Description:[001] The present invention relates to the textile antenna technology for wearable applications. More particularly, the invention relates to a dual-band textile 2/4/8 - port multiple-input-multiple-output (MIMO) antenna designed for WLAN/Wi-Max/Wi-Fi and X-band applications.
BACKGROUND OF THE INVENTION
[002] The following description provides the information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] Present and future wireless standards necessitate high data rates, driving the adoption of multiple-input multiple-output (MIMO) technology. MIMO offers high data rates and wideband properties, reducing signal fading and interference, thus enhancing communication systems. Compact and flexible antennas are increasingly favoured for wearable applications across various disciplines. Textile antennas must be thin, flexible, lightweight, robust, and compact for seamless integration into wearable devices. When designing textile antennas, factors like structural deformation, location, and fabrication are crucial considerations. In MIMO antenna design, achieving optimal mutual coupling between elements is essential for proper system function. Various techniques, including electromagnetic bandgap (EBG) structures and metamaterials, are employed to reduce mutual coupling.
In the prior art, literature describes several wearable MIMO antennas with high inter-element isolation. Examples include dual-band textile MIMO antennas for WLAN applications and single-layer textile MIMO antennas utilizing the ground plane as a radiator. Additionally, wearable MIMO antennas for ultra-wideband (UWB) applications and wideband rectangular textile MIMO antennas with enhanced isolation have been proposed.
[004] Accordingly, on the basis of aforesaid facts, there remains a need in the prior art to provide a simple low-profile 2/4/8-port MIMO antenna with a common ground plane for wearable applications. The antenna uses rectangle shaped with two opposite F-shaped slots radiator with ground plane and operates in dual-band applications. All antennae’s elements are arranged in orthogonal manner to achieve high port isolation. Minimum isolation of about 25 dB is achieved over the entire application band. The proposed antenna covers the whole WLAN/Wi-Max/Wi-Fi (5/5.2/5.5/5.58 GHz) and X-band (8-12.5 GHz) application bands. In addition to excellent isolation, it also provides highly desirable values of ECC, DG, CCL, MEG, and TARC across the whole useful frequency range. The radiation parameters suggest that the button MIMO antenna is an appropriate fit for specified application areas. The applicability of the MIMO structure in wearable substances is explored in the textile environment. The results indicate that there is no degradation in the application band and port isolation. Therefore, it would be useful and desirable to have a system, to meet the above-mentioned needs.
SUMMARY OF THE PRESENT INVENTION
[005] The present invention introduces a low-profile compact-sized 2/4/8-port MIMO textile antenna is presented for WLAN/Wi-Max/Wi-Fi and X-band applications. The proposed MIMO antenna element consists of a microstrip line-fed rectangle radiator with two F-shaped slots opposite to each other and defective ground plane. In 2-port MIMO antenna radiators are positioned in orthogonal with a common ground plane whereas in 4-port MIMO antenna all radiators are located orthogonal with a X-shaped common ground plane. The proposed 8-port MIMO antenna is arranged with a combination of 2-port and 4-port MIMO antenna.
[006] The antenna's investigation revealed an optimal frequency range of 4.17 GHz to 6.10 GHz and 8.22 GHz to 12.70 GHz, which matches the requirements for WLAN/Wi-Max/Wi-Fi (5/5.2/5.5/5.8 GHz) and X-band (8 GHz - 12.5 GHz). Port isolation exceeds 25 dB across the whole application range. Given the importance of diversity features in evaluating MIMO antennas, we thoroughly analysed all of these factors. The ECC is to be less than 0.01, and the CCL is less than 0.13 b/s/Hz. A low ECC suggests a strong diversity gain (DG) and lower correlation between antenna components.
[007] The mean effective gain (MEG) is reasonable, measuring approximately ±0.3 dB. The antenna's TARC significantly verifies its normal impedance characteristics. The radiation patterns stay stable across the whole employed frequency range. Ansys HFSS is used to simulate, analyse, and optimize the assembly. The simulated and measured results show a near alignment of features.
[008] In this respect, before explaining at least one object of the invention in detail, it is to be understood that the invention is not limited in its application to the details of set of rules and to the arrangements of the various models set forth in the following description or illustrated in the drawings. The invention is capable of other objects and of being practiced and carried out in various ways, according to the need of that industry. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
[009] These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference are made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[010] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
[011] FIG. 1, illustrates the proposed antenna with design parameters, in accordance with an embodiment of the present invention.
