In this paper, a compact dual-polarized ultra-wideband dipole antenna is realized by exciting three resonant modes using double-loop (DL) dipoles with stepped exponential-shaped (ES) arms. First, a single-loop (SL) crossed dipole antenna using the modified direct feeding (MDF) structure with ES arms is designed and analyzed to achieve wide bandwidth (1.7-2.7 GHz) with two resonant modes. Second, without increasing the volume of the antenna, one more loop is employed to gain one more resonant mode to enhance the bandwidth into 1.68-3.7 GHz and fractional bandwidth (FBW) up to 75% for VSWR < 1.5. In order to adjust three resonant modes independently, the ES arms of the DL dipole antenna are designed in stepped shapes. The HPBW is 65-70 • for 1.7-2.7 GHz (2G/3G/4G) and 95 • for 3.4-3.6 GHz (5G). In addition, the proposed antenna can also be designed with a bandwidth of 2.38-6.42 GHz (FBW of 92%) for VSWR < 2, occupying WLAN/4G/5G. As demonstrations, the proposed antennas covering 1.68-3.7 GHz for VSWR < 1.5 (Antenna A) and 2.38-6.42 GHz for VSWR < 2 (Antenna B) are designed, fabricated and measured, and the measured results agree well with the simulations.INDEX TERMS Three resonant modes, ultra-wideband, dual-polarized, compact, crossed dipole antenna.
In this paper, a dual-band dual-polarized crossed dipole antenna with good anti-interference capability is proposed for 2.4-/5-GHz WLAN applications. The proposed antenna covers the WLAN 2.4-GHz band (2.4-2.48 GHz) and 5-GHz bands (5.15-5.85 GHz) with isolation >27 dB for VSWR < 2. Without extra filtering circuit, a band-notch (3.4-3.6 GHz) is achieved by introducing the C-shaped split ring resonator (SRR) into the wideband dipole antenna. Compared with the original wideband dipole antenna, the minimum gain in the notched band is suppressed from 8 to −9 dBi and the gain in the higher band is improved from 6 to 9.7 dBi. The proposed antenna can realize a high gain of 7.85 dBi for the lower band and 9.7 dBi for the higher band. As demonstrations, two reference antennas and the proposed antennas are fabricated and measured, and the measured results agree well with the simulated ones. INDEX TERMS Dual-band, dual-polarized, filtering antenna, band-notch, split ring resonator, high gain.
A multi-beam cylindrical Luneberg lens antenna loaded with multiple light dielectric posts for the purpose of light weight is presented. The antenna is based on a parallel-plate waveguide and specifically composed of 10 E-shaped patch antennas feeds, 2 parallel plates, and 491 epoxy posts. The equivalent gradient index of the Luneberg lens antenna is realized via the positions of the epoxy posts between the parallel plates. The features of low-profile height (0.55λ) and large radiating area (4.4 × 0.55λ 2 ) of the cylindrical Luneberg lens result in wide beamwidth in elevation plane and high gain while operating at 4 GHz. Consequently, the 3 dB beamwidth in the elevation plane is >65 . Furthermore, the multi-beams cover a wide scan angle of 120 in the azimuth plane. The measured aperture efficiency of the fabricated lens antenna is above 50% from 3.9 to 4.3 GHz. In addition to the good radiation performance, features of light weight and ease of fabrication have also been demonstrated for the proposed lens antenna. K E Y W O R D S cylindrical Luneberg lens, epoxy posts, light weight, multi-beam
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.