High performance resonant cavity antenna with non-uniform metamaterial inspired superstrate

Abstract

The resonant cavity antenna (RCA) is a class of widely used high gain antennas, but usually suffers from narrow impedance bandwidth owing to its strong resonant property, as well as relatively low aperture efficiency because of its non‐uniform electromagnetic (EM) field distribution on the aperture. This article explores enhancing the RCA's impedance bandwidth and aperture efficiency by designing a non‐uniform metamaterial inspired superstrate, on which the metal patches vary their sizes with respect to their distances to the superstrate's center. After optimized by the Genetic Algorithm, the proposed RCA is designed, fabricated and tested. Measured results agree well with simulated ones and show that in comparison with a RCA with a uniform metamaterial inspired superstrate, this work significantly improves the |S11| < −10 dB impedance bandwidth from 2.1% to 6.1%, the gain at the working frequency 10 GHz from 19.07 dBi to 20.55 dBi, and correspondingly the aperture efficiency from 50.5% to 71%. A further analysis estimates that due to the non‐uniform metamaterial inspired superstrate, a more homogeneous distribution for both the amplitude and phase of the EM field is observed on the superstrate's aperture.

Application of metamaterials for performance enhancement of planar antennas: A review

“…In this respect, the emerging notion of metamaterial with different resonator unit shapes has played a great role in reducing the complexity incurred due to the addition of extra structures and improving performance of antennas . In this section, the bandwidth enhancement techniques will be presented by categorizing them based on the placement of metamaterial structure on/near the patch, loaded/etched in the ground plane, embedded in the substrate, and as superstrate …”

“…Simultaneous improvement in bandwidth 240% and 178%, as well as gain 3.92 and 1.98 dBi at the lower and upper bands, were attained using a two‐sided reflective type metasurface deployed above the main radiator. Patch type unit cells of a nonuniform size made the superstrate in Reference for enhancing the impedance bandwidth by 4% and gain by 1.48 dBi for a microstrip patch antenna resonating at 10 GHz. The presence of the superstrate layer made the electromagnetic field to propagate homogeneously in both magnitude and phase at the aperture of the superstrate.…”

Wideband resonate cavity antenna with double‐layer metallic superstrate

“…The electromagnetic wave radiated from the feed antenna has multiple reflections between the superstrate and the metal ground; thus, a cophasal aperture field distribution over the antenna's aperture is realized, thereby achieving a high directivity. 3 Superstrate of the RCAs commonly includes the print circuit boards (PCBs) [6][7][8][9][10][11][12][13] and metallic layers. [14][15][16][17][18][19][20][21][22][23][24] Due to the advantage of easy fabrication, most RCAs are combined with PCB superstrate.…”

Compact ultrathin linear graded index metasurface lens for beam steering and gain enhancement

“…Beam tilting of antenna is achieved by using MS at various frequencies with complicated dimensions in References . The modulated MS with complex dimensions is used in References to improve the radiation pattern of antenna. Frequency and beam scanning transmissive gradient phase MS is presented for antenna applications in References .…”

“…In References , to achieve high gain enhancement in broadside direction MS lenses are used in the far field of primary radiator. A high gain resonant antenna by using nonuniform metamaterial superstrate with gain enhancement of about 1.5 dB is achieved in Reference . A spoof surface plasmon polarization antenna is presented in Reference to achieve high gain with steered frequency scanning.…”