Performance Of Antenna Array Research Articles

A side-edge frame dual-band eight-element MIMO antenna array for 5G handset

Abstract In this paper, a dual-band 8 × 8 multi-input multi-output (MIMO) array antenna operating in 3.5 GHz band (3400–3600 MHz) and 5.5 GHz band (5150–5925 MHz) for 5G mobile handset is presented. The proposed hybrid antenna includes a comb-shaped monopole and an L-shaped open slot antenna which are symmetrically located on the inner surface of the side-edge frame of smartphone. Pattern diversity is achieved that can mitigate envelope correlation coefficients (ECCs) and improve the MIMO system performances. The prototype of proposed dual-band eight-element MIMO antenna is fabricated and experimentally measured. The results show that isolation <−10 and <−15 dB, respectively in the lower band and high band without any additional decoupling element are achieved and the desired bands are satisfied under the condition of −6 dB impedance matching. Moreover, the essential parameters for evaluation of the MIMO system performance such as the ECC, mean effective gain (MEG), and ergodic channel capacity are calculated. Furthermore, the influence of user's hand on the radiation characteristics of proposed MIMO antenna are also investigated and discussed. Based on the result, the proposed MIMO antenna is a good candidate for use in future 5G applications.

A Compact Sequentially Rotated Circularly Polarized Dielectric Resonator Antenna Array

In this study, a compact 2 × 2 circularly polarized (CP) sequentially rotated (SR) dielectric resonator antenna (DRA) array operating in the IEEE 802.11a band is presented. To acquire the CP radiation, an elliptical slot (ES) was introduced to couple a rectangular dielectric resonator (RDR). The ES generates two resonant frequencies corresponding to the dominant even and odd modes. The SR feeder is made of four quarter-wavelength microstrip transformers to reduce the input impedance of the elements and, consequently, maximize the power transferred to each element. Experimental and simulation verifications were conducted on a 54 × 50 × 0.813 mm3 prototype to evaluate the performance of the proposed antenna array, which achieved a VSWR < −10 dB bandwidth of 1 GHz (5.1–6.05 GHz) and axial ratio (AR) < 3 dB of 0.95 GHz (5.1–5.85 GHz). The agreement between the simulated and measured results confirmed the validity of the proposed design.

Designing an 8-Shaped Slotted Array Antenna with 2x4 Configuration for Improved Ultra-Wideband Performance : A Simulation-based Approach

The article is about the design, simulation, and characterization of a 2x4 slotted microstrip patch antenna array that is optimized for operation in the S and C frequency bands. The antenna exhibits excellent performance with low reflection, good impedance matching, high gain, and low signal loss. The paper includes plots demonstrating the antenna's performance, indicating that it is suitable for a wide range of applications requiring high-performance antenna arrays. The research contributes to the development of slotted microstrip patch antenna arrays for ultra-wideband applications and highlights the importance of optimization in antenna design. Overall, the article provides valuable insights into the design and performance of antenna arrays, offering a useful reference for future research and development in this field.

Robust Adaptive Beamforming based on Automatic Variable Loading in Array Antenna

Diagonal loading technology is widely used in array antenna beamforming because of its simple method, low computational complexity and the ability to improve the robustness of beamformer. On this basis, this paper proposes a robust adaptive beamforming method based on automatic variable loading technology. The automatic variable loading matrix (AVLM) of the method is composed of two parts. The non-uniform loading matrix dominants when the input signal-to-noise ratio (SNR) is small, effectively control the influence of noise disturbance without affecting the ability of array antenna to suppress interference. The variable diagonal loading matrix dominants when the input SNR is high to improve the output performance of array antenna. Simulated results show that compared to other methods, the proposed method has better output performance for both low and high input SNR cases.

A Compensation Method for Active Phased Array Antennas: Using a strain-electromagnetic coupling model

Physical deformation due to service loads seriously degrades the electromagnetic performance of active phased array antennas. However, traditional displacement-based compensation methods are moderately difficult to use because displacement measurements generally require stable references, which are hard to realize for antennas in service. For deformed antennas, strain information is directly related to their displacement, and strain sensors can overcome carrier platform constraints to measure real-time strain without affecting the antenna radiation-field distribution. We thus present a compensation method based on strain information for in-service antennas. First, the minimum number of strain sensors is determined as the main modal-order-based modal effective mass fraction. According to the modal method and analysis of spatial phase-distribution errors related to strain, a coupled strain-electromagnetic model is established to evaluate antenna performance from the measured strain. The corresponding excitation phase from the measured strain is adjusted to compensate antenna performance. Finally, the method is experimentally validated using an X-band active phased array antenna under the influence of typical deformation conditions for both boresight and scanned beams. The results demonstrate that the presented method can effectively compensate for the performance of service antennas directly from the measured strain information.

