Indonesian J our nal of Electrical Engineering and Computer Science V ol. 21, No. 3, March 2021, pp. 1611 1621 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v21i3.pp1611-1621 r 1611 Sectoral dual-polarized MIMO antenna f or 5G-NR band N77 base station M. Muhsin 1 , Afina Lina Nurlaili 2 , A ulia Saharani 3 , Indah Rahmawati Utami 4 1,3,4 Department of T elecommunication Engineering, Institut T eknologi T elk om Surabaya, Indonesia 2 Department of Informatics, Uni v ersitas Pembangunan Nasional ”V eteran” Ja w a T imur , Indonesia Article Inf o Article history: Recei v ed Oct 2, 2020 Re vised Dec 2, 2020 Accepted Dec 23, 2020 K eyw ords: 5G Antena Correlation Coupling MIMO ABSTRA CT Massi v e internet of things (IoT) in 5G has man y adv antages as a future technology . It brings some challenges such as a lot of de vices need massi v e connection. In this case, multiple-input multiple-output (MIMO) systems of fer high performance and ca- pacity of communications. There is a challenge of correlation between antennas in MIMO. This paper proposes three-sectors MIMO base station antenna for 5G-Ne w Radio (5G-NR) band N77 with dual polariz ed configuration to reduce the correlation. The proposed antenna has a maximum coupling of -16.90 dB and correlation belo w 0.01. The obtained bit error rate (BER) performance is v ery close to non-correlated antennas with bandwidth of 1.87 GHz. It means that the proposed antenna has been well designed. This is an open access article under the CC BY -SA license . Corresponding A uthor: M. Muhsin Department of T elecommunication Engineering Institut T eknologi T elk om Surabaya Jalan K etintang 156, Surabaya, Indonesia Email: muhsin@ittelk om-sby .ac.id 1. INTR ODUCTION Internet of things (IoT) is becoming a trend in the follo wing year and future [1-4]. It has been s tarted since the fourth generation of telecommunications (4G). In the ne xt telecommunication generation, IoT is e xpected to gro w more massi v ely . Current IoT will be e v olv ed into massi v e IoT , where there is more massi v e connecti vity in the netw orks. Massi v e IoT in 5G is challenging because it should be able to accommodate a v ery high number of de vices simultaneously . Capacity is main problem of massi v e IoT in 5G. It can be realized by pro vide high number of cell, each can handle a high v olume of traf fic [5, 6]. Massi v e traf fic can be di vided into some cells handling traf fic in its co v erage area. Each base station should use MIMO to pro vide enough capacity with high performance. Multiple-input multiple-output (MIMO) is one of primary k e y for 5G [7-15] as enabler of massi v e IoT . Multiple antennas mak es performance impro v ement where one antenna w orks together with other antennas. In order to g ain the best performance, e v ery antenna should be independent of each other . Independence is needed to pro vide optimum di v ersity . So, lo wering dependenc y is one of the main focus in designing the MIMO antenna. It is because the dependenc y between antennas may decrease channel di v ersity which mak es the system’ s performance w orse. Dependenc y is indicated by antenna’ s correlation [16-19]. Depencenc y is measured by correlation between antennas. Some basic techniques ha v e been proposed, for e xample, dual-cross polarized antenna on [20-23], ground decoupling on [24-27], sectorization on [28]. Dual-cross polarized antenna w orks by arranging the antenna so that the neighboring antenna has dif ferent J ournal homepage: http://ijeecs.iaescor e .com Evaluation Warning : The document was created with Spire.PDF for Python.