[012] FIG. 2, illustrates the simulated (a) reflection coefficient (b) peak realized gain and efficiency of proposed antenna, in accordance with an embodiment of the present invention.
[013] FIG. 3, illustrates the simulated reflection coefficient (a) Effect of L1 (b) Effect of L2, in accordance with an embodiment of the present invention.
[014] FIG. 4, illustrates the simulated reflection coefficient (a) Effect of L3 (b) Effect of L4, in accordance with an embodiment of the present invention.
[015] FIG. 5, illustrates (a) Effect of Lg on simulated reflection coefficient (b) Comparison of simulated and measured reflection coefficient, in accordance with an embodiment of the present invention.
[016] FIG. 6, illustrates the Fabricated prototype of basic antenna (a) top view (b) bottom view, in accordance with an embodiment of the present invention.
[017] FIG. 7, illustrates the layout structure of two-port MIMO antenna (W7 = 2mm, L7 = 60mm, L8 =26.5mm), in accordance with an embodiment of the present invention.
[018] FIG. 8, illustrates the Simulated (a) S-parameters (b) Gain and efficiency of two-port MIMO antenna, in accordance with an embodiment of the present invention.
[019] FIG. 9, illustrates the Simulated (a) DG & ECC (b) CCL & MEG of proposed two-port MIMO antenna, in accordance with an embodiment of the present invention.
[020] FIG. 10, illustrates the (a) simulated TARC at different phase angles (b) comparison of simulated and measured s-parameters, in accordance with an embodiment of the present invention.
[021] FIG. 11, illustrates the Fabricated protype of 2-port MIMO antenna (a) front view (b) back view, in accordance with an embodiment of the present invention.
[022] FIG. 12, illustrates the layout structure of 4-port orthogonal MIMO antenna (a) w/o common ground (b) with common ground (W8=L9=60 mm, L10= 45mm), in accordance with an embodiment of the present invention.
[023] FIG. 13, illustrates the simulated (a) reflection coefficient (b) isolation of 4-port MIMO antenna, in accordance with an embodiment of the present invention.
[024] FIG. 14, illustrates the surface current distribution of proposed 4-port MIMO antenna at (a) 5.2 GHz (b) 9.28 GHz, in accordance with an embodiment of the present invention.
[025] FIG. 15, illustrates the simulated (a) Efficiency & peak gain (b) ECC, in accordance with an embodiment of the present invention.
[026] FIG. 16, illustrates the simulated (a) DG (b) CCL & MEG of the 4-port MIMO with common ground, in accordance with an embodiment of the present invention.
[027] FIG. 17, illustrates the (a) simulated TARC at different phase angles (b) comparison of simulated & measured s-parameters, in accordance with an embodiment of the present invention.
[028] FIG. 18, illustrates the simulated E-filed radiation pattern at (a) 5.2 GHz (b) 9.2 GHz, in accordance with an embodiment of the present invention.
[029] FIG. 19, illustrates the fabricated protype of proposed 4-port MIMO antenna (a) top view (b) bottom view, in accordance with an embodiment of the present invention.
[030] FIG. 20, illustrates the layout structure of 8-port MIMO antenna (L11=130 mm, L12=10mm, L13= 57 mm, R1=5mm), in accordance with an embodiment of the present invention.
[031] FIG. 21, illustrates the simulated (a) reflection coefficient (b) isolation, in accordance with an embodiment of the present invention.
[032] FIG. 22, illustrates the simulated isolation between ports of proposed antenna, in accordance with an embodiment of the present invention.
[033] FIG. 23, illustrates the simulated (a) isolation (b) Gain and efficiency of the proposed antenna, in accordance with an embodiment of the present invention.
[034] FIG. 24, illustrates the simulated (a) MEG (b) ratio of MEG’s of the proposed antenna, in accordance with an embodiment of the present invention.
[035] FIG. 25, illustrates the simulated ECC of the proposed 8-port MIMO antenna, in accordance with an embodiment of the present invention.
[036] FIG. 26, illustrates the simulated ECC of the proposed 8-port MIMO antenna, in accordance with an embodiment of the present invention.
[037] FIG. 27, illustrates the simulated DG of the proposed 8-port MIMO antenna, in accordance with an embodiment of the present invention.
[038] FIG. 28, illustrates the simulated DG of the proposed 8-port MIMO antenna, in accordance with an embodiment of the present invention.
