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.

This paper presents a dual-mode characteristic for miniaturized metamaterial with a unit cell design based on an interdigital coplanar waveguide (ICPW) combined with trisection step-impedance to enable the three resonant frequency responses of 1.8 GHz, 3.7 GHz, and 5.8 Hz. In addition, the unit cell dimensions can be reduced from λ/2 to λ/8 due to the fact that the ICPW technique based on the CPW structure enhances the capacitive load between the transmission line and the side ground, thereby increasing the slow-wave on the transmission line. In addition, the trisection step- impedance will be incorporated and applied to the transmission line and cooperate with the unit cell structure’s capacitive load to effectively resonate at the desired frequency location. Moreover, the unit cell structure designed with the method above must be utilized as a double layer in which the structure on both sides is identical. The back structure will property the rod, which will cause the permittivity and permeability to be negative and closer to zero. This property of the proposed material allows for its utilization as a director at its first resonant frequency and as a reflector at the subsequent second and third resonant frequencies. The proposed metamaterial employs FR-4 printed circuit boards with a dielectric constant (ε _r ) of 4.4, a substrate thickness of 1.6 mm, a conductor thickness of 0.035 mm, and a loss tangent (tanδ) of 0.04. The unit cell size is approximately 14×14 mm ² . The unit cell will then be arranged as a 7×7 array with an overall dimension of 98×98 mm ² to evaluate an antenna’s performance. An antenna used for testing the proposed unit cell is a dipole antenna that propagates at a single frequency corresponding to the unit cell’s resonant frequency. At all resonant frequencies, the impedance matching of the dipole is less than -10 dB. At 1.8 GHz, 3.7 GHz, and 5.8 GHz, the dipole antenna gain is 2 dBi, 2.06 dBi, and 1.95 dBi, respectively. Moreover, the dipole antenna’s characteristics were simulated using the CST program in conjunction with the unit cell array. Based on the simulation and measurement results, the antenna with the unit cell array exhibits an impedance bandwidth of less than -10 dB at frequencies of 1.8, 3.7, and 5.8 GHz. The gains obtained from the simulation results are 5.49 dBi, 8.21 dBi, and 7.87 dBi, while the measurement results show gains of 5.73 dBi, 8.19 dBi, and 7.79 dBi, respectively. The simulated and measured outcomes demonstrate a substantial correspondence.

This paper presents a multiband director based on the frequency selective surface (FSS) unit cell structure using the double layer with interdigital CPW (ICPW) technique. The unit cell consists of the front and the back. The front part has been designed using an ICPW technique based on a coplanar waveguide structure to enhance the capacitance between the transmission line and the semi-ground. The overall structural dimension of the unit cell can be designed to be smaller than the conventional range of λ/2 to λ/8, due to the influence of the slow wave effect on the capacitance of the structure. The back part is the inverted layer of the front, which alternates between substrate and copper. It is composed of a square loop resonator with a double meandering line. The capacitance generated by a double meander line enhances the capacitance in the front part, which influences the control of all resonant frequencies and increases the slow wave on the double-layer unit cell structure, resulting in a significantly reduced dimension. The resonance frequencies for the designs are 1.8 GHz (LTE), 3.7 GHz (Wi-MAX) and 5.2 GHz (WLAN), respectively. According to simulation results, the FSS can transmit all resonant frequencies. It has an overall dimension of 10.93 mm ×11.48 mm. In addition, the FSS unit cell has been arranged as a 7×7 array for use as a director. The dimensions are 73.48 mm ×77.38 mm. The FSS director will be evaluated utilizing an omnidirectional dipole antenna at the same resonant frequency as the FSS unit cell. According to both the simulated and measured outcomes, the impedance matching value is below -10 dB at the three resonant frequencies. The FSS director equipped with a dipole antenna exhibits bidirectional propagation characteristics across all resonant frequencies. The antenna gains for simulation are 3.45 dBi, 3.05 dBi, and 3.72 dBi, while the antenna gains for measurement are 3.05 dBi, 2.98 dBi, and 3.12 dBi. The findings indicate a high level of concurrence.

This paper presents a triband operation enhancement based on multimode analytics of a monopole antenna designed by combining a rhombic ring radiator with a strip on a top layer and a fractal ring resonator placed at the bottom layer. The proposed antenna can achieve triband operation to support the modern wireless communication systems. The antenna size is approximately 36 × 52 mm², which is quite compacted compared with the revised antenna. The simulation and measurement results are in good agreement. The antenna covers the operating bands at 22.22%, 9.8%, and 31.27% at the resonant frequencies of 1.8 GHz, 2.45 GHz, and 3.71 GHz, respectively, to support the application bands of LTE 1800, WLAN IEEE802.11b/g, WiMAX, and IMT Advanced Systems (5G). The average gain of the antenna is about 2 dBi. Also, the radiation patterns are omnidirectional for all operating frequencies.

This paper presents microstrip array antennas applied to a technique of fractal geometry. The presented antenna is designed at the operation frequency 2.45 GHz, which is used in application of wireless local area network. The presented array antennas have equal space between centers of each element, which is 0.5 lambdao. It has been found that dimension and back lobes of the presented fractal array antenna are reduced comparing with the array of normal square patch array antenna. Obviously, the radiation patterns of the presented array antennas are still similarly to the normal square patch array antenna. The properties of the antennas for instance return losses, radiation patterns and gain are determined via numerical simulation and measurement.