A Novel DGS-Integrated Compact Wideband Modified Cloverleaf MIMO Antenna for Multi-Band Wireless Applications

Background. Previously, Many MIMO designs were presented for 4G applications. Out of stated 4G MIMO antennas, few designs presented are not suitable for use in mobile phones due to their large size as compared to the standard sizes of current generation mobile phones. The rest, Ceramic based mobile phone antenna and a multi-band MIMO antenna with PIFA structures have significant heights and non-planner structure which makes them unsuitable for mobile phones as they are getting thinner with advancement in technology. Some MIMO antennas were designed with simpler structure and suitable size but they do not have adequate bandwidth. Here there is a need to develop a MIMO system with an adequate bandwidth to cover all 2G, 3G and 4G bands as well as compact to be suitable for mobile communication.Objective. The purpose of the paper is to design a compact planner MIMO antenna Suitable for Mobile communication with enhanced gain and an enhanced bandwidth to cover all 2G, 3G and 4G bandsMethods.i. A monopole was designed with proper dimensions, which was designed to operate at focus recurrence of 1.8GHz. That covers the wide scope of data transfer capacity from 1.1 GHz to 2.7 GHz at -9 dB reference line. Then an inverted L shape structure known as SIR stub technique is used to enhance the bandwidth.ii. The inverted L shape structure which is extended from the ground plane is put around the monopole which generates the low resonant frequencies and also broadens the bandwidth. Bandwidth is broadened to 0.8 GHz to 3.5 GHz.iii. For the purpose of more impedance matching, a small patch is etched from the ground plane opposite to the feeding and all the parameters are optimizedResults. that lower 0.9GHz radiation pattern is omnidirectional while at higher frequencies it is quasiomnidirectional, a steady gain greater than 2.8dBi over the entire frequency band i.e from .8 GHz to 3.5 GHz, avery high gain of 6.7 dBi at 0.9 GHz. The compact wide band planar MIMO antenna has over 80% efficiency over most of the working recurrence For handy application ECC value less than 0.5 is adequate for mobile phones. The measured ECC is less than 0.36 over complete operating frequency band, which is all right for mobile phonesConclusions. The paper presents compact planner two port MIMO antenna with wideband width and high gain. The proposed antenna achieved a wide bandwidth from 0.8GHz to 3.5GHz covering 2G/3G/4G bands and Wi-Fi (2.45GHz). High isolation between antenna elements, lower ECC and high diversity gain makes the design of the compact planner wide band MIMO antenna a suitable possibility for mobile phone applications.

In this paper, a complementary split ring resonator (CSRR) loaded compact CPW-fed circular shaped monopole UWB antenna with dual band notch characteristics is designed on an FR-4 substrate. The propounded band-notched UWB antenna is integrated with two frequency selective surface layers referred as bandpass frequency selective surface (FSS-1) and reflector (FSS-2) to offer enhanced radiation performance. Bandpass FSS-1 enhances the gain of the antenna by improving directivity and reflector FSS-2 reflects back the backside radiation of the proposed antenna towards the forward direction thereby increasing gain and directivity of the proposed antenna. Furthermore, a two-element orthogonal MIMO antenna is proposed with improved gain using two FSS layers. The complete configuration of the proposed two-element MIMO antenna consists of CSRR-based radiating patches, monopole ground planes and two integrated FSS layers. The proposed MIMO antenna operates in UWB range from 3.46[Formula: see text]GHz to 16.02[Formula: see text]GHz with dual notches at 3.9[Formula: see text]GHz and 7.2[Formula: see text]GHz. Isolation between MIMO elements is greater than 23 dB. Both antennas are fabricated and investigated at 5.9[Formula: see text]GHz for vehicular communications. Maximum gain improvements of 8 dB and 6.4 dB are observed in case of the presented single element and MIMO antenna within the entire operating band due to the integration of dual FSS layers. The diversity performance of the suggested MIMO antenna is investigated by analyzing mean effective gain, envelope correlation coefficient, channel capacity loss and diversity gain parameters. The proposed MIMO antenna is a suitable candidate for vehicular and UWB wireless communication applications.

A novel compact wideband multiple-input-multiple-output (MIMO) antenna is presented in this paper. The MIMO antenna comprises of a wideband neutralization line connected in between two symmetric slotted D-shaped monopoles and a defected ground structure which is cut into the top of the ground plane. With the introduction of wideband neutralization line as a decoupling technique and defected ground plane as an impedance matching element at the input ports of both the antennas, the proposed MIMO antenna achieves −10dB impedance bandwidth of 50.42% (8.90-14.90 GHz) with isolation better than 20 dB.

