Designed Antenna Element Research Articles

An elliptical dual-band antenna with crescent slot for 5G mmWave applications

Abstract This paper proposes a new elliptical dual-band antenna with a crescent slot with the advantages of compactness, lightweightness, low cost, and easy installation for 5G mmWave applications. The radiating element is obtained by Boolean manipulation of three ellipses of unequal length to short axis ratio, the resulting crescent slot defining its dual-band characteristics. The -10 dB impedance bandwidth of 23.8—31.6 GHz at 28 GHz and a bandwidth range of 36.8—40.6 GHz at 38 GHz are achieved, completely covering the currently applicable n257, n258, n260 and n261 mmWave bands and filtering out the unlicensed 31—36 GHz band. Dimensions of the single element are 10 mm by 7 mm. In addition, to reduce the interference caused by atmospheric attenuation, a conventional feeder network is combined with the designed antenna element to form a 1 × 4 line array to improve the gain. The antenna array with total dimensions of 20 × 25 mm2 is modeled in 0.254 mm thick Rogers 5880 substrate. As a result of the array configuration, 10.4 dBi gain and a 95% radiation efficiency are achieved in the 28 GHz band. Meanwhile, at the 38GHz band, the gain is 10.4 dBi and the radiation efficiency is 95%. The proposed antenna meets the 5G communication requirements well and can be a better candidate in the mmWave band range.

Broadband Quad-Element MIMO Antenna with Enhanced Isolation for Sub-6 GHz and Sub-7 GHz 5G Applications

In this manuscript, a broadband quad-element MIMO antenna with enhanced isolation for n77, n78, and n79 bands of Sub-6 GHz and the n46 and n96 bands of Sub-7 GHz under 5G applications is designed. The designed antenna element is a rectangular monopole antenna comprising a semi-circular cut and a semi-circle embedded to obtain a wide bandwidth. These four-element antennas are aligned orthogonally to achieve the compact size and high isolation features of MIMO performance. The overall area of MIMO antenna is 40×40x1.6 mm3. MIMO antenna has a high isolation of <- 21 dB, an envelope correlation coefficient (ECC<0.002), a high diversity gain (DG> 9.99), an MEG gain of -3 dB, and a peak gain of 5.08 dBi.The results of the experiment are satisfactory with the S-parameter simulation results According to the results, a broadband quad-element MIMO antenna is a suitable candidate for Sub-6 GHz and Sub-7 GHz 5G applications.

Design and characterization of a minimized planar dual‐band MIMO circular ring antenna with high efficiency

AbstractA minimized planar dual‐band multiple‐input multiple‐output antenna with high efficiency for the fifth‐generation applications is proposed in this paper. The designed antenna is composed of two identical radiating elements and a defected ground structure (DGS). Each radiating element is made up of a circular ring, a U‐shaped microstrip, a T‐shaped microstrip, and an L‐shaped microstrip. A rectangular microstrip with a small square stub is connected to the DGS to improve the isolation. The size of the designed antenna element is 24 mm × 15 mm. The measured reflection coefficients are less than ∗10 dB in the 5G New Radio n77/n78/n79 (3.3–4.2 and 4.8–4.96 GHz). The total peak gain and efficiency are greater than 3.5 dBi and 82%, respectively. The values of calculated envelope correlation coefficient are lower than 0.015. The proposed dual‐band MIMO antenna is suitable for 5 G applications.

Circular Polarization-Agile and Continuous Beam-Steerable Array Antenna Using a Hybrid Design Approach

A circular polarization (CP)-agile and continuous beam-steerable array antenna is presented using a hybrid design approach. It is accomplished by combining digital reconfigurable antenna elements with analog continuously tunable phase shifters. To realize both polarization reconfiguration and initial phase generation for beam-scanning simultaneously, the designed antenna element enables eight states that corresponds to two CP modes with four quantized phases. The phase shifters further provide additional variable phases of -90° to 0° for antenna element excitation. Superposition of the initial and additional phases helps to satisfy a full and continuous 360° phase coverage for a beam-steerable array. Meanwhile, the phase decomposition also facilitates the design of phase shifters without complex or cascaded structures. By altering the bias states of the electronic components loaded in the array antenna, CP switching and beam scanning can be independently controlled. For verification, prototypes of the antenna element, phase shifter, and a four-element array are all fabricated and tested. Reasonable agreement is obtained between simulation and measurement. The resultant array could scan up to nearly ±40° off the boresight, along with stable radiation patterns and good CP performance.

