A High-Selectivity Wideband Millimeter-Wave Magnetoelectric Dipole Filtenna

In this paper, a millimeter-wave (mmW) wideband high-isolation wide-angle scanning antenna is presented. The end-fire magnetoelectric (ME) dipole with wideband impedance characteristic and wide beamwidth is selected. Based on the ME dipole, a 1×4 subarray with a stripline feed network is constructed to get higher antenna efficiency. Then, four 1×4 subarrays are adopted to form a 4×4 array to realize the wide-angle scanning performance. Furthermore, to get better isolation between the subarrays, the beam is tilted on the non-scanning plane; in addition, the resonant split rings are added on the background of the subarrays. With these two measures, the isolation between the subarrays can be effectively reduced, with more than 20 dB over the entire bandwidth. Owing to the wide beamwidth of ME dipole and high isolation between the subarrays, the 4×4 array can obtain the wide-angle scanning characteristic. The final antenna covers an operating bandwidth of 19.5% (24.25-29.5 GHz) with return loss more than 10 dB, which can meet the band in the 5G standard. The beam can scan approximately ±55∘ with a realized gain reduction under 3 dB within the wide operating bandwidth. Also, the simulated radiation efficiency of the array is more than 77% over almost the entire band. The antenna will be a potential candidate to be applied in 5G applications.

A wideband millimeter-wave magneto-electric (ME) dipole antenna with end-fire radiation, which is fed by the substrate integrated coaxial line (SICL), is designed, fabricated, and measured. First, the ME-dipole antenna excited by a planar L-probe is presented to realize wideband performance. Then, a wideband impedance conversion structure is used to connect the antenna and the feeding port. A simple conversion structure for the SICL to the grounded coplanar waveguide is used for the antenna test. Finally, the simulation and measurement results validate the proposed end-fire ME-dipole antenna. The overall bandwidth is greater than 40% considering both impedance bandwidth and 3-dB gain bandwidth.

A wideband endfire magnetoelectric (ME) dipole antenna fed by substrate integrated coaxial line (SICL) is presented. Endfire radiation is achieved by the combination of a horizontally oriented quarter-wave shorted patch and a dipole array loaded at the patch aperture. A direct-feeding mechanism based on the SICL structure is developed to excite the ME-dipole antenna. The proposed feeding method provides a simple yet effective mean of wideband impedance tuning. The antenna exhibits a wide impedance bandwidth of 77%, covering from 23.1 to 52 GHz, and a small lateral size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.32\lambda _{0}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> refers to the wavelength in free space at the center frequency, i.e., 38 GHz). In addition to its wideband performance and compactness, highlights, including a stable gain of around 5.5 dBi, low backward radiation, and low cross polarization, are also achieved. In particular, the proposed design outperforms most state-of-the-art millimeter-wave endfire antennas with a notable bandwidth.

In this paper, we present a new millimeter-wave wideband magneto-electric dipole antenna which consists of four metal patches, four sets of vias and an L-shaped probe. This antenna, operating at 60GHz, achieves a wide impedance bandwidth of over 50%, a maximum gain of 9.5dBi and relative high antenna efficiency. The antenna is made of low-cost printed circuit board. Two kinds of feeding technique for this antenna is investigated.

A millimeter-wave high-gain dual-polarized antenna array with an enhanced bandwidth is presented. An innovative air-filled differential feeding cavity loaded with a short-ended cross-shaped waveguide is investigated to serve as the feed network and the mode splitter simultaneously of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\,\,\times2$ </tex-math></inline-formula> dual-polarized subarrays. Wideband characteristics and a compact planar size that are desirable for the wideband array design are achieved. Moreover, a wideband dual-polarized waveguide-fed magnetoelectric (ME) dipole antenna with a lightweight self-support geometry and wideband H-plane parallel feed networks with modified dual-layered configurations are proposed, which are convenient to connect with the differential feeding cavity directly. With the use of a commercial metallic 3-D printing facility, the proposed radiating elements, feeding cavities, and feed networks can be combined successfully in a whole piece with a lightweight geometry. The printed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8 \times 8$ </tex-math></inline-formula> array prototype operating in the Ka-band confirms a wide bandwidth of about 30%, a gain of up to 28.5 dBi, and stable unidirectional radiation patterns for the two polarizations. Benefitted from the advantages of the promising wideband dual-polarized radiations and convenience of fabrication, the proposed antenna array would be attractive for millimeter-wave polarization diversity applications.

A millimeter-wave wideband dual-polarized 2 × 2 antenna array is investigated based on three-dimensional (3D) printing technology. A novel differential feeding cavity loaded with a short-ended cross-shaped waveguide and four shorting pins is designed to act as mode splitter and power divider for two polarizations. By combining with the modified cavity-backed self-supporting magneto-electric (ME) dipoles, good characteristics including wide bandwidths, stable gains and unidirectional radiation patterns for two polarizations can be obtained. It has been demonstrated that the proposed antenna array is suitable for millimeter-wave polarization diversity applications.

Millimeter-Wave Wideband Dual-Polarized Aperture-Coupled Magnetoelectric Dipole Antenna Array With High Isolation

A Millimeter-Wave Wideband Dual-Polarized Magnetoelectric Dipole Phased Array With Scan Blindness Mitigation

A wideband switched-beam gradient index lens antenna system is proposed for millimeter-wave applications. A modified Luneburg lens with a flat focal plane is designed based on the quasi-conformal transformation optics technique. This lens design facilitates the use of a planar array feed and enables wide-angle beam scanning. The proposed lens feed is a 9×9 magneto-electric dipole array operating over 24-40GHz. The proposed lens antenna features a large scanning coverage of ±58° with peak directivity > 19dBi while maintaining excellent pattern integrity and acceptable beam crossover levels over the band.