This article demonstrates a compact wideband four-port multiple-input-multiple-output (MIMO) antenna system integrated with a wideband metamaterial (MM) to reach high gain for sub-6 GHz new radio (NR) 5G communication. The four antennas of the proposed MIMO system are orthogonally positioned to the adjacent antennas with a short interelement edge-to-edge distance (0.19λmin at 3.25 GHz), confirming compact size and wideband characteristics 55.2% (3.25–5.6 GHz). Each MIMO system component consists of a fractal slotted unique patch with a transmission feed line and a metal post-encased defected ground structure (DGS). The designed MIMO system is realized on a low-cost FR-4 printed material with a miniature size of 0.65λmin × 0.65λmin × 0.02λmin. A 6 × 6 array of double U-shaped resonator-based unique mu-near-zero (MNZ) wideband metamaterial reflector (MMR) is employed below the MIMO antenna with a 0.14λmin air gap, improving the gain by 2.8 dBi and manipulating the MIMO beam direction by 60°. The designed petite MIMO system with a MM reflector proposes a high peak gain of 7.1 dBi in comparison to recent relevant antennas with high isolation of 35 dB in the n77/n78/n79 bands. In addition, the proposed wideband MMR improves the MIMO diversity and radiation characteristics with an average total efficiency of 68% over the desired bands. The stated MIMO antenna system has an outstanding envelope correlation coefficient (ECC) of <0.045, a greater diversity gain (DG) of near 10 dB (>9.96 dB), a low channel capacity loss (CCL) of <0.35 b/s/Hz and excellent multiplexing efficiency (ME) of higher than −1.4 dB. The proposed MIMO concept is confirmed by fabricating and testing the developed MIMO structure. In contrast to the recent relevant works, the proposed antenna is compact in size, while maintaining high gain and wideband characteristics, with strong MIMO performance. Thus, the proposed concept could be a potential approach to the 5G MIMO antenna system.

This article presents a dual-band to wideband Frequency Agile (FA) rectangular dielectric resonator (DR) based hybrid MIMO antenna for 5G New Radio (NR) application with connected ground. The DR is made of Al2O3 (εr = 9.8) ceramic material. The FA is achieved through the PIN Diode switches. When the PIN Diode is in an “ON” state, it provides dual bands due to the excitation of TE111 mode. When the PIN Diode is in an “OFF” state, it provides wideband characteristics due to the excitation of TE111 and TE211 modes in the rectangular DR. The isolation and gain are achieved by 20 dB and 4.3 dBi, respectively. The maximum tuning range is 49.36. The MIMO performance characteristics are achieved within the allowable range. A good agreement is achieved between the simulated and measured results. The suggested MIMO antenna is optimized through the various ML algorithms in which Random Forest (RF) ML algorithms achieved the highest accuracy more than 99% compared to other ML algorithms for S-parameters prediction. Hence, it is suitable for 5G NR applications.

The paper addresses the investigations of four elements MIMO antenna with reconfigurable grounds for 5 G NR n3/n1/n40/n41/n77/n79 to X-bands using PIN diodes. Initially, a single unit ultra wideband antenna is implemented, and then it is extended to 2 × 2 MIMO with reconfigurable grounds using one PIN diode. Later, the 4 × 4 MIMO antenna with reconfigurable grounds using six PIN diodes is developed. This study has the novelty that it gives the analysis and design of MIMO antennas switching between unconnected and connected grounds by the method of reconfiguration. The proposed 4 × 4 MIMO is fabricated on FR4 substrate with a volume of 0.485λ0 × 0.326λ0 × 0.0075λ0 mm3, where λ0 is calculated at a lowest resonating frequency. It has operating frequency bands of 1.4–1.6 GHz, 1.75–2.5 GHz and 2.7–13 GHz with connected grounds. The port isolation in the majority of the band is ≤ −15 dB. The inference is included on all the performance metrics. The fabricated MIMO performance is in line with simulated results and hence validates the observations of this research work. So, the proposed MIMO designs are compatible with 5 G wireless applications.

