Claims:1. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications comprising of: Ground Plane; Substrate; height h; Patch; Length L; Width W; and Feed; provides all the dimensions of the antenna for its compact design for 5G Applications.
2. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein antenna is designed on FR4 substrate with a permittivity of 4.4, thickness 1.6 mm and loss tangent of 0.002.
3. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein the antenna consists of three circular shape arcs joined to form a MIMO shape and the radiators are arranged one opposite to other in the substrate.
4. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein in between the two patches rectangular shape slits are placed to improve the isolation among the patches.
5. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein the designed antenna response confirms the resonant frequency at 3.5 GHz with –10dB reference value of return loss with isolation better than -30dB.
6. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein at the frequencies other than the resonant frequency, the antenna has either the inductive or capacitive reactance at higher and lower frequency sides of the resonant frequency respectively.
7. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein the behavior of the proposed design changes from the series resonant circuit to parallel resonant circuit when the frequency reduces far below the resonant frequency, there is a change of effective capacitance reactance to inductive reactance and also increase in resistance peak of the system passing through the zero.
8. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein the radiation efficiency at the resonant frequency is 93%.
9. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein the diversity gain of the proposed MIMO system is approximately 9.998 dB throughout the band.
10. A Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications as claimed in claim 1, wherein the MIMO model shows diversity gain of almost 10 dBi and ECC less than around 0.02.
, Description:The present invention herein is a Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications is explored, a Novel Design Method of Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications is provided in the following layout that explains the entire view of the implementation of the invention that is used in 5G wireless communications.
The present invention, referring to Figure 1, illustrates Front-View of the MIMO Design in the invention disclosed herein comprising of all the dimensions required for compact design. The present invention, referring to Figure 2, illustrates Back-View of the MIMO Design in the invention disclosed herein comprising of all the dimensions required for compact design. The antenna is designed on FR4 substrate with a permittivity of 4.4, thickness 1.6 mm and loss tangent of 0.002. The antenna consists of three circular shape arcs joined to form a MIMO shape and the radiators are arranged one opposite to other in the substrate. In between the two patches rectangular shape slits are placed to improve the isolation among the patches. The design parameters used to design the Compact Two-Element MIMO Patch Antenna at sub 6-GHz band for 5G Applications are listed in the Table 1.
TABLE 1

Antenna Design Parameters used in the present invention.

Parameter L W r1 a b c d e f g h i
Dimensions(mm) 24 45 6 3 4 2.5 2.2 2.6 5 2 2.7 2.9
Parameter j k l r2 εr Wg1 Wg2 Wg3 Lg1 Lg2 Lg3 Lg4
Dimensions(mm) 2.4 6 2.2 2 4.4 15 15 15 8 8 16 16

The simulated S-parameters of proposed MIMO system are shown in Figure 2. The Figure 3 shows that the designed antenna response confirms the resonant frequency at 3.5 GHz with –10dB reference value of return loss with an isolation better than -30dB. The Figure 4 illustrates the variation of input impedance for both real and imaginary parts. The input impedance at the resonant frequency (fr) is ( 45 + j 0 ) Ω. From Figure 4, the proposed system can be modeled as a series resonant circuit consisting of inductance (L), resistor (R) and capacitance (C) connected in series. At the frequencies other than the resonant frequency, the antenna has either the inductive or capacitive reactance at higher and lower frequency sides of the resonant frequency respectively. As the behavior of the proposed design changes from the series resonant circuit to parallel resonant circuit when the frequency reduces far below the resonant frequency, there is a change of effective capacitance reactance to inductive reactance and also increase in resistance peak of the system passing through the zero. To understand the isolation and improved impedance matching simultaneously, another parameter known as surface current distribution is plotted on the ground plane at 3.5 GHz. Port # 1 is excited and port # 2 is matched terminated as indicated in Figure 5. It is identified from Figure 5 (a) that the current is more concentrated on Microstrip feed line and on rectangular stub line which is close to it. This is corroborated from the current distribution on the back side as in Figure 5 (b). The Similar distribution is identified when fed from the other antenna as indicated in Figure 5 (c) and (d). Due to this type of current distribution high isolation and impedance matching between the two elements is accomplished. The length of the ground stub (λg/2) is evaluated using equation (1) at the resonant frequency of 3.5 GHz. Similarly, the rectangular shaped stub length is also evaluated and is approximately λg/2.
L3.5 GHz = 0.5 λg Equation (1)
Where,
Equation (2)
Equation (3)

