Fence Shaping of Substrate Integrated Fan-Beam Electric Dipole for High-Band 5G

1. Introduction

3,4,

In wireless communication transceivers, high performance integrated antenna design is very critical for achieving a good signal-to-noise ratio performance [ 1 ]. Recently, antenna design for high-band 5G wireless has greatly attracted the attention of the research community in both industry and academia, owing to the promises of 5G to overcome the limited bandwidth and data rates of the 4G standard, together with the ability to support the expected mobile traffic explosion by 2020 [ 2 5 ].

El) greater than 100° [

Designing mmWave antennas is challenging, especially on the mobile device side, which is the target of this work. The free space path loss that accompanies mmWave communications is much higher than that with the current sub-6 GHz mobile standards, owing to the high frequency propagation [ 6 ]. This dictates the need for directional high gain antennas. In addition, for better coverage, a wide fan beam is required [ 7 ]. Moreover, the antenna needs to be implemented at the mobile device edge [ 8 ]. For area-limited mobile devices, implementing the array at the device’s edge can result in an area-efficient full 3D space coverage, as opposed to planar structures [ 9 10 ] offering only sub-hemispherical coverage [ 11 ]. To summarize, for the mobile device mmWave edge antenna to be able to achieve good performance, it requires a gain higher than 10 dBi, a fan beam with HPBW in the elevation plane (HPBW) greater than 100° [ 8 ], together with compact size and high front-to-back radiation ratio (F/B) to avoid interaction with the RF transceiver circuits. Achieving all those requirements at the same time is challenging. The focus of this work was to develop and design an antenna that is capable of meeting all of those specifications simultaneously.

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A couple of interesting edge-implemented antenna designs exist in the literature [ 12 15 ]. However, they suffer from some limitations. In Reference [ 12 13 ], a 28 GHz mesh grid array was presented. They employed a large number of array elements, which requires a large number of phase shifters for beamsteering, which in turn complicates the design of the phase shifter RF chip and results in higher power consumption. In Reference [ 14 ], a Ka-band dipole array loaded horn antenna was introduced, which suffered low F/B and HPBW. A beamsteering phased array, implemented as 16 cavity-backed slot antennas, proposed in Reference [ 15 ] to operate in the 28 GHz band, suffered from degraded low F/B and HPBW. Hence, it can be concluded that the aforementioned structures are not able to achieve the high gain, HPBW, and F/B requirements simultaneously.

El). In fact, the fence did more than just suppressing the back radiation. Modulating the geometric shape of the fence helped control and improve the dipole’s radiation performance. This is a property of the electric dipole which magneto-electric dipoles [

In Reference [ 16 ], the authors proposed a mm-Wave electric dipole surrounded by a rectangular fence to suppress back radiation that simultaneously achieved high gain, F/B, and HPBW in the elevation plane (HPBW). In fact, the fence did more than just suppressing the back radiation. Modulating the geometric shape of the fence helped control and improve the dipole’s radiation performance. This is a property of the electric dipole which magneto-electric dipoles [ 17 18 ] cannot offer. Fence shaping adds more degrees of freedom, and gives more flexibility to the electric dipole design to satisfy different scenarios. In this work, the fence shaping capability of the electric dipole was studied and analyzed where different fence shapes (shown in Figure 1 ) were examined, namely, V-shaped and U-shaped fences, in addition to the conventional rectangular fence. The proposed structure features stable radiation pattern over a wide frequency range from 24 GHz to 32 GHz allowing it to support multiple 5G bands, more specifically, the 24 GHz, the 26 GHz, the 28 GHz and the 32 GHz frequency bands [ 19 20 ].

The rest of the paper is organized as follows; the conventional dipole antenna with rectangular fence is summarized in Section 2.1 . The effect of fence shaping is introduced in Section 2.2 , and the performance comparison between the different fences is presented in Section 2.3 . Finally, the fabricated prototypes, measurement results, and comparison with the state-of-the-art structures are presented in Section 3