This paper presents a compact self-decoupling dual band MIMO antenna that meets wireless local area network communication standards. The self-decoupling is taken place by purposely using a folded loop-shape element in the MIMO antenna. Furthermore, the feeding point of the element antenna is deliberately selected so as to produce both the two desired frequency bands. The whole loop structure is constructed to produce the lower frequency band while a portion of the loop is resonant to the higher frequency band. The MIMO antenna contains two folded loop-shape elements situated back-to-back with a closed inter-element distance of one-tenth wavelength of the lower band. The novelty of this MIMO antenna is attributed to the achievement of good isolation without using any other supplementary decoupling mechanisms. In addition, the properties of small in size, simple in structure, nearly omni-directional in radiation pattern with moderate radiation gain make the proposed MIMO antenna fully compatible and fairly attractive to the wireless and internet network applications.

A low-profile, compact, microstrip-fed two port MIMO antenna conforming Wi-Fi-5/Wi-Fi-6/V2X/DSRC/ INSAT-C for wireless industrial applications is proposed. In proposed MIMO antenna, the 2-antenna elements are separated by a distance of approximately 7mm, where each antenna element induces a wide resonance at 5.8 GHz with frequency range of (4.85-7.32) GHz covering 10dB impedance bandwidth of the above aforementioned wireless standards. Along with this, the proposed MIMO antenna exhibits an isolation of greater that 15dB throughout the band, omnidirectional radiation patterns, gain greater than 2 dBi and efficiency above 83% throughout the operating bands. Further, to verify the diversity performance of proposed MIMO antenna array, the MIMO performance metrics including Envelope Correlation Coefficient (ECC) and Diversity Gain (DG) are also achieved. The obtained values of bandwidth, isolation, gain, efficiency, ECC, and DG shows that the proposed MIMO antenna is suitable for wireless industrial applications.

This paper presents, compact multiband frequency reconfigurable 3x1 MIMO antenna for cognitive radio applications. The antenna comprises 3-elements reconfigurable MIMO antenna and single element UWB sensing antenna. The frequency reconfigurability range under (S11 ≤ -10 dB) from 7-14.8 GHz using single PIN diode, while the UWB frequency range from 2.597-23.08 GHz. The antenna is designed and optimized to cover such wireless applications such as WiMAX, international telecommunication union (ITU), satellite, and broadband applications. The antenna is optimized using a Genetic Algorithm to operate in the MIMO and cognitive radio systems. The antenna dimensions for 3-elements MIMO antenna are 55 x 65 x 1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr = 4.3, loss tangent tan (δ) = 0.002 and 50 Ω microstrip feed line. The obtained simulated gain is ranging from 2.8-8.25 dB and the maximum simulated gain is 8.25 dB at 8.5 GHz. The return loss, Envelope Correlation Coefficient ECC, and Isolation are obtained to be less than -25 dB, less than 0.018, and less than -17 dB respectively. Detailed simulation results are explored and studied in this research. The CST software is used to simulate and optimize the proposed antenna.

The demand of broadband amplifier has been boosted to meet the requirements of multi-mode and multi-band wireless applications. GaN HEMT is the next generation of RF power transistor technology. In this paper, we have designed a 10W UHF broadband class-AB Power Amplifier (PA) based on GaN HEMT. The proposed amplifier has been designed and developed in the frequency range from 200–500 MHz. A maximum drain efficiency of 71% is achieved.

• The article presents a PIFA MIMO antenna for 5G and WLAN bands. • The proposed antenna is optimized by characteristic mode theory (CMT). • The proposed antenna is analyzed for SAR and MIMO diversity parameters. This article presents a compact, wideband, four-port, multiple-input-multiple-output (MIMO) planar inverted-F antenna (PIFA) for the sub-6 GHz 5G and WLAN bands. The dimensions and strategic placements of the shorting pin, feed plate, and radiator are determined using characteristic mode theory (CMT), as it is a rapid development tool. The current distribution on the antenna structure is solved using an integral solver to investigate and enhance the specific mode of interest. The process is repeated by modifying the antenna structure and applying the solver till the desired modes are generated. Through CMT, two complementary structures are evolved and incorporated into the MIMO antenna for efficient performance. Furthermore, the antennas ground plane is tuned with eight slots, which enhanced the bandwidth, isolation, and directivity (at θ = ± 52 ∘ ). Again, these slot positions have been strategically chosen to keep the ground free for other RF circuitry. The four radiating elements are arranged to exploit the benefits of spatial and pattern diversity, achieving isolation better than 20 dB across the 3.2-5.46 GHz operating band (52.19% fractional bandwidth). The antenna achieves a gain of 5.5–7 dBi with an average total efficiency of 84%. MIMO performance metrics, including envelope correlation coefficient (ECC), diversity gain (DG), and channel capacity loss (CCL), confirm reliable operation. Specific absorption rate (SAR) values are well within international limits (0.558 W/kg at 1 g and 1.24 W/kg at 10 g). Moreover, stable performance is achieved even when operated with a mobile casing. The antenna also demonstrated a data rate of over 25 Gbps for a 15 dB SNR. It shows reliable connectivity delivering >10 Gbps of data over more than 80 m. Thus, the proposed antenna is a strong candidate for next-generation portable wireless devices due to its compactness, simple geometry, and robust performance.

