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A differentially fed dual-polarization slotted antenna with an ultra-wide bandwidth and low cross polarization is presented in this paper. The antenna is composed of a radiation patch and a ground plane, both of which are printed on the top of the dielectric substrate. The ground is extended toward the radiation patch to form a slotted coplanar structure. In order to expand the bandwidth, a cross-shape symmetrical slotted structure is loaded into the radiation patch. Differential feed is adopted to realize 0°C/90°C linear polarizations and suppress the cross polarization. Simulation and measurement results show that the proposed antenna with dimensions of 0.53λC0 × 0.53λ0 × 0.0135λ0 (λ0 is the wavelength at 4 GHz) has a differential mode impedance bandwidth of 82.25% (2.27-5.56 GHz), a differential feed port isolation of higher than 28 dB, and a cross polarization level of less than -30 dB, which achieves the characteristics of ultra-wideband, high isolation, and low cross polarization level. [ABSTRACT FROM AUTHOR]

This paper presents a wideband, broad beamwidth, dual-polarized antenna for the indoor access points. Its primary radiating elements are two quasi-Yagi antennas, which are arranged orthogonally. The antenna element employs two balanced directors to broaden bandwidth and avoid the structural conflict of the orthogonal installation. A microstrip-slotline transformer is used in the feeding structure for allowing the wideband operation and high port-to-port isolation. The dualpolarized quasi-Yagi antenna is incorporated with a metallic cavity in order to improve the unidirectional radiation in terms of gain, front-to-back ratio, and beamwidth. The final prototype has been fabricated and tested. The antenna yielded a wide impedance bandwidth covering a frequency range from 1.64 to 3.0 GHz (60%) for both ports with port-to-port isolation of a higher than 25 dB. In addition, at both ports, the antenna achieves stable unidirectional radiation with broad beamwidth, high front-to-back ratio, and high radiation efficiency. [ABSTRACT FROM AUTHOR]

This paper presents the design of a high gain broadband quadruple-ridged circular horn antenna for Electromagnetic Compatibility (EMC) testing. The proposed antenna contains a wideband feed structure as a transition between coaxial line and quad-ridged circular waveguide behind the conical horn antenna. The wideband matching between impedances at the apertures of the feed and the horn is achieved with a tapering at the flare section along the horn length, which is obtained after a detailed investigation of various tapering profiles. The antenna is designed to operate in horizontal and vertical polarizations (dual linear polarization) simultaneously in EMC tests. This implementation is found to present a return loss greater than 10 dB, isolation level higher than 28 dB, high-gain (minimum 13.6 dBi) and low-gain variation of 4.5 dBi within the frequency range of 1-6.75 GHz (6.75:1 bandwidth) at both polarizations, which is a desired feature in radiated emission and immunity tests. [ABSTRACT FROM AUTHOR]

A compact four-unit ultra-wideband multipleinput multiple-output (UWB-MIMO) antenna with very high isolation, dual polarization, notched structure, and achieving dual-state operation, along with smaller volume, is proposed in this paper. The proposed MIMO antenna element consists of two parts: the front patch composed of four symmetrical trapezoidal radiating elements and feeder, and the back composed of a rectangular annular ground. The offset of antenna operating frequency band is achieved by adjusting the rectangular patch in the middle of the back side, and by introducing an X-shaped metal narrow strip on the top side and an X-shaped slit on the bottom side to improve the isolation in the single port feeding state of antenna. Finally, the dimension of the antenna is 32 × 32mm2. Under the frequency from 3.1 GHz to 10.6 GHz, the isolation in the condition of differential mode can below -30 dB, which is very high, and also can work in the single port inputting state, showing a dual mode operation. In addition, a trapezoidal slit is introduced to obtain a notch structure. The measured results and simulation results are consistent. [ABSTRACT FROM AUTHOR]

We describe the additive manufacturing results pertaining to a multi-function antenna aperture. The antenna consists of customized high dielectric and low loss feedstocks as the enabling technology. The 3D printed prototype shows agreement with simulation while providing excellent performance. [ABSTRACT FROM AUTHOR]