1612 r ISSN: 2502-4752 polarization. Ground decoupling w orks by modifying the antenna’ s ground to reduce the antenna’ s interaction in the ground part. Sectorization w orks by arranging antennas ha ving dif ferent focus of radiation pattern. Small cell base station for indoor dense netw orks is e v aluated in [29-31]. Main characteristics of small cell 5G IoT base stations are MIMO and lo w co v erage. This base station usually uses mm-W a v e MIMO to pro vide high data rate and limited co v erage. But, this technique has comple xity disadv antages since mm-W a v e de vices are still uncommon and require additional configuration to w ork together with sub-6 GHz netw orks. This paper proposes lo w-correlation MIMO antenna decoupling on 5G ne w radio (5G-NR) Band N77 using three sectors and dual-polarized configuration. It combines s ectorization and dual-polarized techniques. These tw o techniques are combined to pro vide lo w correlation and di viding the cells. Sectorization is used for space di v ersity on each side and dual-polarized is us ed for polarization di v ersity . The antenna is designed and e v aluated by coupling, correlation, and BER performance. The rest if this paper is or g anized as follo ws. Antenna design is presente d in secti on 2 started from single antenna to three-sectors dual- po l arized antenna. Simulation model is e xplained in section 3 Results are presented and discussed in section 4 and then, the conclusion is presented in section 5. 2. ANTENN A DESIGN Antenna is designed in step by step basis from single antenna to 3-sectors dual-polarized MIMO antenna. Single antenna is used as a basic model. And then this design is e xtended to four -elements MIMO dual-polarized antenna in a plane. This 4-elements antenna is then e xtended to 3-sectors dual-polarized MIMO antenna. 2.1. Single Antenna Circular patch microstrip antenna is selected as a basic model of single antenna. This type is chosen due to its simplicity . Basically , circular patch mictrostrip antennas ha v e unidirectional radiation patterns, which can be suitable for each sector of sectoral antennas. Some dimensional parameters can be set to obtain the best performance of the antenna. This single antenna should be well designed because of its role as a basis for a full MIMO antenna. Rogers R T -5880 is used as antenna’ s material with thickness h = 1 : 6 mm. This material has relati v e permitti vity r = 2 : 2 and superior performance compared to FR-4, which is suitable for ultra wide band (UWB) abo v e 3 GHz [32-34]. Material characteristics of R T -5880 allo ws antenna’ s dimension to lo wer manuf acturing error and high po wer capability . This material then designed to obtain the requirement of a single antenna in T able 1. T able 1. Single antenna specification Material : Rogers R T -5880 Relati v e Permitti vity : 2.2 Substrate’ s Thickness : 1.6 mm Conductor : Copper Conductor’ s Thickness : 35 m Frequenc y Range (5G N77) : 3.3-4.2 GHz Maximum Return Loss : -10 dB Radiation P attern T ype : Unidirectional Basically , the single antenna design is started from a simple circul ar disk microstrip antenna. The antenna has circular shaped disk with radius [35-37]: r = F q 1 + 2 h r F ln F 2 h + 1 : 7726 (1) where F = 8 : 791 10 9 f p r : (2) h is substrate’ s height/depth, f is resonant frequenc y , and r is substrate’ s relati v e permitti vity . The antenna is fed with microstrip line with width formulated in [38]. F ormula in (1) didn’ t count fringing ef fect and other ne glected f actors. It means that the optim ization is needed. Antenna’ s ground has been cut to pro vide wider bandwidth. By cutting the ground at certain section, impedance become wider and antenna’ s main lobe become smaller . Indonesian J Elec Eng & Comp Sci, V ol. 21, No. 3, March 2021 : 1611 1621 Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian J Elec Eng & Comp Sci ISSN: 2502-4752 r 1613 a) b) c) Figure 1. Single antenna: (a) 3D vie w , (b) Front vie w , (c) Back vie w Optimized single antenna is sho wn in Figure 1. Disk radius r is 14 mm, feed’ s width w f is 3 mm, ground plane’ s length g is 10 mm, and single antenna’ s plane s is 50 mm. Figure 2. Return loss of single antenna a) b) c) Figure 3. Radiation pattern of single antenna: (a) 3D, (b) Azimuth, (c) Ele v ation Requirement on T able 1 must been met by the single antenna designed. Obtained port reflec tion coef ficient is sho wn in Figure 2. The antenna w orks between 3.06 GHz and 5.08 GHz with return loss belo w -10 dB [36] and 2.08 GHz bandwidth. It means that frequenc y range or bandwidth requirement has been met. Obtained radiation pattern is sho wn in Figure 3. It has been sho wn that the antenna has unidirectional radiation pattern with 2.921 dBi g ain at 3.7 GHz with -0.01686 dB radiation ef ficienc y . It means that radiation pattern requirement has been met. 2.2. Dual P olarized Antenna Antenna from section 2.1. is the basic for dual polarized antenna design. The single antenna is dupli- cated then arranged with dual polarized configuration as seen in Figure 4. Neighboring antennas ha v e dif ferent orthogonal polarization. Crossing antennas ha v e same polarizat ion with dif ferent direction of feeding. This configuration is made to reduce coupling and correlation between antennas [20-23, 16-18]. Sector al dual-polarized MIMO antenna for 5G-NR band N77 base station (M. Muhsin) Evaluation Warning : The document was created with Spire.PDF for Python.