Where ɛr is the relative permittivity, ɛeff is the effective relative permittivity, λg¬ is the guide wavelength, fr is the resonating frequency and c is the velocity of light. Figure 6 shows the simulated radiation patterns of the MIMO antenna in two principal planes (xz-plane and yz-plane) at 3.5 GHz when element-1 of the arrangement is excited and the element-2 is matched terminated. The co-to-cross polarizations couplings observed at 3.5 GHz are approximately circular. The kth element multiplexing efficiency and total efficiency are evaluated for high amount of SNRs using the relation equations (4) and (5).
Equation (4)
Equation (5)
where ηtotal (k) is the total efficiency, ηradiation (k) is the radiation efficiency of kth element, ρe is the total envelope correlation coefficient (ECC) and ρc is the complex correlation coefficient which is represented by ρc = |ρe|1/2. The simulated radiation efficiency at the resonant frequency is 93%.
To find out the performance of diversity gain, ECC and generalized are obtained using far-field pattern and S-parameters and are given in equations (6) and (7) respectively.
Equation (6)
Where indicates the Complex 3-D radiated far-field pattern

The generalized expression using S-parameters for ECC is given as:

Equation (7)

The diversity gain parameter is evaluated using the mathematical relation:
Equation (8)
The variations of DG and ECC are evaluated using 3-D complex field pattern equation and S-parameters and are depicted in Figure 7. From this, it is noticed that ECC is less than 0.002 which indicates that the MIMO/ diversity performance is within the region of acceptable limit. The diversity gain of the proposed MIMO system is approximately 9.998 dB throughout the band. The variation of TARC with frequency is evaluated using equation (9) and is show cased in Figure 8. The TARC is zero means the total power is radiated in the system while the same is one indicates that either total power of the system is reflected or moved to other ports. It specifies that 0dB or less than 1dB is required in MIMO system. In the MIMO system, maximum required channel capacity and higher amount of data rate can be achieved by enhancing the radiating elements. Channel capacity loss is estimated using equation (10) which is shown in Fig. 7.
Figure 9 shows the waveform response of MIMO system for indoor environment with high-speed transmission. The time-domain side-by-side analysis of the MIMO system is less than 1nsec at the resonant frequency region (3.5 GHz).
Equation (9)
Here the value of θ lies between 0 and 2π.

Closs = -log2det (ΨR) Equation (10)
Equation (11)
Equation (12)
Here ΨR is receiving antenna system correlation matrix
The mean effective gain of MIMO system evaluated by effective power of kth element in the rich fading environment by using radiation patterns and propagation statistics is given by equation 13 and is depicted in Figure 10.

Equation (13)
The above equation satisfies
Equation (14)
Equation (15)
Equation (16)
Here XPR= Cross polarization ratio
Pθ and Pφ are incident powers and angular density functions of θ and φ components. Gθ and Gφ are gain patterns of antenna with θ and φ components. The MEG of MIMO system evaluated for Gaussian and isotropic media at XPR = 0 dB and XPR = 6 dB is listed in Table 2 and Table 3 shows the Performance Parameters of the MIMO present invention disclosed.
TABLE 2

Mean Effective Gains (MEGs) (dB) for MIMO system under different media at various XPR.

Frequency
(GHz) Isotropic Medium Gaussian Medium
MEG
(XPR@ 0dB) MEG
(XPR@ 6dB) MEG
(XPR@ 0dB) MEG
(XPR@ 6dB)
3.5 3.659
5.894
-4.846 7.657

TABLE 3

Performance Parameters of the MIMO present invention disclosed.

Present Invention │S12│
(dB) T.E.A (mm2) GTGC ECC │S12│
(dB)
Present Invention ˂ -35 45 × 24 yes ˂0.002 ˂ -35

The present invention is having MIMO radiator and is designed with three circular ring slots to obtain optimum performance. A small portion of ground plane is considered in a monopole ground plane to explain the response of the MIMO system. The implemented changes in the design are to reduce the isolation and hence obtain the optimum performance of diversity. The MIMO model shows diversity gain of almost 10 dBi and ECC less than around 0.02. From the simulated results, it can be concluded that the mean gain and the radiation characteristic are within the acceptable range. The proposed system can be used for future generation sub 6-GHz for 5G applications for enhanced performance than existing similar systems.