A metasurface-based slit-loaded wideband circularly polarized crossed dipole antenna

Abstract

A metasurface-based low-profile crossed dipole antenna with wide circularly polarized bandwidth for 2.45 GHz ISM band wireless communications is proposed and fabricated in this article. Consisting of four slit-loaded rectangular patches, the double-sided printing crossed dipoles are fed by a pair of vacant-quarter printed rings which circularly polarized (CP) radiation could be generated. With slits loaded, by properly combining the fundamental mode of the two inverted L-shaped dipole, the slot mode and extra resonance generated by the AMC surface, a wideband circularly polarized operation can be obtained. After optimization, the final design with an overall size of 0.44k 0 3 0.44k 0 3 0.1448k 0 at 2.4 GHz had measured a 31.6% (2-2.75 GHz) impedance bandwidth and 3 dB axial ratio bandwidths of measured were 23.2% (2.1-2.65 GHz), respectively. In addition, the antenna performed a small gain variation (7.0-7.5 dBic) and a front-to-back ratio (FBR) of over 25 dB across the whole CP region. K E Y W O R D SAMC, circularly polarized, low profile, wideband | I NT ROD UCTI ONNowadays, in the fields of electronic countermeasure and communication, circular polarized technique has been widely used. When two degenerate modes of equal amplitude and phase difference of 908 were excited, a circular polarization (CP) could be achieved. 1 To achieve CP radiation, several printed monopoles have been proposed.2-11 LP and CP operations were achieved by a multiband coplanar monopole antenna with the trapezoidal structure adopted in ref. Recently, with intensely studied in metamaterials (MTMs), the performance of the traditional CP patch antenna has been improved by utilized MTMs. Improvements of enhancements in bandwidth and an overall reduction in size were included. For an overall size of 0.77k 0 3 0.77k 0 3 0.06k 0 , a 3 dB AR bandwidth of 15% was achieved by a diagonal slot-loaded square patch over a 458-oriented reactive impedance surface (RIS).14 An artificial ground structure was applied in a truncated corner square patch in ref. 15, where an AR bandwidth of 20.4% and an overall size of 0.78 k 0 3 0.80 k 0 3 0.096 k 0 has been achieved. To achieve an overall size of <0.3 k 0 3 0.3 k 0 3 0.03 k 0 , MTMs-based single-feed CP patch antennas [16][17][18][19] have been implemented, but narrow 3-dB AR bandwidths (only 5% or less) were exhibited. In refs. 16,20,21, it proposed an AMC and has since been widely applied. Then, a wide CP operation were obtained, but significantly radiation performances and enhancing the bandwidth of and the size of an antenna could be both reduced by applying such surfaces.Int J RF Microw Comput Aided Eng. 2018;28:e21173.

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Novel wide-beam cross-dipole CP antenna for GNSS applications

“…To achieve multiple resonances, each dipole arm is divided into four branches with different lengths, and a printed inductor with a barbed end is inserted in each branch to reduce the radiator size . With slits loaded, properly combining the fundamental mode of the two inverted L‐shaped dipole, the slot mode and extra resonance generated by the artificial magnetic conductor (AMC) surface, a wide band circularly polarized operation can be obtained …”

A printed dual‐band dipole filtenna with flexible frequency ratio and improved band‐notched performance

“…In the past, extensive research on dipole antennas has been made for dual/ multiband operations . Printed dipole antennas with two L‐slotted or U‐slotted arms for dual‐band operation are proposed in Refs 3 and 4.…”

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