1614 r ISSN: 2502-4752 Figure 4. Dual polarized antenna 2.3. Thr ee Sectors Antenna Dual polarized antenna in section 2.2. then e xtended into three-sectors MIMO antenna. Each sector is composed from one dual-polarized antenna with sector radius r c = 50 mm. Each sector serv es users or subscribers in respecti v e sectors. Three sectors are made based on con v entional sectoral antennas for mobile communications (Figure 5). a) b) Figure 5. 3 Sectors antenna: (a) 3D vie w , (b) Upper vie w 3. SIMULA TION MODEL In this section, a simulation model of the system using designed antennas is e xplained. Simulation is used to demonstrate MIMO antenna’ s performance in the communication systems. The simulat ion in v olv es correlation between antennas as one of i n put parameters. Result of the simulation is BER performance com- pared to ideal non-correlated MIMO antennas. Quasi-Orthogonal space-time block codes (QOSTBC) is used as MIMO coding with a coding rate of R = 1 . And then QOSTBC is implemented i n a correlated MIMO channel. T o simplify the simulation, equi v alent virtual channel matrix (EVCM) is used in the system’ s simulation. 3.1. Quasi-Orthogonal Space-T ime Block Codes QOSTBC of fers full rate space-time block codes for high number of antennas [39-42]. Basic QOSTBC uses an e xtension of Alamouti Space-T ime Block Codes (STBC). If Alamouti coded signal of x 1 and x 2 is: A = C 2 2 ( x 1 ; x 2 ) = x 1 x 2 x 2 x 1 (3) and Alamouti coded signal of x 3 and x 4 is B = C 2 2 ( x 3 ; x 4 ) = x 3 x 4 x 4 x 3 ; (4) Extended Alamouti Quasi-Orthogonal Space-T ime Block Codes (EA-QOSTBC) of x 1 , x 2 , x 3 , and x 4 is C 4 4 ( x 1 ; x 2 ; x 3 ; x 4 ) = A B B A : (5) Indonesian J Elec Eng & Comp Sci, V ol. 21, No. 3, March 2021 : 1611 1621 Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian J Elec Eng & Comp Sci ISSN: 2502-4752 r 1615 By substituting (3) and (4) to (5), C 4 4 ( x 1 ; x 2 ; x 3 ; x 4 ) = 0 B B @ x 1 x 2 x 3 x 4 x 2 x 1 x 4 x 3 x 3 x 4 x 1 x 2 x 4 x 3 x 2 x 1 1 C C A : (6) EA-QOSTBC in (6) has full rate characteristics with orthogonality of 3 = 4 . 3.2. Corr elated MIMO channel Figure 6. MIMO 4 1 systems using QOSTBC 4 4 with QPSK modulation Simulation system in this paper is sho wn in Figure 6. In an ideal situation, the channel H is inde- pendent for each corresponding transmit and recei v e antennas. Independent or uncorrelated channels pro vide maximum di v ersity in the systems. Recei v ed signal of the MIMO channel is e xpressed as [43, 44]: y = H x + n (7) with H is N r N t channel matrix, x is transmitted signal, and n is additi v e white Gaussian noise (A WGN). Number of transmit and recei v e antennas are N t and N r , respecti v ely . In this research, MIMO channel matrix is: H = h 1 h 2 h 3 h 4 : (8) Independent or orthogonal characteristics in (8) is defined by H and x . MIMO channel matrix H should be independent of each other which means each signal propag ates through an i n de p e nd e nt channel. MIMO encoded transmit signal x should be generated by orthogonal MIMO coding. Correlated MIMO channel is modeled using Kroneck er model as [45]: H = R 1 2 r H i.i.d R 1 2 t (9) with R r is recei v er’ s c o r relation matrix, H i.i.d is independent and identically distrib uted (i.i.d) channel ma- trix, and R is transmitter’ s correlation matrix. Both R t and R r are equi v alently dependent on the antenna’ s parameter . In this research, N r = 1 because there is only one recei v e antenna. 