Canadian Journal of Physics, 2002
A design formulation of microstrip reflectarrays is presented in this paper. Previous published articles, referring to this subject, present results for reflectarrays on a uniform dielectric substrate. In this work microstrip reflectarrays with offset feed, dual polarization, and side-lobe level under control, fabricated on a uniaxial substrate were studied. The method of moments, combined with the full-wave technique, and the corresponding dyadic Green's function is used for the specification of the electromagnetic field scattered by the array. PACS No.: 84.40B
Wideband perforated rectangular dielectric resonator antenna reflectarray
2011 IEEE International Symposium on Antennas and Propagation (APSURSI), 2011
A wideband perforated rectangular dielectric resonator antenna (RDRA) reflectarray is presented. The array of RDRA are formed from one piece of material. Air-filled holes are drilled into the material around the RDRA. This technique of fabricating RDRA reflectarray using perforations eliminates the need to position and bond individual elements in the reflectarray and makes the fabrication of the RDRA reflectarray feasible. The ground plane below the reflectarray elements is folded to form a central rectangular concave dip so that an air-gap is formed between the RDRA elements and the ground plane in order to increase the bandwidth. Full-wave analysis using the finite integration technique is applied. Three cases are studied. In the first one, the horn antenna is placed at the focal point to illuminate the reflectarray and the main beam is in the broadside direction. In the second one, the horn antenna is placed at the focal point and the main beam is at ±30 degrees off broadside direction. In the third one, an offset feed RDRA reflectarray is considered. A variable length RDRA provides the required phase shift at each cell on the reflectarray surface. The normalized gain patterns, the frequency bandwidth, and the aperture efficiency for the above cases are calculated.
Perforated Dielectric Resonator Antenna Reflectarray
2011
A wideband perforated rectangular dielectric resonator antenna (RDRA) reflectarray is presented. The array of RDRA are formed from one piece of material. Air-filled holes are drilled into the material around the RDRA. This technique of fabricating RDRA reflectarray using perforations eliminates the need to position and bond individual elements in the reflectarray and makes the fabrication of the RDRA reflectarray feasible. The ground plane below the reflectarray elements is folded to form a central rectangular concave dip so that an air-gap is formed between the RDRA elements and the ground plane in order to increase the bandwidth. Full-wave analysis using the finite integration technique is applied. Three cases are studied. In the first one, the horn antenna is placed at the focal point to illuminate the reflectarray and the main beam is in the broadside direction. In the second one, the horn antenna is placed at the focal point and the main beam is at ±30 degrees off broadside direction. In the third one, an offset feed RDRA reflectarray is considered. A variable length RDRA provides the required phase shift at each cell on the reflectarray surface. The normalized gain patterns, the frequency bandwidth, and the aperture efficiency for the above cases are calculated.
Antennas and Propagation …, 2012
In order to design reflectarray antennas within reasonable CPU times, fast and accurate numerical tools for the analysis of periodic multilayered structures are required. In this paper the method of moments in the spectral domain (MoM-SD) based on multilayered Green's functions (MGF) is applied to the analysis of periodic structures containing multilayered stacked patches in the unit cell. These multiresonant cells are potential elements for the design of reflectarray antennas. In the paper we show that the use of basis functions with edge singularities in the approximation of the current density on the patches leads to important computer memory and CPU time savings in the analysis of the periodic structures. Also, a rational fitting technique is introduced which makes it possible to obtain closed-form expressions for the scattering matrix of the periodic structures in terms of the dimension of the patches used to adjust the phase of the reflectarray elements.
Analysis and Design of Reflectarray Antennas Based on Delay Lines: A Filter Perspective
IEEE Access, 2020
The analysis and design of reflectarray (RA) antennas based in delay lines is introduced for the first time from a filter perspective. To this purpose, each unit-cell of the RA is considered as a network composed of two ports, one being the delay line and the other one the free-space. This approach allows to borrow the coupling matrix formalism from filter theory and apply it to design unit-cells exhibiting broadband operation together with very sharp frequency responses. The concept is demonstrated with the aid of planar printed unit-cells coupled to substrate integrated waveguides (SIWs) through slots, a configuration that offers significant advantages to shape its frequency response while providing relatively low loss. With the aim of validation, a third order filter structure integrated in SIW-based unit-cells has been experimentally tested using the waveguide simulator technique, at a center frequency of 9 GHz. Measurements demonstrate a high-quality linear phase variation and range, and large frequency selectivity together with broadband response for the element of about 18%. The experimental results show the feasibility of this approach for the design of broadband reflectarray antennas exhibiting sharp gain responses. To illustrate the concept, a medium size reflectarray has been theoretically designed using the proposed unit cell at 9 GHz, showing a directive beam with 35.8 dB gain, sharp gain selectivity over 18 dB, and confirms the wide band operation with 20.3% bandwidth for a 3 dB gain variation. INDEX TERMS Broadband antennas, delay-line elements, filter theory, gain selectivity, reflectarray antennas, substrate integrated waveguide.
A Novel Reflectarray Antenna with Reduced RCS
Kocaeli Journal of Science and Engineering, 2018
A novel frequency selective surface (FSS) configuration in the reflectarray antenna is proposed for the reduction of radar cross section (RCS) level in this work. Double-layer FSS structure is located behind the reflectarray antenna as a ground. A 9×9 elements FSS with variable size patches has same geometry with the reflectarray antenna. The RCS reduction performance of reflectarray antenna for both ground plane backed and FSS backed is compared. The results of simulation are obtained by using CST Microwave Studio. The simulation results show that RCS level of FSS backed reflectarray antenna is reduced both in-band (8-12 GHz) and out-of-band (2-7 GHz and 13-18 GHz). In the literature, RCS reduction of reflectarray antenna with FSS structure has only been achieved out-of-band. Furthermore, the gain and radiation performance of the ground plane backed reflectarray antenna and FSS backed reflectarray antenna are compatible with each other.
Implementation of an Innovative Method to Design Reflectarray Antennas
International Journal of Antennas and Propagation, 2012
A novel computed aided technique for designing reflectarray antennas is presented. The developed approach automatically generates the geometrical model of reflectarray antennas taking into account some input parameters, such as, the unit cell type and dimensions, frequency, focal length, periodicity, dielectric materials, and desired main beam radiating direction. The characteristics of the reflecting elements are selected considering the spatial phase delay at each unit cell to achieve a progressive phase shift. The implemented procedure also provides the phase characteristic of the unit element, which is rapidly computed by using a parallelized Moment Method (MoM) approach. The MoM is also used to obtain the radiation pattern of the full reflectarray antenna. In order to evaluate the new technique, a dual-interface prototype has been designed and simulated showing high-performance capability.