[039] FIG. 29, illustrates the simulated TARC of the proposed 8-port MIMO antenna, in accordance with an embodiment of the present invention.
[040] FIG. 30, illustrates the (a) simulated CCL (b) comparison of simulated and measured s-parameters, in accordance with an embodiment of the present invention.
[041] FIG. 31, illustrates the fabricated prototype of 8-port MIMO antenna, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[042] While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described and are not intended to represent the scale of the various components. Further, some components that may form a part of the invention may not be illustrated in certain figures, for ease of illustration, and such omissions do not limit the embodiments outlined in any way. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claims. As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one” and the word “plurality” means “one or more” unless otherwise mentioned. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention.
[043] In this disclosure, whenever a composition or an element or a group of elements is preceded with the transitional phrase “comprising”, it is understood that we also contemplate the same composition, element or group of elements with transitional phrases “consisting of”, “consisting”, “selected from the group of consisting of, “including”, or “is” preceding the recitation of the composition, element or group of elements and vice versa.
[044] The present invention is described hereinafter by various embodiments with reference to the accompanying drawings, wherein reference numerals used in the accompanying drawing correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the following detailed description, numeric values and ranges are provided for various aspects of the implementations described. These values and ranges are to be treated as examples only and are not intended to limit the scope of the claims. In addition, a number of materials are identified as suitable for various facets of the implementations. These materials are to be treated as exemplary and are not intended to limit the scope of the invention.
[045] The present invention relates to the low-profile 2/4/8-port MIMO antenna designed specifically for wearable applications, featuring a common ground plane. Utilizing rectangular shapes with opposing F-shaped slots as radiators, the antenna operates effectively in dual-band scenarios. The arrangement of antenna elements in an orthogonal configuration ensures robust port isolation, achieving a minimum isolation of approximately 25 dB across the entire frequency band of interest. Covering the entire spectrum of WLAN/Wi-Max/Wi-Fi (5/5.2/5.5/5.58 GHz) and X-band (8-12.5 GHz) applications, the proposed antenna demonstrates exceptional performance metrics including envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), mean effective gain (MEG), and total active reflective coefficient (TARC). Radiation parameter analysis underscores the suitability of the button MIMO antenna for targeted application domains. Furthermore, the feasibility of integrating the MIMO structure into wearable materials is explored within a textile environment, revealing no degradation in performance within the application band and port isolation.
[046] ANTENNA GEOMETRY AND ANALYSIS:
The dual-band antenna is built on a flexible substrate made of jeans material with the following properties: dielectric constant of 1.77, loss tangent of 0.083, bulk conductivity of 0.034 S/m, and thickness of 1.4 mm. A rectangular patch (Ant1) with a defective ground plane emits in the frequency range of 7.2 GHz to 11.57 GHz. It resonates at 9.57 GHz with a return loss of -17.9 dB. An F-shaped etching is added to the left side of a rectangular patch antenna (Ant2) to form a dual-band antenna that operates at frequencies ranging from 4.2 GHz to 6.2 GHz and 7 GHz to 11.6 GHz. An extra inverted-F shape is added to the right side of the patch (Ant3), allowing the antennas to radiate in dual-band applications at 5.75 GHz - 8.5 GHz and 9.12 GHz - 11.62 GHz. The antenna has been upgraded from Ant4 to Ant5 to enable proper functionality in WLAN/Wi-Max/Wi-Fi applications (5/5.2/5.5/5.8 GHz) and all X-band applications (8 GHz-12.5 GHz). Figure 1 shows the evolution of the antenna. The proposed antenna is used in dual-band applications. Band 1 resonates between 4.51 GHz and 6.14 GHz, with a resonance frequency of 5.2 GHz, and Band 2 resonates between 8.21 GHz and 12.61 GHz, with a resonant frequency of 11.85 GHz as shown in Fig. 2(a).
[047] Fig.2(b) illustrated the simulated peak realized gain and radiation efficiency of proposed antenna, for entire operating bands gain of the radiator is positive and maximum gain obtained at 5.57 GHz which is 2.33 dB as well as radiation efficiency is more than 55 % throughout operating frequency. The design parameters and dimensions are listed in the table 1.
[048] Parametric analysis
A parametric analysis of the designed antenna is presented in this section, considering the main design variables and their effect on the antenna behaviour: the length of the L1, the bottom (L2, L3) and middle (L4) length of F- shaped slot, and the width of the ground plane (Lg).