3.3. Equi v alent V irtual Channel Matrix EVCM is used to simplify the MIMO system model. It w orks by transforming coded transm itted signals to the channel [18]. Assuming quasi-static flat-f ading channel, N t 1 can be simplified with recei v e signal v ector [46]: y eq = C h x + v (10) with C h is N c N t STBC coded channel matrix of h , x is transmit signal, v is equi v alent A WGN, and N c is length of MIMO coding. Coded channel matrix is e xpressed as: h = h 1 h 2 h 3 h N c T (11) and transmit signal is e xpressed as: x = x 1 x 2 x 3 x N t T : (12) Sector al dual-polarized MIMO antenna for 5G-NR band N77 base station (M. Muhsin) Evaluation Warning : The document was created with Spire.PDF for Python.
1616 r ISSN: 2502-4752 4. RESUL TS AND DISCUSSION 4.1. Coupling In an array antenna, input from an antenna will af fect output of another antenna. This parameter is described by coupling. If the antenna is inde x ed by i and j , output of antenna i from input of antenna j is s i;j where i 6 = j . F or antenna in Figure 5 the coupling matrix is: S = 0 B B B B B @ s 1 ; 1 s 1 ; 2 s 1 ; 3 s 1 ; 12 s 2 ; 1 s 2 ; 2 s 2 ; 3 s 2 ; 12 s 3 ; 1 s 3 ; 2 s 3 ; 3 s 3 ; 12 . . . . . . . . . . . . . . . s 12 ; 1 s 12 ; 2 s 12 ; 3 s 12 ; 12 1 C C C C C A (13) where s i;j with i = j is return loss of antenna i = j . Ideal v alue of S is for all s i;j . In this case, there are 66 pairs of s ij because there are 66 S ij where i 6 = j . Figure 7. Coupling between antenna 2 and 4 Maximum coupling from frequenc y 3 : 3 4 : 2 GHz is 16 : 90 dB between antenna 2 and 4 at 3.376 GHz. Maximum coupling at 3.7 GHz is 17 dB between antenna 2 and 4 . s 1 ; 4 is sho wn in Figure 7. Coupling between antenna 2 and 4 is relati v ely higher due to opposite feeding. Same v alues are pairs (6 ; 8) and (10 ; 12) . These v alues are then e v aluated by ECC in section 4.3. 4.2. Band width Return loss can be used to define bandwidth with the definition that the antenna w orks with m aximum return loss of 10 -dB. Based on (13), non diagonal elements of S represent coupling and dia go na l elements of S represent return loss. Because of coupling, i t also has an impact on antenna’ s return loss. Final 12 antennas in 3 sectors in section 2.3. ha v e dif ferent bandwidth compared to single antennas in section 2.1. Return loss of 3 sectors antenna in section 2.3. has been sho wn in Figure 8. Limiting return loss from antenna 1 and 12 determined o v erall bandwidth. Antenna 1 has the highest lo wer threshold at 3 : 02 GHz and antenna 2 has the lo west upper threshold at 4 : 89 GHz. The antenna has 1.87 GHz bandwidth based on the return loss threshold 10 dB. Bandwidth of the antenna is decreased d ue to the antenna’ s coupling. It is us u a lly happen on MIMO array antenna. The designed antenna should ha v e a minimum bandwidth of 900 MHz with w orking frequenc y between 3 : 3 4 : 2 GHz. Antenna reaches a bandwi d t h of 1.87 GHz with w orking frequenc y between 3 : 02 4 : 89 GHz. Based on these v alues, the antenna can w ork on the required frequenc y and meet the requirement. 