A Frequency Reconfigurable Compact Planar Inverted-F Antenna for Portable Devices

In this paper, a low-profile, compact size, inexpensive, and easily integrable frequency reconfigurable antenna system is proposed. The proposed antenna consists of an inverted-F shape antenna, capacitors, and switching PIN diodes. The designed antenna element is fabricated on easy available and less expensive FR-4 substrate ( ε r = 4.4, tan δ = 0.02). The switching diodes are incorporated within the radiating structure of the antenna design, and by changing the different states of PIN diodes, frequency reconfigurable response is achieved. While adjusting the different states of the diodes, the antenna resonates between 0.841 GHz and 2.12 GHz and covers six different frequency bands. The proposed system has compact size of 44 × 14 × 3.2 mm 3 . The gain of the antenna is between 1.89 and 2.12 dBi. The measurement results shows the good agreement with simulated results for different key performance parameters. Additionally, the proposed antenna shows omni-directional far-field characteristics for various different frequencies.

Isolation enhancement of metamaterial structure MIMO antenna for WiMAX/WLAN/ITU band applications

AbstractThe μ-negative metamaterial (MNG) two-element MIMO antenna design was proposed in this article for WiMAX (2.5–2.8 GHz), WLAN (3.2–5.9 GHz), and ITU band (8.15−8.25 GHz) applications. The first design of the MIMO antenna operates at 2.7 and 4.9 GHz frequencies. In order to reduce the mutual coupling, a defective ground structure is used. For further isolation improvement, an MNG unit cell is placed in between the two radiating elements at a distance of 10 mm. The designed antenna elements have better than −23 dB coupling isolation between the two radiating elements. Moreover, with MNG an additional frequency of 8.2 GHz is obtained, which is useful for ITU band applications. The proposed antenna bandwidth is expanded by 19% in the lower operational band, 20% in the second operational band, and 32% in the higher frequency band with the MNG unit cell. From the analysis, the proposed antenna is suitable for WiMAX/WLAN/ITU band applications because of its low enveloped correlation coefficient, and highest directive gain and low mutual coupling between the radiating components. The proposed antenna was simulated, fabricated, and measured with the help of the Schwarz ZVL vector network analyzer and anechoic chamber. Both measured and simulated results are highly accurate and highly recommended for WiMAX/WLAN/ITU bands.

THz CMOS On-Chip Antenna Array Using Defected Ground Structure

In this paper, we design a THz CMOS on-chip patch antenna with defected ground structure (DGS) and utilize it to implement a broadband and high gain on-chip antenna array. It is verified from the simulation that the DGS not only can increase the gain and bandwidth of the antenna element, but also can increase the isolation between the antenna elements in the on-chip array. Therefore, it allows the design of the compact 1 × 2 and 2 × 2 on-chip antenna array with high gain and broad bandwidth. The element spacing and feedline structures of the antenna array are designed and optimized by the simulations. The designed antenna element, and 1 × 2 and 2 × 2 antenna arrays are fabricated in a commercial 65 nm CMOS process. In the on-wafer measurement, they exhibit an antenna gain of 3.1 dBi, 7.2 dBi, and 8.2 dBi with a bandwidth of 14.0%, 21.3%, and 28.0% for the reflection coefficient less than −10 dB, respectively, at 300 GHz. This result corresponds to very good performance compared to the reported THz CMOS on-chip antenna array. Therefore, the designed CMOS on-chip antenna element and array using DGS in this work can be effectively applied to build low-cost and high performance THz systems, because they can be fully implemented in a conventional CMOS process without requiring any additional processes or manufacturing techniques.

A Complete System of Wireless Power Transfer Using a Circularly Polarized Retrodirective Array

A complete system of wireless power transfer using a circularly polarized retrodirective array is presented. A dual frequency, active retrodirective array is proposed for a transmitter system. The antenna array uses circularly polarized microstrip patch antenna subarrays with sequential rotation and surface wave suppression. The designed antenna element eliminates undesired coupling between array elements due to surface waves present in conventional microstrip antenna arrays in order to improve array performance. A sequential rotation technique was implemented to improve impedance matching and circular polarization bandwidths. The proposed retrodirective array was designed to operate at about 2.4 GHz for the interrogating signal and about 5.8 GHz for the retransmitted signal. The beam scanning inherent in retrodirective arrays ensures a uniform power level available to the receiving devices, regardless of their location within the angular sector over which retrodirectivity is achieved. A rectenna was designed as a receiver in order to have a complete system the wireless power transfer. A zero bias Schottky diode with high detection sensitivity was used as the rectifying device. The shorting pins used in the antennas to suppress surface waves also act as return paths for the DC current, eliminating the need for an RF chock in the rectifier circuit. The design procedure, simulation results, and experimental measurements are presented.

