Reconfigurable metamaterial structure for 5G beam tilting antenna applications

In this paper, we propose a metamaterial (MTM) structure with a reconfigurable property designed to operate at the millimetre-wave (mm-wave) spectrum. Four switches are used to achieve the reconfigurable property of the MTM with two configurations. These two configurations exhibit different refractive indices, which used to guide the radiation beam of the antenna to the desired direction. The proposed planar dipole antenna operates at the 5th generation (5G) band of 28 GHz. The electromagnetic (EM) rays of the proposed antenna pass through different MTM configurations with different phases, subsequently results in the tilting of the radiation beam toward MTM configuration of high refractive index. Simulated and measured results of the proposed antenna loaded by MTM demonstrate that the radiation beam is tilted by angles of +34° and −31° in the E-plane depending on the arrangement of two MTM configurations onto the antenna substrate. Furthermore, the gain is improved by 1.7 and 1.5 dB for positive and negative tilting angles, respectively. The reflection coefficients of the antenna with MTM are kept below −10 dB at 28 GHz

Substrate integrated waveguide cavity backed frequency reconfigurable antenna for cognitive radio applies to internet of things applications

In this article, a new multiband frequency reconfigurable substrate integrated waveguide cavity slot antenna was designed using Computer Simulation Technology software tool for addressing the specific design challenges posed by the internet of things (IoT) based cognitive radio networks. Reconfiguration of frequency bands is achieved using PIN diodes. The antenna resonated at 2.624, 2.664, 2.720, 2.752, 4.304, 4.532, 4.556, 5.236, 5.304, 5.368, 5.332, and 5.392 GHz. The resonant frequency capability and radiation performance are demonstrated by both simulations and measurements. The simulated and measured results were in agreement. The higher efficiency, gain and average bandwidth obtained are 90%, 8.2 dBi and 65 MHz, respectively. The compactness, integrity, reliability, and performance at various operating frequencies make the proposed antenna a good candidate for IoT applications

Convertible Bandstop to Allpass Filter using Defected Ground Structure with Ideal Switch for Millimeter-Wave Band in 5G Application

According to this study, a defective ground structure (DGS) with an ideal switch can be used to create a bandstop to allpass filter for 5G applications. The redesigned Hairpin DGS's bandstop and allpass responses are mathematically investigated in this paper. Utilising an ideal switch via open circuit and short circuit conditions on DGS, the convertible filter is operated. Therefore, the filter's performance in terms of return loss, attenuation, and insertion loss is simulated. As a result, the filter operates at 25.875 GHz in open circuit condition with a narrowband (2.16 GHz) bandstop response at 10 dB and a maximum attenuation of 29.5 dB, and at 26 GHz with a wideband allpass response and return loss greater than 10 dB. As a result, the filter is appropriate for 5G applications that use millimeter-wave RF front-end systems   &nbsp

Convertible Bandstop to Allpass Filter using Defected Ground Structure with Ideal Switch for Millimeter-Wave Band in 5G Application

According to this study, a defective ground structure (DGS) with an ideal switch can be used to create a bandstop to allpass filter for 5G applications. The redesigned Hairpin DGS's bandstop and allpass responses are mathematically investigated in this paper. Utilising an ideal switch via open circuit and short circuit conditions on DGS, the convertible filter is operated. Therefore, the filter's performance in terms of return loss, attenuation, and insertion loss is simulated. As a result, the filter operates at 25.875 GHz in open circuit condition with a narrowband (2.16 GHz) bandstop response at 10 dB and a maximum attenuation of 29.5 dB, and at 26 GHz with a wideband allpass response and return loss greater than 10 dB. As a result, the filter is appropriate for 5G applications that use millimeter-wave RF front-end systems   &nbsp

Metamaterial-Based Series-Fed Antenna with a High Gain and Wideband Performance for Millimeter-Wave Spectrum Applications