Change in L1
In Fig.3 (a) the simulated reflection coefficient of the flexible jean antenna for different lengths L1 (see Fig. 1) of the proposed antenna is shown. The resonant frequency of the L1 slot is tuned by its length, which slightly also modifies the resonant frequency of the antenna. Lower band resonant frequencies are shifted to lower frequencies for increasing values of L1 whereas in upper band return loss value is increased at higher frequencies. Increasing L1 also modifies the input impedance of the structure, since a thinner slot corresponds to higher values of the input impedance. As shown in the plot, the optimal value of L1 = 16.5 mm has been chosen for the final antenna layout.
Change in L2 and L3
The choice of both bottom lengths of F-slots on left and right side of rectangle patch plays a significant role in the design of the proposed antenna for on-body applications. In fact, the bottom of left side slot (L2) effects the upper band return loss as well as bandwidth, the effect is negligible on the lower band as shown in Fig. 3 (b). The impact of L3 on both bands are insignificant as depicted in Fig. 4 (a).
Change in L4 and Lg
The length of the middle f-shaped slot (L4) and width of the ground plane (Lg) strongly influences operating bands as shown in Fig. 4(b) and Fig. 5 (a) respectively. The effect of L4 is more on the lower cutoff frequency of upper band and negligible effect on lower band bandwidth for increased value of L4. The width of the ground plane (Lg) strongly influences on both bands. As value increases the resonance frequency is shifted to lower frequencies in lower operating band but in upper band resonance frequency never change and bandwidth is also increased on both operating bands. Validation of simulated and measure reflection coefficient of basic antenna is shown in Fig.5(b), there is slight difference in measured results as compared to simulated because of manual fabrication and soldering issues. The fabricated protype of basic antenna on the jeans material is depicted in Fig.6.
[049] ANALYSIS OF TWO-PORT MIMO ANTENNA
Two types of two-port MIMO antennas are proposed: a side-by-side (SBS) construction and an orthogonal structure with a common ground, as illustrated in Figure 7. The simulated S-parameters for both structures are illustrates in Figure 8 (a). Both structures resonate in dual-band applications at the same frequencies and bandwidths. Band 1 has a resonance frequency of 5.2 GHz and ranges from 4.51 GHz to 6.14 GHz. Band 2 has a resonance frequency of 11.85 GHz and resonates from 8.21GHz -12.61 GHz, as shown in Fig. 8(a). For practical purposes, all antennas in a MIMO system must share a common ground, hence an orthogonal structure with a common ground is developed. SBS provides 18 dB of isolation between antennas. The isolation in the orthogonal approach is greater than 30 dB for the lower band and 25 dB for the upper band, as shown in Fig. 8 (a). Hence orthogonal approach provides more isolation among the antennas as compared to SSB structure. Figure 8 (b) shows the simulated peak realized gain for orthogonal and SBS topologies, which are 4 dB and 3 dB, respectively. The radiation efficacy of the proposed orthogonal technique is around 85% for both operating bands, whereas the SBS approach is 80%, as illustrated in Figure 8 (b).
Diversity characterstics of two-port MIMO antenna
Envelop Correlation Coefficient (ECC), Diversity Gain (DG), Mean Effective Gain (MEG), Channel Capacity Loss (CCL), and Total Active Reflection Coefficient (TARC) are critical variables for determining the capacity and functionality of MIMO antennas. ECC is used to determine the correlation between antenna elements. To improve the variety of MIMO antenna elements, the Error Correction Code (ECC) should be decreased. The ECC must be less than 0.5 to be regarded acceptable. The envelope correlation coefficient (ECC) ?eij for multi-port MIMO antennas was calculated using simulated 3-D radiation patterns using the equation [25]. i and j are port numbers, XPR is cross-polarization ratio, and P? and P? are the angular density function components of the incoming wave in the ? and ? directions. The diversity gain (DG) of MIMO antennas can be calculated using the equation below.
DG = 10v(1-?ECC?^2 )
Fig. 9(a) illustrates the comparison between ECC and DG of the proposed 2-port MIMO antennas. The Envelop Correlation Coefficient (ECC) is significantly modest (<0.01) across the whole impedance bandwidth. Moreover, the directive gain of the antenna exceeds 9.9dB across the whole impedance bandwidth. The suggested antenna has a smaller Envelop Correlation Coefficient (ECC) and a greater Directivity Gain (DG).