Synthesis of multi‐polarised upside conical frustum array antenna for 5G mm‐Wave base station at 28/38 GHz

In this study, a multi-polarised millimetre-wave (mm-Wave) base station operating at 28/38 GHz is introduced for future fifth generation (5G) mobile communication networks. The proposed station employs 32-element array antenna distributed in upside conical frustum configuration (UCFC) to synthesise multi-beam patterns adopting directivity and polarisation control. First, the design of dual-band circularly polarised antenna element at 28/38 GHz is discussed. The measured results show that the designed antenna element has a reflection coefficient less than -23 dB with a realised antenna gain of 8 dBi, on average, in the assigned frequency bands. Based on the designed antenna element, the antenna array performance is studied in terms of gain, radiation efficiency, reflection coefficient, and coverage efficiency. The results are compared with those obtained from 32-element structured in an octagonal prism configuration (OPC). For antenna design parameters and multi-beam pattern synthesis, a modified version of hybrid gravitational search algorithm and particle swarm optimisation is proposed. It is found that, the introduced UCFC outperformed the OPC by 19.8%. Moreover, distributing the antenna array in UCFC improved the convergence by 21.7% compared to OPC.

Quasi‐fractal antenna system based on asymmetric TEM‐horns nested into each other

AbstractIn this article was studied a way to minimize the overall dimensions of a multiband antenna system operating in a number of ultra‐wideband frequency bands using the quasi‐fractal construction principle. The results of an experimental study of the designed antenna element, which is a set of asymmetrical self‐similar TEM‐rupors nested into each other, are presented.

Performance of Tri-Band Multi-Polarized Array Antenna for 5G Mobile Base Station Adopting Polarization and Directivity Control

In this paper, the performance of tri-band multi-polarized adaptive array antenna for 5G mobile base station is introduced adopting the polarization and directivity control. First, the design of multi-band circularly polarized antenna element at 28/38/48 GHz is presented. The measured results show that the designed antenna element has a reflection coefficient of less than −20 dB in the assigned frequency bands of 28/38/48 GHz with a realized antenna gain of 7.82 dB, 8.39 dB, and 7.73 dB, respectively. Based on the designed antenna element, a 32-element are distributed in an octagonal prism configuration is presented as possible candidates for the future 5G mmWave cellular networks. The antenna array performance is studied in terms of gain, radiation efficiency, return loss, and axial ratio for different scenarios, in addition, the metrics of total scan pattern and coverage efficiency are investigated. To optimize the antenna parameters and synthesizing multi-beam patterns, a modified version of hybrid gravitational search algorithm and particle swarm optimization algorithm is introduced. This enhancement has improved the global search ability and accelerates the convergence capability. The proposed array antenna achieved good S11 < −20 dB with high isolation between the array elements. Besides, an acceptable realized gain of 16.85 dB on average with a radiation efficiency of more than 82 % is obtained in the entire operation bands.

Design of dual‐band circularly polarised array antenna package for 5G mobile terminals with beam‐steering capabilities

Here, a new design of phased-array antenna for future fifth-generation mobile phone applications is presented. The proposed phased array consists of 12 dual-band circularly polarised antenna elements at 28/38 GHz used to form a linear array in the edges region (top-side, right, and left sides) on a mobile phone circuit board. The measured and simulated results show that the designed antenna element has a reflection coefficient less than -15 dB in the assigned frequency bands of 28/38 GHz with a realised antenna gain of 7.68 and 7.73 dB, respectively. Furthermore, the performance of the array antenna package in the vicinity of user's head-hand has been investigated in this study at different scenarios. The designed array antenna achieved good matching impedance with high isolation between the array elements. Moreover, an acceptable realised gain of 16.85 dB on average with an axial ratio <;3 dB is obtained in the entire operation bands. Lastly, the metrics of total scan pattern, coverage efficiency, and user shadowing are investigated. It is found that the proposed phased-array antenna has good 3D beam-steering characteristics, which makes it suitable for millimetre-wave 5G mobile applications.

Design of a compact mimo antenna with asymmetric coplanar strip‐fed for UWB applications

ABSTRACTThis article presents a new compact asymmetric coplanar strip ‐fed UWB MIMO antenna. The UWB MIMO antenna consists of two identical elements which have quarter elliptical ring radiating element with asymmetric coplanar strip‐fed. By designing the antenna using asymmetric coplanar strip‐fed, the antenna size can be reduced (its size is only 6 × 2.6 cm2). The distance between the two antenna elements equals 0.37 λ0‐The single antenna element is operated at frequencies from 3.1 GHz to 10.6 GHz with reflection coefficient lower than −10 dB. In addition, the designed antenna elements have less than 15 dB coupling isolation between the two input ports. The diversity performance between two antenna elements such as envelope correlation coefficient and diversity gain are investigated and they are within their allowed limits. This analysis confirms that the designed antenna is suitable for portable UWB MIMO applications. The proposed antenna is designed; simulated and measured. There is a good agreement between the simulated and measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:31–36, 2017