This paper presents a high-gain, wideband series-fed antenna designed for 5G millimeter-wave (MMW) applications. The structure employs a substrate-integrated-waveguide (SIW)-based power splitter and metamaterials (MMs). The power divider functions effectively at 27.5 GHz, exhibiting an impedance bandwidth from 26.9 to 28.6 GHz. The series-fed dipole is assembled on the SIW-based power splitter, incorporating four dipoles with varying lengths and spacing. The dipoles are connected in series on both sides, running in parallel through a microstrip line. Effectively combining the resonances of the series-fed dipoles and the SIW results in a broad impedance bandwidth, ranging from 26.9 GHz to 34.75 GHz. The design has a gain extending from 9 to 10.5 dBi within the operating bandwidth. To improve gain performance without a substantial increase in antenna size, 11 × 6 MM unit cells were positioned in front of the antenna. As a result, the proposed antenna achieves a maximum gain of 14.1 dBi at 30.5 GHz while maintaining an operational bandwidth of 7.85 GHz. Additionally, due to the arrangement of the two MM-based series-fed dipoles, the antenna exhibits symmetrical dual-beam E-plane radiation at ±20° and 28 GHz in the end-fire direction. The developed system was experimentally validated and an excellent agreement between the simulated and measured data was demonstrated

Design and Optimization of a Compact Super-Wideband MIMO Antenna with High Isolation and Gain for 5G Applications

This paper presents a super-wideband multiple-input multiple-output (SWB MIMO) antenna with low profile, low mutual coupling, high gain, and compact size for microwave and millimeter-wave (mm-wave) fifth-generation (5G) applications. A single antenna is a simple elliptical-square shape with a small physical size of 20 × 20 × 0.787 mm3. The combination of both square and elliptical shapes results in an exceptionally broad impedance bandwidth spanning from 3.4 to 70 GHz. Antenna dimensions are optimized using the trust-region algorithm to enhance its impedance bandwidth and maintain the gain within a predefined limit across the entire band. For that purpose, regularized merit function is defined, which permits to control both the single antenna reflection response and gain. Subsequently, the SWB MIMO system is constructed with four radiators arranged orthogonally. This arrangement results in high isolation, better than 20 dB, over a frequency band from 3.4 to 70 GHz band. Further, the system achieves an average gain of approximately 7 dB below 45 GHz and a maximum gain equal to 12 dB for 70 GHz. The system exhibits excellent diversity performance throughout the entire bandwidth, as evidenced by the low envelope correlation coefficient (ECC) (−3), total active reflection coefficient (TARC) (≤−10 dB), and channel capacity loss (CCL) (<0.3 bit/s/Hz) metrics, as well as the high diversity gain (DG) of approximately 10 dB. Experimental validation of the developed SWB MIMO demonstrates a good matching between the measurements and simulations

Planar antenna beam deflection using low‐loss metamaterial for future 5G applications

A method to tilt the beam of a planar antenna in the E-plane is demonstrated by implementing a metamaterial (MM) structure onto the antenna substrate at the fifth-generation (5G) band of 3.5 GHz. The beam tilting is achieved due to the phase change that occurs when the electromagnetic (EM) wave traverses through two media with different refractive indices. A new adjacent square-shaped resonator (ASSR) structure is proposed to achieve the beam tilting in a dipole antenna. This structure provides a very low loss of −0.2 dB at 3.17 GHz. The simulation and measurement results illustrate that the radiation beam of the dipole antenna is tilted by +25° and −24° depending on the position of the ASSR array onto the dipole antenna substrate. In addition, no degradation in the gain is observed as in the conventional beam-tilting methods; in fact, gain enhancement values of 3 dB (positive deflection) and 2.7 dB (negative deflection) are obtained compared with that of a dipole antenna with no ASSR array. The reflection coefficient of the dipole antenna with ASSR array has a good agreement with that of the dipole antenna with no ASSR array. The measured results agree well with the simulated ones

Refractive index reconfigurable metamaterial structure at 28 GHz frequency range

In this paper, a new refractive index reconfigurable metamaterial structure at millimeter wave (MMW) frequency range has been designed and simulated for beam switching in a future fifth-generation (5G) mobile network applications. The new proposed structure is composed of a Ladder shaped resonator (LSR) printed on the front face of a substrate layer and operates at 28 GHz. By proper arrangement of LSR unit cell, the proposed structure achieves a low loss and almost full transmission by -0.26 dB (0.97 in linear scale). To provide the refractive index reconfigurable feature, two PIN diodes are formed in the gaps of the structure. Thus, LSR can be switched between four states with a different refractive index values which are -60, -14, 0 and -12 at 28 GHz. In the simulation, the copper strip and measured S-parameters of the proposed PIN diode are used to achieve the reconfigurability. To demonstrate a reconfigurability of the new metamaterial structure, the return loss, insertion loss and real parts of the effective refractive index at each reconfigurable frequency are studies and investigated