4.3. Corr elation Ideal MIMO antenna has no correlation between its elements. But, in reality , there are correl ations. This correlation is usually measured using en v elope correl ation coef ficient (ECC). ECC is defined by analyzing antennas’ radiation patt ern and polarization in spherical coordinates. ECC between antenna 1 and 2 is defined as [47]: e (1 ; 2) = R R F 1 F 2 d 2 R R F 2 1 d R R F 2 2 d (14) Indonesian J Elec Eng & Comp Sci, V ol. 21, No. 3, March 2021 : 1611 1621 Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian J Elec Eng & Comp Sci ISSN: 2502-4752 r 1617 Figure 8. Port reflection coef ficient of antenna 1 and 12 where F 1 and F 2 is comple x radiation pattern of antenna 1 and antenna 2 , respecti v ely . is azimuth and ele v ation orientation of the antenna. ECC in (14) is v ery comple x and hard to analyze. F or high ef ficienc y antennas, ECC between antenna 1 and 2 can be approached from isolation or coupling parameter as [48]: 1 ; 2 = s 1 ; 1 s 1 ; 2 + s 2 ; 1 s 2 ; 2 2 1 j s 1 ; 1 j 2 + j s 2 ; 1 j 2  1 j s j j j 2 + j s 1 ; 2 j 2  : (15) Non-correlated antenna pairs ha v e ECC of 0 and fully correlated antenna pairs ha v e ECC of 1 . V alue of ECC has a relation with di v ersity g ain. Di v ersity g ain is: G di v (1 ; 2) = 10 q 1 j en v(1,2) j (16) Based on (16), smaller ECC means better di v ersity . There is a requirement of ECC 0 : 5 for a minimum ef fecti v e di v ersity system. ECC comparison of single polarized and dual polarized antenna is sho wn in Figure 9. It has been seen that dual polarized antenna has been pro v en pro viding lo wer correlation compared to single polarized antenna. These characteristics are due to polarization di v ersity in dual pol arized antennas which neighboring antennas ha v e dif ferent orthogonal polarization. a) b) Figure 9. ECC of the: (a) Single polarized antenna, (b) Dual polarized antenna. In the final designed antenna, there are 66 pairs of ECC. Antenna 1 has symmetry with odd numbered antennas and antenna 2 has symmetry with e v en numbered antennas. Considering symmetry of the designed antenna, ECC of antenna 1 with antenna 2 ; 3 ; :::; 12 and antenna 2 with antenna 3 ; 4 ; :::; 12 are enough to represent all 66 pairs. ECC pairs from antenna 1 and 2 are sho wn in Figure 10. Correlations in operation frequenc y 3 : 3 4 : 2 GHz are belo w 10 2 . This correlation v alue is v ery lo w belo w the requirement of ECC Based on t he ECC requirement of 0 : 5 . It means that the antenna can pro vide performance close to non- correlated MIMO Antenna. These correlations are then e v aluated in section 4.4. by using computer simulation of point-to-point communication systems. Sector al dual-polarized MIMO antenna for 5G-NR band N77 base station (M. Muhsin) Evaluation Warning : The document was created with Spire.PDF for Python.
