SLM Printed Wideband Circularly Polarized Multilayer Antenna Array With Reduced Impact by the Manufacturing Imperfection

Abstract

A novel three-dimensional (3-D)-printed wideband circularly-polarized (CP) waveguide based 4 × 4 slotted antenna array is proposed for wireless communications in the paper. For radiating CP waves, several additional eigenmodes are introduced by designing several additional layers. By adjusting the multiple resonances within the cavity, the axial ratio (AR) bandwidth can be enhanced, and the impedance matching can be improved. Due to the good AR performance of the well-designed radiation subarray, the antenna scale can be easily extended by a simple full-corporate-feed network. The multilayered antenna array is fabricated using the cost-effective commercial direct metal laser sintering (DMLS) technology. By incorporating the Huray model, this study considers and simulates the influence of roughness. The antenna has a measured impedance bandwidth of 20.4% (18-22.1 GHz), which is exactly the same as its AR bandwidth. A maximum gain of 21.6 dBic is achieved at 21.3 GHz. It has validated that, compared with state-of-art technologies, the proposed antenna has wide bandwidth and good radiation pattern. The developed antenna shows competitive performance in terms of gain and efficiency with the state-of-the-art antennas. This demonstrates the viability of employing the advanced 3-D printing technique for realizing complex microwave structures, which holds high potential for future wireless communication applications. INDEX TERMS 3-D printing, antenna array, circularly-polarized, wideband, suface roughness.I. INTRODUCTION In order to satisfy the requirements of transmitting data at high speed in common and emerging wireless applications, such as satellite communications and the internet of things (IoT) [1]-[4], antennas are in increasing demand to have high-gain, wideband, and high efficiency. Furthermore, in wireless communication systems, circularly-polarized (CP) antennas are attracting increasing attention because, as compared to the linearly polarization antennas, CP antennas have obvious advantage of reducing polarization mismatch and multi-path interference [5], [6]. Due to the characteristics of being lightweight, compact, low-cost, and easy to be integrated, microstrip line [7]-[9] and substrateintegrated-waveguide (SIW) based [10], [11] CP antennas are extensively designed for low frequency communication systems. However, these dielectric substrate based antennas are not recommended for high-frequency systems, as the large dielectric loss usually results in obviously limited radiation efficiency [7], [11]. Thus, it is usually difficult to transmit high power with high efficiency by using the