High‐isolated broadband eight‐element linear multi‐input multi‐output array over artificial magnetic surface for wireless and sub‐6 GHz 5G communications

Abstract

Summary A low‐profile eight‐element printed dipole antenna (PDA) array backed by broadband rhomboid artificial magnetic conductor (AMC) is introduced for wireless communication systems. By loading a 4 × 27 AMC reflector into the eight‐element array of PDA, a low‐profile wideband structure with enhanced radiation properties is achieved. The measured S parameters show the broad bandwidth from 4.75 to 7.05 GHz in C‐band with enhanced gains of eight elements (more than 8 dBi) and the suitable isolation between the array elements of more than 23 dB for multi‐input multi‐output (MIMO) systems. The suggested PDA with a pair of the microstrip meandered folded poles excited by an E‐shaped microstrip feedline expands the bandwidth in the range of 5.85–6.95 GHz (S11 ≤ −10 dB). The novel AMC unit cell is realized based on the recognized method as rhomboid coupled parasitic patches. The rhomboid AMC design operates at 6.26 GHz with an AMC bandwidth of 5.20–7.24 GHz (32.8%). Then, the suggested rhomboid AMC surface as a reflector of the antenna is inserted into the PDA to exhibit −10 dB measured impedance bandwidth from 4.94 to 6.93 GHz (more than 33%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 34%, enhanced gain up to 8 dBi, and excellent impedance matching (at least −20 dB) with directional radiation patterns.

AMC-Loaded Low-Profile Broadband Printed 2×2 Array With Gain and Isolation Enhancement Using Equivalent Circuit Model for Wireless Systems

“…Also, a presented array with EBG in [9] operates in 8-9.25 GHz (14.5%) with 96×96×1.6 mm 3 and a gain of 7 dBi. In comparison with the reported works of [29], [30], and [39], the present study shows a new design of printed T-shaped dipoles and planar AMC for lower frequencies of C-band which can extensively be used for wideband vehicular communications and 5G vehicular base stations. The S-parameters of the 2×2 array with the AMC are illustrated in Fig.…”

“…It indicates the considerable outputs including significantly reduced size, extended bandwidth, and improved gain. In this regard, the design with respect to the other reports such as [13], [8], [9], [24], [28]- [30], and [32]- [39] demonstrates a larger bandwidth of 60% and an improved gain of 8.4 dBi with good impedance matching until -50 dB. For example, a suggested array in [24] with the size of 75×75×12.7 mm 3 covers a wide frequency band of 3-4.1 GHz and a high gain of 7.1 dBi.…”

“…It should be noted that broadband microwave devices and printed antennas with AMCs suffer from a narrow AMC bandwidth [24]. Recently, low-profile microstrip antennas with broadband AMC surfaces are utilized with improved properties by developing a variety of printed circuit technologies [25]- [39]. A reported antenna with AMC introduces a measured bandwidth of 2.2-2.72 GHz (18%) with 67.5×67.5×4.5 mm 3 and a high gain of 5 dBi [34].…”