1618 r ISSN: 2502-4752 a) b) Figure 10. ECC of the final antenna: (a) P airs of (1 ; j ) , (b) P airs of (2 ; j ) 4.4. P erf ormance of 4 x 1 System The antenna tested in 4 1 MIMO system in Figure 6. Each sector with 120 angle is serv ed by 4 antennas in a single sector . The simulation used quadrature phase shift k e ying (QPSK) and 4 4 QOSTBC as in section 3.1. Correlation as in section 4.3. is used based on correlated MIMO channels in section 3.2. and EVCM in section 3.3. Figure 11. BER performances of the proposed antenna compared to ideal dully independent antenna and theoretical BER using MRC Performance of the antenna is close to di v ersity order of 3. Theoritically , 4 transmit MIMO antenna with 1 recei v e antenna has performance on di v ersity order of 4. Reference BER for di v ersity order M is [49, 50]: P b = 1 2 M M 1 X m =0 M 1 + m m 1 + 2 m (17) with = s SNR 2 M + SNR : (18) where SNR is a v erage signal to noise ratio. BER performance of the antenna in Figure 11 didn’ t reach a di v ersity order of 4 due to non-orthogonal STBC used. 4 4 QOSTBC has an orthogonality rate of 3 = 4 . It is sho wn in Figure 11 that the BER of the antenna is v ery close to a fully independent antenna as reference. It confirmed that correlation in section 4.3. has v ery close performance to ideal antennas due to v ery lo w correlation. It also confirmed that the designed antenna has v ery good performance which is pro v en by its BER performance, although non-optimum di v ersity order reached due to non-fully-orthogonal STBC. Indonesian J Elec Eng & Comp Sci, V ol. 21, No. 3, March 2021 : 1611 1621 Evaluation Warning : The document was created with Spire.PDF for Python.
Indonesian J Elec Eng & Comp Sci ISSN: 2502-4752 r 1619 5. CONCLUSION Three-sectors dual-polarized antenna for 5G-NR N77 has been proposed. The designed antenna has been e v aluated by its coupling, bandwidth, correlation, and BER performance on 4 1 MIMO systems. The antenna has a bandwidth of 1 : 87 GHz with w orking frequenc y between 3 : 02 GHz and 4 : 89 GHz. Dual-cross polarization is used to minimize coupling in a single sector with maximum coupling of 16 : 90 dB at 3 : 376 GHz between antenna 2 . V ery lo w coupling leads to v ery lo w correlation between antennas. BER performance of the antenna is v ery close to fully independent antenna using 4 4 QOSTBC. Achie v ed di v ersity order using QOSTBC is close to 3 due to non-orthogonal MIMO coding. REFERENCES [1] S. Li, L. Da Xu, and S. Zhao, “5g internet of things: a surv e y , Journal of Industrial Information Inte gra- tion , v ol. 10, pp. 1–9, 2018. [2] D. Do and D. Nguyen, “The maximal sinr selection mode for 5g millimeter -w a v e mimo: Model systems and analysis, Indones. J. Electr . Eng. Comput. Sci , v ol. 7, no. 1, pp. 150–157, 2017. [3] C. X. Ma vromoustakis, G. Mastorakis, and J. M. Batalla, “Internet of Things (IoT) in 5G mobile tech- nologies, Internet of Things (IoT) in 5G mobile technologies. Springer , v ol. 8, 2016. [4] M. R. P alattella, M. Dohler , A. Grieco, G. Rizzo, J. T orsner , T . Engel, and L. Ladid, “Internet of things in the 5g era: Enablers, architecture, and b usiness models, IEEE Journal on Selected Areas in Commu- nications , v ol. 34, no. 3, pp. 510–527, 2016. [5] F . Al-T urjman, E. Ev er , and