Simulation of operation of dual-frequency antenna array of GLONASS consumer navigation equipment under influence of simulated interference

The article deals with the methods of increasing the noise immunity of the navigation equipment of the consumer under the influence of deliberate imitation interference (spoofing). The main differences between imitation interference and powerful noiselike interference are highlighted. The initial data for computer modeling of various signal-interference conditions are formed, with makes it possible to conduct a comparative analysis of various methods of interference suppression. The created model allows us to take into account the real coordinates of navigation satellites relative to the selected observation point, the geometry of the antenna array of the navigation receiver and its main functional characteristics. The possibility of using antenna arrays with a controlled diagram-forming scheme for focusing the radiation pattern in the directional of arrival of satellite navigation signals and creating a «zero» in the direction of arrival of interference is investigate. The dependence of the potential level of interference suppression on the elevation of interference arrival is analyzed. A comparison of two optimization methods used as an interference reduction algorithm is presented.

Methodical approach to estimation of energy characteristics of antenna arrays of space communication means of decimeter wavelengths

The article describes a sequence of mathematical and logical operations for determining the energy and mass-dimensional characteristics of an active phased array antenna operating in the decimeter wavelength range of space communications necessary to ensure continuous operation for a given time. When designing large-size antenna systems, a preliminary assessment of the mass-size, energy and thermal parameters is required to assess the feasibility of the project. In this regard, the article uses a mathematical apparatus that includes a model and methods that allow determining the tactical and technical characteristics of satellite communication systems at the design or development stage. The novelty of the developed method consists in assessing the potential capabilities of spacecraft of satellite communication and retransmission systems, taking into account the energy and weight and size characteristics of their antenna systems and in determining the degree of implementation of the main modes of operation of Earth stations at the design or development stage for the specified operating modes of satellite communication systems.

A UWB Antenna Array Integrated with Multimode Resonator Bandpass Filter

This paper presents a novel design of a modified ultrawideband (UWB) antenna array integrated with a multimode resonator bandpass filter. First, a single UWB antenna is modified and studied, using a P-shape radiated patch instead of a full elliptical patch, for wide impedance bandwidth and high realized gain. Then, a two-element UWB antenna array is developed based on this modified UWB antenna with an inter-element spacing of 0.35 λL, in which λL is the free space wavelength at the lower UWB band edge of 3.1 GHz, compared to 0.27 λL of a reference UWB antenna array designed using a traditional elliptical patch shape. The partial ground plane is designed with a trapezoidal angle to enhance matching throughout the UWB frequency range. The mutual coupling reduction of a modified UWB antenna array enhances the reflection coefficient, bandwidth, and realized gain, maintaining the same size of 1.08 λ0 × 1.08 λ0 × 0.035 λ0 at 6.5 GHz center frequency as that of the reference UWB antenna array. The UWB antenna array performance is investigated at different inter-element spacing distances between the radiated elements. To add filtering capability to the UWB antenna array and eliminate interference from the out-of-band frequencies, a multimode resonator (MMR) bandpass filter (BPF) is incorporated in the feedline while maintaining a compact size. The measurement results showed a close agreement with simulated results. The proposed UWB filtering antenna array design achieved a wide fractional bandwidth of more than 109.87%, a high realized gain of more than 7.4 dBi, and a compact size of 1.08 λ0 × 1.08 λ0 × 0.035 λ0 at 6.5 GHz center frequency. These advantages make the proposed antenna suitable for UWB applications such as indoor tracking, radar systems and positioning applications.

A Quad-Port Dual-Band MIMO Antenna Array for 5G Smartphone Applications

A quad-port antenna array operating in 3.5 GHz band (3.4–3.6 GHz) and 5 GHz band (4.8–5 GHz) for fifth-generation (5G) smartphone applications is presented in this paper. The single antenna element consists of an L-shaped strip, a parasitic rectangle strip, and a modified Z-shaped strip. To reserve space for 2G/3G/4G antennas, the quad-port antenna array is printed along the two long frames of the smartphone. The evolution design and the analysis of the optimal parameters of a single antenna element are derived to investigate the principle of the antenna. The prototype of the presented antenna is tested and the measured results agree well with the simulation. The measured total efficiency is better than 70% and the isolation is larger than 16.5 dB.

Wideband Octagonal Dual Circularly Polarized Sub-array Antenna for Ku-Satellite Systems

In this paper the analysis and design of a dual circularly polarized 4×4 antenna array operating in Ku-band are discussed with emphasis on its sequential feeding network. The dual circular polarization is achieved by feeding a stacked octagonal patches with a wideband branch line coupler. The proposed 4×4 antenna array is based on two separate sequential feeding networks for LH and RH circular polarizations. The advantage of the proposed feeding network is that it is implemented on a single layer. Simulation results by using both HFSS and CST are presented for comparison. In addition, experimental verifications are presented.

