This manuscript presents a triple-port ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna designed for wireless communication. The antenna employs automobile window film as a substrate, which is a cost-effective, easily accessible, and ultra-thin material. The proposed structure comprises a monopole antenna featuring a circular patch pattern that is fed by a coplanar waveguide (CPW). Additionally, the internal ground plane has been modified by grooving both sides to form a rectangular slot antenna construction. As a result, the antenna possesses identical dimensions and is equipped with three ports. The antenna exhibits a frequency range spanning from 3.1 GHz to 10.6 GHz across all three ports. Additionally, the | S ₁₁ | at port 1 demonstrates an extensive operating bandwidth of 2.4 GHz to 10.6 GHz with a signal attenuation of less than -10 dB. Consequently, it has the capability to facilitate a diverse range of applications such as ultra-wideband (UWB), Worldwide Interoperability for Microwave Access (WiMAX), Wireless Personal Area Network (WPAN), Wireless Local Area Network (WLAN), and 5G. Furthermore, the antenna exhibits a gain of 5.8 dBi across its entire range, a correlation coefficient below 0.45, and a group latency of under 0.85 ns. The antenna exhibits both omnidirectional and bidirectional radiation patterns across its operational range at ports 1, 2, and 3.

Ultra-wideband (UWB) technology is a crucial facilitator for high-data-rate wireless communication due to its extensive frequency spectrum and low power consumption. Simultaneously, multiple-input multiple-output (MIMO) systems have garnered considerable attention owing to their capability to enhance channel capacity and link dependability. This article discusses the development of small, high-performance MIMO UWB antennas with mutual suppression capabilities to fully use the benefits of both technologies. Additionally, the suggested antenna features a straightforward design and dual-band-notched characteristics. The antenna structure includes two radiating elements measuring 85 × 45 mm². These elements use a rectangular patch provided by a coplanar waveguide (CPW). Double U-shaped slots are incorporated into the rectangular patch to introduce dual-band-notched properties, which help mitigate interference from WiMAX and WLAN communication systems. The antenna is fabricated on a Mylar^® polyester film substrate of 0.3 mm in thickness, with a dielectric constant of 3.2. According to the measurement results, the suggested antenna functions efficiently across the frequency spectrum of 2.29 to 20 GHz, with excellent impedance matching throughout the bandwidth. Furthermore, it provides dual-band-notched coverage at 3.08–3.8 GHz for WiMAX and 4.98–5.89 GHz for WLAN. The antenna exhibits impressive performance, including favorable radiation attributes, consistent gain, and little mutual coupling (less than −20 dB). Additionally, the envelope correlation coefficient (ECC) is extremely low (ECC < 0.01) across the working bandwidth, which indicates excellent UWB MIMO performance. This paper offers an appropriate design methodology for future flexible and compact UWB MIMO systems that can serve as interference-resilient antennas for next-generation wireless applications.

The article presents the design, optimization, and experimental validation of a compact CPW-fed slot antenna that incorporates an Electromagnetic Band Gap (EBG) reflector utilizing interdigitated planar unit cells for multi-band wireless communication applications. The designed 5×5 unit cell EBG reflector is intended to suppress surface waves, hence improving antenna gain, impedance matching, and radiation directivity throughout critical frequency bands centered around 1.5 GHz, 2.45 GHz, 5 GHz, and 5.5 GHz. Comprehensive parametric analyses refine EBG unit cell size and antenna-to-reflector spacing to guarantee reliable performance on an economical FR4 substrate. The constructed prototype attains uniform gain enhancements of around 7 dBi, with operating frequency ranges recorded at 1.45 – 1.6 GHz, 2.3 – 2.6 GHz, 2.7 – 3 GHz, and 4.5 – 6.5 GHz, encompassing principal 5G, Wi-Fi 6/6E/7, and IoT frequency allocations. Validation measurements performed in both anechoic chambers and a realistic metallic cabin environment verify broadband multi-band capability and operational stability under adverse conditions. The antenna’s compact, low-profile design, along with its interoperability with several standards, positions it as a strong option for upcoming high-density wireless systems that demand high capacity, directivity, and low latency. Nevertheless, its benefits, obstacles, including manufacturing complexity and bandwidth constraints, indicate avenues for future research aimed at further downsizing, bandwidth enhancement, and intelligent gain control techniques. The suggested antenna design illustrates the applicability of metasurface-based EBG reflectors for independent multi-band gain regulation, meeting stringent requirements for advanced aircraft and terrestrial wireless communication environments.

This study proposes a high-isolation four-port wideband MIMO antenna array designed for sub-6 GHz 5G, IoT, and radar applications. The array is fabricated on a polycarbonate substrate with overall dimensions of 500 × 500 mm² (ε_r = 2.8, h = 1 mm). Four orthogonally arranged modified circular patches with triangular ground planes and optimized inter-element spacing (D₁ = 90 mm) are employed in the antenna’s design to achieve an impedance bandwidth of 0.7–7.0 GHz (Fractional Bandwidth (FBW) > 163.63%) with |S_ii| < −10 dB across all ports. The measurement results indicate that the inter-port isolation is better than 15 dB (worst-case) across the 0.7–7 GHz band, exceeding 25 dB over 63.5% of the bandwidth (with a peak of approximately 50 dB); the envelope correlation coefficient (ECC) is ultra-low (<0.008); the total active reflection coefficient (TARC) is less than −10 dB for primary multi-port excitations; the mean effective gain (MEG) is balanced (≈−3 dB); and the group delay is consistent (~0.5 ns). With a maximum realized gain of 10 dBi, the antenna exhibits omnidirectional radiation patterns, showing a significant correlation between the simulation (CST Microwave Studio) and measurement results. The proposed antenna is particularly well-suited for use in high-throughput sub-6 GHz 5G base stations and wideband wireless systems, offering superior port isolation through multi-mode resonance without the need for metamaterials and outperforming existing four-port designs.