[050] The channel capacity of the MIMO system increases linearly as more antenna elements are added. Nonetheless, there are losses due to the correlation between the Multiple Input Multiple Output (MIMO) channels. The interaction between elements in MIMO channel systems reduces capacity. As a result, the CCL plays an important role in defining the channel capacity of the MIMO system. Figure 9(b) depicts the CCL of the orthogonal structure of MIMO antenna. In a MIMO system, the Channel Capacity Loss (CCL) should be less than 0.4 bits per second per hertz. The antenna's CCLs are consistently less than 0.2bps/Hz throughout all operating bands. The antenna provides good diversity performance. MEG is a crucial parameter for evaluating the performance of MIMO antennas. The MEG is the ratio of the average power received by the diversity antenna to the average power received by the isotropic antenna in multipath fading scenarios. To maintain comparable power levels, the ratio between MEGs should be between ± 0.3 dB. Fig.9(b) illustrates the simulated ratio between MEGs approaching zero for orthogonal two-port MIMO antenna configuration.
The Total Active Reflection Coefficient (TARC) is calculated as the square root of the ratio of total reflected power to total incoming power and the apparent return loss of the complete MIMO antenna system. Figure 9(a) illustrates the TARC of the antenna. Figure 10 (a) demonstrates that the Total Active Reflection Coefficient (TARC) remains below -10dB across the full working band of the dual-band system. Comparison of simulated and measured s-parameters are shown in Fig.10(b), from the graph both results are similar to each other.
[051] ANALYSIS OF FOUR-PORT MIMO ANTENNA
The geometrical layout structure of 4 -port MIMO antenna with and without common ground is shown in Fig.12. The simulated reflected coefficient and isolation between the ports of the antennas are depicted in Fig.13 (a,b) respectively. Proposed antenna structures are radiating in same frequency bands with identical bandwidths, which are 4.46 GHz - 6.28 GHz (1.82 GHz) and 8.37 GHz – 12.68 GHz (4.31 GHz) with a resonance frequency of 5.2 GHz and 9.28 GHz respectively is illustrates in Fig.13 (a). The isolation between ports of proposed 4-port orthogonal with common ground is more than 25 dB as shown in Fig.13 (b). Isolation can be visualized by using surface current distribution as shown in Fig. 14. Maximum amount of current is concentrated inside of the patch and less current is passing nearby radiating elements. The simulated peak and radiation efficiency of the antenna is shown in Fig.15 (a), maximum peak gain of 5 dB is achieved at 12 GHz, and the efficiency remains above 85% across the intended frequency range.
Diversity characteristics of four-port MIMO antenna
Envelop Correlation Coefficient (ECC), Diversity Gain (DG), Mean Effective Gain (MEG), Channel Capacity Loss (CCL), and Total Active Reflection Coefficient (TARC) are critical variables for determining the capacity and functionality of MIMO antennas. The simulated ECC and DG of the proposed antenna is within the acceptable range as shown in Fig. 15 (b) and Fig. 16 (a) respectively. The simulated CCL and ratio of MEGs of the proposed 4-port MIMO antenna is depicted in Fig.16 (b), from that CCL < 0.05 bits/sec/Hz and ratio of MEG is ± 0.3 dB. TARC is a crucial measure used to assess the effectiveness and efficiency of Multiple Input Multiple Output (MIMO) antennas. Mutual coupling is a critical factor in assessing the performance of MIMO antennas. TARC is utilized for analysing mutual coupling. The simulated TARC24 at different phase angles is shown in Fig.17 (a), the resonance frequency is never changing w.r.t angle which is demonstrated that wide-angle stability of the proposed orthogonal antenna. The comparison of both simulated and measured s-parameters are shown in Fig.17(b), which are like each other for desired band of frequencies. The simulated E-field radiation pattern for both co and cross polarization at resonance frequencies as shown in Fig.18. The co-polarization is more than 15 dB than the cross-polarization at desired band of frequencies i.e isolation is enhanced at the frequencies and fabricated prototype of orthogonal 4-port MIMO antenna with common ground is depicted in Fig.19.