Numerical Analysis of an Applicator for Hyperthermia Treatment of Melanoma

This document presents the design and validation of an applicator conceived for hyperthermia treatment of the melanoma in the human male torso and female leg. The applicator consists of an antenna array operating in the 5.8GHz ISM band immersed in an interface layer. The resulting device is comfortable to wear by the patient, low-cost and easy to store and handle. Simulation is carried out using Sim4Life and the ViP 3.0 human model, and the results demonstrate correct energy delivery to the tissue under treatment.

Dual-Band Single-Layer Slot Array Antenna Fed by K/Ka-Band Dual-Mode Resonators in Gap Waveguide Technology

This letter presents a 4 × 4 single-layer dual-band array antenna operating in the K- and Ka-band using gap waveguide (GW) technology. Radiating elements consist of I-shaped slots located on the top plate of the antenna and backed by a novel coaxial cavity with the dual-frequency operation. The antenna presents two ports, one for each band, and radiates a directive far field pattern with linear polarization. A single-layer wideband corporate-feed network is used to excite the cavities. In addition, a diplexer is integrated as part of the network to separate both working bands. Experimental results show impedance and radiation pattern bandwidths larger than 2 GHz in both bands.

On Half-Power Beamwidth of Intelligent Reflecting Surface

Half-power beamwidth (HPBW) is a key parameter to measure the performance of antenna array and the newly proposed intelligent reflecting surface (IRS) systems. In this letter, we first establish a system model for IRS in uniform linear array (ULA) and uniform rectangular array (URA) configurations, then the IRS HPBW in both cases are derived under the far-field condition without considering channel path-loss and fading. We find that in ULA and URA configurations, IRS HPBW is equal to antenna array’s HPBW at the same reflect/transmit angle with maximal ratio combining applied, while IRS HPBW is always greater than or equal to antenna array’s HPBW when all weights are equal. Besides, under certain incident angles, there will be abrupt changes in HPBW and the analytical expressions of the boundary values in both ULA and URA cases are provided. Unlike the traditional active antenna array, our conclusion shows that the IRS HPBW will change with the incident angles. Simulation results verify the correctness of our derivations.

The effects of mutual coupling and polarization on the performance of steered-beam adaptive arrays

The polarization of the electromagnetic waves impinging on adaptive antenna arrays has a significant impact on their performance. The effects of desired and undesired polarized signals and mutual coupling on the performance of adaptive antenna arrays with an electronically steerable beam are studied based on the ratio of the output signal to the interference plus noise. The performance of adaptive antenna arrays composed of single- versus cross-dipole antenna elements is studied to illustrate the effect of signal polarization. The experimental and simulation results show that, for randomly polarized signals, adaptive antenna arrays using cross-dipole elements provide better performance compared with those using single dipoles. However, if the desired signal polarization is well known, single-dipole antenna arrays offer better performance.

Strawberry algorithm and its newly evolved variant for pattern nulling in an antenna array

In this article attempt has been made for the first time to apply the reported strawberry optimization technique to antenna array synthesis problem. The algorithm is further modified by reinforcing it with adaptive values for the two key parameters known as runner length and root length embedded in the mathematical expression governing the movement of the mother plant from one position to another in the search space to locate the optimum solution. The case studies cited here refer to linear and circular array configurations. The design constraints are limited to minimizing the side lobe level and restricting the first null beam width, which play significant roles in antenna array performances. The important features which greatly influence in achieving the said objectives are either placement of antenna elements or amplitudes of excitations of these elements or both. And the recently reported nature inspired metaheuristic optimization algorithms have addressed to these antenna problems quite effectively and the application of the strawberry algorithm for the first time and the unraveling of a new algorithm known as reduced step size strawberry algorithm (rss-SBA) a variant of the existing SBA have shown quite exciting results thus opening avenues for these techniques to be the potential contenders in the race of authenticating their positions in the domain of nonlinear function optimization.

Signal processing by adaptive antenna arrays

This article outlines the basic theory of adaptive antenna arrays. The basic elements of an adaptive antenna array such as a diagramforming device and an adaptive processor are presented. The task of the adaptive processor is to control the diagram forming device, which provides the required processing of the input observation based on the available a priori information on the signal-interference environment. When such information is insufficient, the adaptive processor must have the ability to automatically adjust to the receiving conditions. In other words, the adaptive processor must implement some adaptation algorithm based on the initial data bank and the signal processing efficiency criterion. To quantitatively evaluate the performance of adaptive antenna arrays when receiving a useful signal, one of the ways of quality indicator has been considered: the RMS value of the deviation of the useful signal from the reference.

