This paper introduces a new compact Chair-shaped MIMO antenna with two radiating elements and a single layer of frequency-selective surface (FSS) for 5G Sub-6GHz communication systems. They use two techniques, Parasitic element, and (FSS), for isolation and gain enhancement, respectively. The 1 × 2 MIMO antenna using a coplanar waveguide (CPW) fed. Moreover, an FSS array structure consisting of (a 68-unit) Square-shaped structure with Circular Slot (SCS) shaped cells is employed using a new technique (Surround Technique) to enhance the gain and isolation between the elements of the MIMO antenna. The proposed MIMO antenna system is printed on a Rogers 4350B substrate with a thickness of 0.508 mm. The antenna’s performance is evaluated using S-parameters, radiation properties, and MIMO characteristics. The MIMO antenna system works in the Sub 6-GHz 5G band, which ranges from 3 to 6 GHz. Adding the FSS layer enhances the MIMO’s antenna gain to a peak measured gain of 7.96 dBi and it also improves the MIMO antenna’s isolation. The performance metrics of the proposed MIMO antenna were also investigated, including measures values of ECC = 0.004, DG = 9.99 dB, CCL = 0.2 bit/s/Hz, MEG = -3.13 dBi, and TARC = > 0dB) exhibits advantageous antenna characteristics. The observed radiation characteristics of the suggested MIMO antenna system indicate its suitability for the upcoming 5G communication systems.

In this paper, a coplanar waveguide (CPW)-fed patch antenna is fabricated on a layer of metasurface to increase gain. The antenna is fabrication on Roger substrate with a thickness of 0.25mm, with the overall dimension of the proposed design being 45×30×0.25mm³. The size of the patch antenna is 24×14×0.25mm³, and the AMC unit cell is 22×22×0.25mm³. This metasurface is designed based on the split-ring resonator unit cells forming an array of the artificial magnetic conductor (AMC). Meanwhile, the antenna operation on 3.5GHz is enabled by etching a split-ring resonator slot on the ground plane with a small gap to enhance antenna gain and improve impedance bandwidth when integrated with a metasurface. This simulation planer monopole antenna is applied for 5G application. The experimenter test is applied for the antenna performance in terms of return loss, gain, and radiation patterns. The operating frequency range with and without MTM is from 3.41 to 3.68GHz (270MHz) and 3.37 to 3.55GHz (180MHz), respectively, with gain improvements of about 2.7dB (without MTM) to 6.0dB (with MTM) at 3.5GHz. The maximum improvement of the gain is about 42 when integrated with the AMC. The AMC has solved several issues to overcome the typical limitation in conventional antenna design. A circuit model is also proposed to simplify the estimation of the performance of this antenna at the desired frequency band. The proposed design is simulated by CST microwave studio. Finally, the antenna is fabricated and measured. Result comparison between simulations and measurements indicates a good agreement between them.

In recent years, the hybrid branch‐line coupler has attracted much attention due to its appealing features such as of low cost and ease in fabrication for wireless communications. The fifth‐generation cellular networks promise to support several wireless technologies by capitalizing a multitude of frequencies and increase data rates. To achieve that, the butler matrix technique can be used to enhance both bandwidth and data rate with the implementation of beamforming. Conventional hybrid couplers are the main component to build a butler matrix, but they are generally bulky in size and narrow in bandwidth. Moreover, requirements imposed by newer wireless technologies makes the efforts in improving size compactness and bandwidth even more challenging. On the other hand, several techniques have been proposed in literature to solve both issues. This study focuses on the design challenges and issues of hybrid coupler designs and technologies, besides underlining their promising potential. In this context, several techniques for hybrid coupler to achieve the required bandwidth and size reduction are highlighted, such as the T‐shape, meander line, two sections, three‐section, and parallel couple lines.

This paper, presents a 4×4 BM based on four direction switch BM antenna array. The proposed design operated at 3.5 GHz. The use of multi-beam antennas or switched-beam antenna arrays (SAAs) promised users of high-gain and large coverage areas for 5G technologies. The BM was implemented by combining 3-dB BLC, two crossovers, and 45 ^o phase shifters fabricated on the RT5880LZ substrate, with using a triangular slot and T-shape based on the BM design. The proposed design focused on the miniaturization and enhancement of the bandwidth. The return loss and isolation were better than -15 dB at all the ports, according to the simulated and measured result showed that with excellent insertion loss -6.1 ± 2 dB. A fractional bandwidth of 49.7% and the overall dimension were reduced to 56% as compared to the conventional BLC and crossover. Hence, the proposed design of BM performed an excellent size reduction of 80% and improvement bandwidth up to 836 MHz compared to the traditional BM. The switched beam directions were measured at -34 ^o , -40 ^o , +32 ^o and +35 ^o at 3.5 GHz for each input port of 1-4 excitation. The proposed design BM is suitable of 5G application.