Four-Port Wideband Annular-Ring Patch Antenna Generating Four Decoupled Waves for 5G Multi-Input–Multi-Output Access Points

Four-Port Wide-Band Cavity-Backed Antenna With Isolating X-Shaped Block for Sub-6 GHz 5G Indoor Base Stations

“…To sum up, Table 4 compares the features of the most relevant recent publications of indoor base station antennas and the proposed design, highlighting the impedance bandwidth, the size, the isolation, the number of independent ports and the total efficiency. As observed, the proposed design shows wider bandwidth than the one proposed in [8], which is an early access article from IEEE Transactions on Antennas and Propagation, obtaining similar features with a comparable size.…”

“…A compact dualbroadband (0.8-0.9 GHz, 1.7-2.7 GHz) MIMO antenna composed by a microstrip patch with slots and two monopoles for 2G/3G/4G/5G systems is presented in [7]. In addition, a fourport wide-band annular-ring patch antenna has recently been proposed in [8], working at 3.3-5 GHz band. In a previous work, the authors of this paper presented a MIMO antenna with 4 independent ports, but with a low isolation between them [9].…”

“…With this information, a proper isolating element (isolating block) is introduced to fade the non-desired modes. As a result of the inclusion of an isolating block, the coupling between ports is reduced to the minimum required for base station indoor applications, obtaining a four-port decoupled design which improves the performance of some antennas proposed in recent publications like [8]. Unlike the referenced designs based on characteristic modes which try to excite a single mode per independent port, either using direct feeding or differential feeding, in the proposed design each independent port excites a cluster of modes, which provides the wideband behaviour of the antenna.…”

Wideband Four-Port Single-Patch Antenna Based on the Quasi-TM1/2,1/2 Mode for 5G MIMO Access-Point Application

“…For fifth-generation (5G) 4 x 4 multi-input-multi-output (MIMO) operation, both the terminal device and access point require multiple antennas to be embedded therein. For this purpose, compact four-antenna elements capable of generating four isolated waves are attractive for the terminaldevice and access-point applications [1]- [7]. For the terminal device, the four-antenna elements backed by a ground plane and having a low-profile structure of about 1 mm to be especially suitable for application in the back cover of the terminal device have been reported [2]- [4], which leads to compact integration of the MIMO antenna and the terminal device.…”

“…The outer dimensions of the multimode square patch are 0.85λ x 0.85λ at the center frequency. Recently, a four-port annular-ring patch antenna generating four isolated waves in 3.3-5.0 GHz (bandwidth 41% centered at 4.15 GHz) for the MIMO access-point application has also been shown [7]. The annular-ring patch has an outer diameter of 56 mm, about 0.77λ at 4.15 GHz.…”