H. Zahmatk esh, “Small cells in the forthcoming 5g/iot: traf fic modelling and deplo yment o v ervie w , IEEE Communications Surv e ys T utorials, , v ol. 21, no. 1, pp. 28–65, 2018. [6] A. Ijaz, L. Zhang, M. Grau, A. Mohamed, S. V ural, A. U. Quddus, M. A. Imran, C. H. F oh, and R. T af azolli, “Enabling massi v e iot in 5g and be yond systems: Ph y radio frame design considerations, IEEE Access , v ol. 4, pp. 3322–3339, 2016. [7] P . V arzakas, A v erage channel capacity for rayleigh f ading spread spectrum mimo systems, International Journal of Communication Systems , v ol. 19, no. 10, pp. 1081–1087, 2006. [8] Y . Rahayu, I. P . Sari, D. I. Ramadhan, and R. Ng ah, “High g ain 5g mimo antenna for mobil e base sta- tion. International Journal of Electrical Computer Engineering (2088-8708), v ol. 9, no. 1, p. 468, 2019. [9] E. G. Larsson, O. Edfors, F . T ufv esson, and T . L. Marzetta, “Massi v e mimo for ne xt generation wireless systems, IEEE Communications Mag azine , v ol. 52, no. 2, pp. 186–195, 2014. [10] L. Lu, G. Y . Li, A. L. Swindlehurst, A. Ashikhmin, and R. Zhang, An o v ervie w of massi v e mimo: Benefits and challenges, IEEE journal of selected topics in signal processing , v ol. 8, no. 5, pp. 742–758, 2014. [11] T . L. Marzetta, Fundamentals of massi v e MIMO, Cambridge Uni v ersity Press , 2016. [12] E. Bjornson, E. G. La rsson, and T . L. Marzetta, “Massi v e mim o : ten myths and one critical question, IEEE Communications Mag azine, , v ol. 54, no. 2, pp. 114–123, 2016. [13] T . L. Marzetta, “Massi v e mimo: an introduction, Bell Labs T echnical Journal , v ol. 20, pp. 11–22, 2015. [14] M. Agiw al, N. Sax ena, and A. Ro y , “T o w ards connected li ving: 5g enabled internet of things (IO T), IETE T echnical Re vie w , , v ol. 36, no. 2, pp. 190–202, 2019. [15] L. Chettri and R. Bera, A comprehensi v e surv e y on internet of things (IO T) to w ards 5g wireless systems, IEEE Internet of Things Journal , v ol. 7, no. 1, pp. 16-32, 2019. [16] Muhsin, R. P . Astuti, and B. S. Nugroho, “Dual polarized antenna decoupling for 60 ghz planar massi v e mimo, in International Conference on Signals and Systems (ICSig Sys). IEEE , pp. 158–162, 2017. [17] Muhsin and K. Anw ar , Abba dual-cross-polarized antenna decoupling for 5g 16-element planar mimo at 28 ghz, in 2018 2nd International Conference on T elematics and Future Generat ion Netw orks (T AFGEN). IEEE , pp. 1–6 , 2018. [18] M. Muhsin and R. P . Astuti, “Dual-cross-polarized antenna decoupling for 43 ghz planar massi v e mimo in full duple x single channel communications, International Journal of Adv anced Computer Science and Applications , v ol. 10, no. 4, pp. 364–370, 2019. [19] M. Muhsin, W . M. Hadiansyah, A. P . Pramita, and R. D. N. Cah yanti, “Planar dipole mimo array antenna for mobile robot communications at 5.6 ghz, in J2019 4th International Conference on Information T echnology , Information Systems and Electrical Engineering (ICITISEE). IEEE ,pp. 244–248, 2019. [20] A. Alf akhri, M. A. Ashraf, A. Alasaad, and S. Alshebeili, “Design and analysis of compact s ize dual Sector al dual-polarized MIMO antenna for 5G-NR band N77 base station (M. Muhsin) Evaluation Warning : The document was created with Spire.PDF for Python.
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