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Metasurface-based circularly polarized (CP) patch antenna with broadband property is proposed and analyzed in this paper. L-shaped slot coupling method is adopted to feed a 4 × 4 equally divided patch antenna (EDPA). By optimizing the geometry of the feeding structure, broad CP bandwidth is achieved which is much wider than the patch-truncated type. One prototype is fabricated for verification and the results show that the proposed antenna has a wide impedance bandwidth, which is 55.4% ranging from 4.66 to 8.23 GHz (S11 < −10 dB). The 3-dB AR bandwidth is 23.6% from 5.6 to 7.1 GHz, among which a good right-handed circularly polarized radiation is obtained. Furthermore, the gain variation is small (7.3–8.1 dBic). [ABSTRACT FROM AUTHOR]

A substrate-integrated waveguide (SIW) cavity-backed annular ring slot antenna with multiband multimode characteristics is proposed in this communication. The antenna consists of an SIW cavity and an annular slot on top surface as the radiator. Two patch-like radiation patterns and one monopolar radiation pattern at three different frequencies are excited by the single fed antenna. Moreover, each operating frequency can be individually adjusted. A prototype is fabricated and measured to validate the theoretical analysis. Good agreement between the simulated and measured results of the input reflection coefficients and radiation patterns is achieved. Compared with other designs, the proposed antenna has features of simple structure, multiband multimode and frequency-tunable characteristics. [ABSTRACT FROM PUBLISHER]

ABSTRACT A novel ultrawideband antenna with triple band rejection characteristic is proposed in this article. The antenna consists of a U-shaped monopole antenna and a modified grounded plane. To realize triple band-notched characteristics, a pair of I-shaped and L-shaped stubs embedded in the square slots of the ground plane and resonant open-circuited stubs placed adjacent to the antenna edges are used. Surface current distributions are described to analyze the effects of these stubs. Modified version of the antenna is also designed to reduce the overall metallic surface of the antenna while maintaining its band-notched characteristics. Measured results show that this antenna operates from 2.77 to 11.38 GHz for voltage standing wave ratio less than 2, except the triple notched bands (3.27-3.75, 5.51-5.96, and 6.95-7.65 GHz). © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:822-827, 2014 [ABSTRACT FROM AUTHOR]

A $16 \times 16$ substrate-integrated waveguide (SIW) cavity-backed array antenna is proposed in this paper. The array consists of two layers. The top layer employs novel SIW-based subarrays with a compact size. The bottom layer is an 8 \times 8$ SIW corporate-feed network to feed the subarrays. The Chebyshev amplitude weighting is employed in the feed network, which substantially reduces the side lobe level (SLL). The array antenna is fabricated using low-cost printed circuit board technology. The experimental results show that the proposed array antenna has a large bandwidth of 15% from 18.5 to 21.5 GHz with a peak gain of 29.1 dBi at 20.5 GHz. Across the entire band, high radiation efficiency above 62% and a low SLL below - 17\,\mathbf{dB} are realized. The design principle can be used as a guidance for large-scale planar array antenna design and the proposed antenna can be used as a receiving antenna located on the ground in satellite communication systems. [ABSTRACT FROM PUBLISHER]

ABSTRACT A broadband circularly polarized patch antenna with suspended structure is proposed. The suspended patch has a bow-tie structure and a gap-coupled feed. By connecting a resistor load to another gap-coupled feed port at the opposite position, a wide impedance and axial ratio (AR) bandwidths are obtained. The proposed design has a very simple antenna structure with an impedance bandwidth of 44.5% and a 3-dB AR bandwidth of 33.8%, respectively. The results show that the bandwidth of the patch antenna is successfully broadened using the suspended configuration, gap-coupled feed, and resistor loading. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:587-593, 2014. [ABSTRACT FROM AUTHOR]