Wideband Omnidirectional Slotted-Waveguide Antenna Array Based on Trapezoidal Slots

Abstract

This manuscript presents a novel approach for designing wideband omnidirectional slotted-waveguide antenna arrays, which is based on trapezoidal-shaped slots with two different electrical lengths, as well as a twisted distribution of slot groups along the array longitudinal axis. The trapezoidal section is formed by gradually increasing the slot length between the waveguide interior and exterior surfaces. In this way, a smoother impedance transition between waveguide and air is provided in order to enhance the array operating bandwidth. In addition, we propose a twisting technique, responsible to improve the omnidirectional pattern, by means of reducing the gain ripple in the azimuth plane. Experimental results demonstrate 1.09 GHz bandwidth centered at 24 GHz (4.54% fractional bandwidth), gain up to 14.71 dBi over the operating bandwidth, and only 2.7 dB gain variation in the azimuth plane. The proposed antenna array and its enabling techniques present themselves as promising solutions for mm-wave application, including 5G enhanced mobile broadband (eMBB) communications.

5G NR FR2 Femtocell Coverage Map Using an Omnidirectional Twisted SWAA

“…As a disadvantage, as resonant antennas, they are usually narrowband. In this context, the high-gain omnidirectional twisted SWAA from [18] has been chosen as the radiating element for the indoor 5G NR FR2 coverage map assay. Our antenna array is based on three new techniques proposed by our research group, namely: trapezoidal-shaped slots; the use of groups of slots with distinct electrical lengths for creating multiple resonance frequencies; twisted distribution of slot groups along the array longitudinal axis.…”

“…Such an application could be easily implemented by using a unique antenna with high gain and an omnidirectional radiation pattern. Diverse omnidirectional antenna and antenna arrays have been proposed in literature for both microwave [11][12][13] and mm-waves [14][15][16][17][18]. Particularly for mm-waves, Q. Jia et al [14] have proposed a cylindrical conformal array antenna applied to 5G micro base stations with switched beam capability.…”

“…Particularly for mm-waves, Q. Jia et al [14] have proposed a cylindrical conformal array antenna applied to 5G micro base stations with switched beam capability. Furthermore, our research group has been intensely contributing to the development of slotted waveguide antenna arrays (SWAA) for 5G FR2 systems [15][16][17][18]. For instance, in [17] we have reported a ring-based omnidirectional antenna with 12-dBi gain and 2.15 GHz bandwidth for the 28 GHz band.…”

“…For instance, in [17] we have reported a ring-based omnidirectional antenna with 12-dBi gain and 2.15 GHz bandwidth for the 28 GHz band. In addition, we have introduced a novel wideband and high-gain omnidirectional SWAA [18] based on three efficient techniques, namely: trapezoidal-shaped slots for generating a smooth impedance transition between waveguide and air; groups of slots with different electrical lengths for producing multiple resonances; twisted distribution of slot groups along the array longitudinal axis, by applying an angular displacement.…”

“…Completely, the current manuscript reports the implementation and coverage map estimation of an indoor femtocell based on the new 5G NR standard [4] operating in FR2. Additionally, a novel wideband and high-gain omnidirectional SWAA [18] has been applied to the 5G NR femtocell implementation, aiming to demonstrate its applicability in a real scenario and make feasible an omnidirectional coverage, under line-of-sight (LOS) and NLOS (non-LOS) propagation conditions. In particular, the coverage map estimation is based on the EVMRMS requirements from the 3GPP.…”