This paper presents a monopole ultra wide band antenna with E- and Inverted L shaped of size 24.99×31 mm2, which exhibit multi-resonant frequencies for multiple wireless applications wireless applications. This antenna can be used to achieve multi resonant frequency, compact antenna size and lead to good impedance matching in the wide dual band which covers 2.20/3.40/5.85 GHz. The designed antenna, which resonates at 2.20 GHz, 3.40 GHz and 5.84 GHz respectively can be used for numerous of wireless applications such as WLAN and WIMAX. The return loss obtained for the corresponding frequency range of 2.2 GHz, 3.37 GHz and 5.84 GHz is −20.48 dB, −18.56dB and −35.93 dB respectively. The Resultant bandwidth obtained from the proposed antenna is 600 MHz (1.98 GHz–2.54 GHz) for 2.20 GHz frequency and 440 MHz (3.19 GHz–3.63 GHz) for 3.40 GHz frequency and 117 MHz (5.35 GHz–6.52 GHz) for 5.84 GHz Respectively. The feeding of the proposed antenna is done with coplanar waveguide, in order make it easy integration with circuits. The Details of the antenna designs, simulated results of the impedance bandwidth, its radiation characteristics and all the corresponding properties have been truly investigated and discussed.

This paper presents the design and experimental validation of a compact triple-band two-port MIMO antenna based on a star-shaped slot-loaded circular radiator for multi-frequency wireless applications. The proposed antenna operates over three distinct frequency bands of 3.1–4.2 GHz, 6.3–8.4 GHz, and 10.1–12.3 GHz, with overall dimensions of 87.5 mm × 35 mm × 1.6 mm (approximately 1.0 λ × 0.4 λ × 0.0187 λ at 3.5 GHz). A key feature of the design is the use of a segmented ground-plane architecture , which effectively confines surface currents and suppresses mutual coupling, enabling high isolation despite a compact edge-to-edge radiator spacing of only 17 mm (≈0.2 λ at 3.5 GHz). As a result, the antenna achieves isolation better than 20 dB in the first band, above 18 dB in the second band, and greater than 11 dB in the third band without employing bulky or complex decoupling structures. Circular polarization is realized in the upper band (10.1–12.3 GHz) through controlled perturbation of higher-order modes using symmetrically placed star-shaped slots, with the axial ratio maintained below 3 dB. The antenna provides a peak gain of up to 8 dBi, with gains ranging from 2 to 8 dBi across the operating spectrum. A fabricated prototype was measured, and the results show good agreement with simulations. The MIMO performance metrics demonstrate excellent diversity characteristics, with ECC &lt; 0.01 , DG ≈ 9.9–10 dB , CCL &lt; 0.4 bits/s/Hz , and TARC &lt; −10 dB across the operating bands, confirming the antenna’s suitability for compact triple-band MIMO systems supporting sub-6 GHz 5G, emerging upper-midband, and X-band wireless applications.

Compact CPW fed Four Port MIMO Antenna for UWB applications with Wi-Fi/ISM/WLAN Band Notch Characteristics

A quad-band two-port MIMO antenna is presented with four operating bands at 2.4, 3.5, 5.8, and 8.2 GHz to serve WLAN, 4G LTE, 5G &amp; ITU applications, respectively. The wide impedance bandwidth of 13.33% (2.28–2.60 GHz), 21.62% (2.98–3.74 GHz), 8.9% (5.58–6.10 GHz) and 4.8% (8.00–8.44 GHz) is achieved at respective operating bands. The antenna also provides circular polarization at 3.5 GHz and 5.8 GHz. It is fabricated on FR4 substrate of 50 × 76 × 1.6 mm3 dimensions. The isolation between both ports is below 28 dB within all four operating bands. The radiation efficiency is about 90% in the first two bands whereas it is about 75% in the remaining two bands. The presented MIMO antenna shows better radiation characteristics along with satisfactory diversity performance. Experimental results of the fabricated prototype validate the simulated results.