CRLH MIMO antenna with reversal configuration

A design of CRLH MIMO metamaterial with reversal CRLH configuration antenna is presented. The two antenna elements are designed to operate at 5.8GHz for wireless applications. The two antenna elements are designed using reversed one left handed unit cell for high mutual coupling isolation in close separation. The two elements of MIMO antenna are put together with very small separation between them where the distance between the edges of two antenna elements is only 0.034 λ0. The MIMO antenna has compact size (its size is only 2.93×2.6cm2). The designed antenna elements have better than 35dB coupling isolation between the two inputs without using extra structures. The performance of MIMO antennas is evaluated by studying the correlation coefficient, diversity gain and total active reflection coefficient. A good agreement is achieved between simulation and measured results.

Generation of OAM Radio Waves Using Patch Antenna

This paper introduces a feasible patch antenna to generate OAM-carrying radio beams. Eight identical printed dipole antennas with microstrip balun feedline are arranged in an octahedron cylindrical substrate. Every printed dipole is fed with unit amplitude but with a successive phase difference from element to element. We can change the phase difference at the steps of 0, ±45o, ±90o, and ±135o to obtain mode numbers 0, ±1, ±2, and ±3. Simulation shows that the OAM states of ±1, ±2 and-3 achieve the expected results well, while the state of +3 produce a deviation due to the radiation difference of the designed antenna element and traditional tripole antenna. Furthermore, we achieve the impedance matching of every port and increase the directivity of the antenna. Thus, the proposed antenna is a promising candidate to generate OAM in engineering.

Compact and Closely Spaced Metamaterial MIMO Antenna With High Isolation for Wireless Applications

This letter presents a design of a two-element multiple-input-multiple-output (MIMO) metamaterial-based antenna. The two antenna elements operate at 5.8 GHz for wireless applications. The two antenna elements are designed employing only one left-handed unit cell. The reduction of mutual coupling between the two antenna elements is achieved by using a simple defected ground structure between them to limit the surface waves between them. The distance between the two antenna elements is only 1.8 mm (0.034 λ0). The designed antenna elements have better than -45 dB coupling isolation between the two inputs. Moreover, the proposed MIMO antenna has the advantage of compactness (its size is only 2.36 × 2.6 cm2). The design represents size reduction of more than 50% compared to conventional patch antennas operating at the same frequency. The proposed MIMO system has -55 dB correlation coefficient between its two elements.

Broadband low-cost planar sector antenna element for WLAN applications

A novel planar antenna element for applications in sector antennas is proposed. The antenna element consists of three patches coupled both electromagnetically and through the feeding network to ensure 90°beamwidth in a wide frequency range. A suspended microstrip technique has been used to ensure simultaneously low production costs and low losses within the feeding network. The designed antenna element operates within a frequency range of 5.1-5.9 GHz.

Formulas for the computation of the physical properties of rectangular microstrip antenna elements with various substrate thicknesses

Formulas available in the literature for the design of the physical properties of rectangular microstrip antenna elements are discussed, and their validity is assessed. Their variations have been experimentally examined by analyzing a set of newly designed antenna elements with substrates satisfying the criterion h ≤ 0.0815λ0 for 2.22 ≤ ϵr ≤ 10.2, where λ0 is the free-space wavelength, h is the thickness, and ϵr is the relative permittivity of the dielectric substrate. New formulas that can determine the antenna physical properties and the effective dielectric constant are empirically determined. ©1996 John Wiley & Sons, Inc.

Formulas for the computation of the physical properties of rectangular microstrip antenna elements with various substrate thicknesses

Formulas available in the literature for the design of the physical properties of rectangular microstrip antenna elements are discussed, and their validity is assessed. Their variations have been experimentally examined by analyzing a set of newly designed antenna elements with substrates satisfying the criterion h ≤ 0.0815λ0 for 2.22 ≤ ϵr ≤ 10.2, where λ0 is the free-space wavelength, h is the thickness, and ϵr is the relative permittivity of the dielectric substrate. New formulas that can determine the antenna physical properties and the effective dielectric constant are empirically determined. ©1996 John Wiley & Sons, Inc.

The resonant frequency of rectangular microstrip antenna elements with various substrate thicknesses

Formulas based on transmission-line, cavity, and magnetic-wall models to determine the resonant frequencies of a rectangular microstrip antenna element have been studied and their validity assessed. Their variations were experimentally verified by analyzing a set of newly designed antenna elements with substrates satisfying the criteria h ≤ 0.0815λ0 for 2.22 ≤ ϵr ≤ 10.2, where λ0 is the free-space wavelength, h the thickness, and ϵr the relative permittivity of the dielectric substrate. © 1996 John Wiley & Sons, Inc.