[052] ANALYSIS OF EIGHT-PORT MIMO ANTENNA
The geometrical layout of the proposed orthogonal 8-port MIMO antenna as shown in Fig.20, it is observed that all antennas are orthogonal to each other when ever moving clockwise or anti-clockwise direction. The proposed antenna exhibits dual-band characteristics for each of the individual ports as shown in Fig.21 (a). Among the all-ports isolation is more than 26 dB for both operating bands as illustrated in Fig. 21 (b)- 23 (a). The peak gain of the proposed antenna is 4.12 dB at 9.85 GHz and radiation efficiency of the antenna for desired band of frequencies is more than 80% as shown in Fig.23 (b).
Diversity characteristics of Eight-port MIMO antenna
The performance of MIMO antenna can be analysed by using diversity performance parameters. The simulated individual MEG and ratio of the MEGs are shown in the Fig. 24. Individual MEG of each port is less than the -6 dB and the ratio is near to 0 dB for both desired bands. The simulated ECC for all ports of the proposed 8-port MIMO antenna is less than 0.01during the desired frequency band as shown in Fig. 25-26. The simulated DG of antenna is near to 10 dB for entire band of frequencies as shown in Fig. 27-28. TARC at two different ports of the 8-port antenna is shown in Fig.29, in which the resonant frequency is never change w.r.t to different phase angles. The CCL of the proposed antenna during the operating bands <0.1 bits/sec/Hz a shown in the Fig.30 (a). The simulated and measured s-parameters are synchronous to each other during the desired band of frequencies as illustrated in Fig.30 (b). The fabricated orthogonal 8-port MIMO antenna is shown in Fig.31.The summary of all proposed antennas are listed in table 2.

The comparison of proposed MIMO antenna with pervious literature work is shown in table.3.

[053] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-discussed embodiments may be used in combination with each other. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description.
[054] The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the embodiments.
[055] While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.
, Claims:1. A dual-band textile 2/4/8 - port multiple-input multiple-output (MIMO) antenna comprising:
a flexible substrate made of jeans material with a dielectric constant of 1.77, a loss tangent of 0.083, bulk conductivity of 0.034 S/m, and a thickness of 1.4 mm;
a rectangular patch antenna (Ant1) emitting in the frequency range of 7.2 GHz to 11.57 GHz with a resonant frequency of 9.57 GHz and a return loss of -17.9 dB;
a F-shaped etching added to the left side of a rectangular patch antenna (Ant2) forming a dual-band antenna operating at frequencies ranging from 4.2 GHz to 6.2 GHz and 7 GHz to 11.6 GHz;
an additional inverted-F shape added to the right side of the patch (Ant3) enabling radiation in dual-band applications at 5.75 GHz - 8.5 GHz and 9.12 GHz - 11.62 GHz; and
an upgraded antenna (Ant5) enabling functionality in WLAN/Wi-Max/Wi-Fi applications (5/5.2/5.5/5.8 GHz) and all X-band applications (8 GHz-12.5 GHz).
2. The antenna as claimed in claim 1, wherein the antenna operates effectively in dual-band scenarios, resonating between 4.51 GHz and 6.14 GHz in Band 1, and between 8.21 GHz and 12.61 GHz in Band 2.
3. The antenna as claimed in claim 1, wherein the two-port MIMO antenna structure, comprising: a side-by-side (SBS) construction and an orthogonal structure with a common ground; a SBS construction providing 18 dB of isolation between antennas, and an orthogonal structure providing greater than 30 dB isolation for the lower band and 25 dB for the upper band.
4. The two-port MIMO antenna as claimed in claim 3, wherein the the orthogonal structure demonstrates a simulated peak realized gain of 4 dB and a radiation efficiency of around 85% for both operating bands.
5. The antenna as claimed in claim 1, wherein the four-port MIMO antenna structure comprising: a radiating in the frequency bands of 4.46 GHz - 6.28 GHz and 8.37 GHz – 12.68 GHz with a resonance frequency of 5.2 GHz and 9.28 GHz, respectively and an isolation between ports of greater than 25 dB.
6. The four-port MIMO antenna as claimed in claim 5, wherein the four-port MIMO antenna exhibits a simulated peak gain of 5 dB and a radiation efficiency above 85% across the intended frequency range.
7. The antenna as claimed in claim 1, wherein the eight-port MIMO antenna structure, exhibiting dual-band characteristics for each of the individual ports with isolation of more than 26 dB for both operating bands.
8. The eight-port MIMO antenna as claimed in claim 7, wherein the eight-port MIMO antenna demonstrates a simulated peak gain of 4.12 dB at 9.85 GHz and a radiation efficiency of more than 80% for the desired frequency range.