Mutual Coupling Effect in Unequally - Spaced Linear Antenna Array Performance

Unequally-spaced arrays can offer some advantages over equally-spaced arrays as follows: reducing the side-lobed level for the broadband array with an identical excitation coefficient. However, array design techniques do not take into account the mutual coupling effect among elements. In this article, the effect of mutual coupling on the array radiation pattern is investigated and discussed through studying the input impedance of the elements. Next, a technique for reducingmutual coupling based on radiation patterns of elements is presented. In this technique, the log-periodic dipole antenna with a frequency ranging from 900 MHz to 2500 MHz is selected as an array element. The results based on the FEKO magnetic field calculation program have shown that at 900 MHz, the proposed antenna array reaches a side-lobed level of -17.4 dB. At frequencies of 1500 MHz, 2000 MHz, 2500 MHz, the grating lobe levels of this antenna array are lower than 6.7 dB, 9.5 dBand 8.3 dB compared to those of the equally - spaced antenna array.

Performance Enhancement of 5G Millimeter Wave Antenna Module Integrated Tablet Device

This article describes the design and considerations for millimeter-wave (mmWave) 5G antenna modules embedded in a tablet device. The antenna module consists of eight-chain broadside antenna array and two pairs of four-chain endfire antenna array. A dual-polarized air-filled stacked patch antenna is designed for the broadside patch antenna. Although the performance can be deteriorated due to a plastic cover, the proposed antenna enables an adaptable design for a dielectric cover. A novel surface-mountable chip antenna is also proposed, to implement a vertical polarized (V-pol.) endfire antenna on a low-profile substrate. To integrate a dual-polarized endfire antenna in a confined space, a horizontal polarized (H-pol.) mesh grid antenna and a V-pol. chip antenna are collinearly integrated. In addition, a plastic cover on the tablet is modified to enhance the performance of the endfire antenna array. The cumulative distribution function (cdf) of effective isotropic radiated power (EIRP) is utilized to evaluate spherical coverage, based on the 5G standard of 3rd Generation Partnership Project (3GPP). The spherical coverages are presented by varying the types of plastic cover, the effects of the blockage, and the number of mmWave 5G modules.

A compact folded SIW multibeam antenna array for 5G millimeter wave applications

AbstractA novel compact multilayer multibeam antenna array based on substrate integrated waveguide (SIW) is proposed in this letter for 5G millimeter wave (mm‐wave) applications. A multimode beam forming network (BFN) cascaded by phase compensation and coupling structures is folded to make the antenna array more compact. The phase difference between the output ports of traditional multimode beamforming network is very unstable, which would seriously affect the multibeam performance of antenna array. Therefore, the compensating phase shifter adopts the SIW transmission line structure with unequal length and width, which enables the multimode BFN achieving better performance in the bandwidth of 27–29 GHz. Four slot arrays are employed as the radiation structure. The overall structure of the proposed antenna consists of three parts, including a multimode beamforming network, a compensated phase shifter, and an SIW slot array. If these components are cascaded directly, the size of the antenna would be very large and the aperture efficiency will be low. So the proposed antenna is folded into three layers, one part for each layer. The overall antenna size is 66.7 mm × 47.5 mm (6.23λ × 4.44λ at 28 GHz). The antenna array is designed, fabricated, and measured. The measured results show that four deflected beams are realized in the band of 27–29 GHz. The radiation beams demonstrate a wide azimuthal coverage of ±48 deg, and a peak gain of 16.8 dBi for Port 1 excitation and 17.3 dBi for Port 2 excitation. The simulated radiation efficiency is better than –2 dB from 27 to 29 GHz. The proposed antenna features a compact size, low profile, good radiation performance, which is well suited for applications in the 5G mm‐wave communication systems.

Heatsink Antenna Array for Millimeter-Wave Applications

In this communication, a novel fin-shaped heatsink antenna array is designed and fabricated by 3-D printing and low-temperature cofired ceramic (LTCC) technologies. Its structure consists of 16 rectangular air cavities in the bottom base, which are used to form the open-ended rectangular waveguide antennas. Combined with the waveguide and metallic fins, a step-profiled horn is formed as the antenna element, which further enhances the radiation performance. This heatsink antenna array is soldered on an LTCC substrate and the feeding network is realized by the substrate integrated waveguides (SIWs) with numerous metallic vias. These metallic vias inherently provide an effective path for transferring the heat from chips to the heatsink. The simulated performance of this heatsink antenna array is in good agreement with the measured one. The measured broadside gain is 18.1 dBi at 60 GHz, and the 10 dB relative impedance bandwidth is 11.7%.