Gain Of Antenna Array Research Articles

Miniaturized array antenna base on metamaterial structures

A high gain array antenna consisted of 16 SRR elements is presented in this paper. Each element is comprised of two square rings located into the 16 SRR elements parallelly fed by power divider. The offered array antenna with high sensitivity to frequency band variation is suitable for wireless communication systems including 2.4 GHz and 5.2 GHz. Due to the high matching for input, power divider and elements the proposed system has a high gain of about 7.5 dB in the resonance frequencies. On the other hand, circular polarization can be obtained by utilizing ring structures. The simple and compact antenna with overall size of 32 × 40 mm2 is simulated and tested on a FR-4 substrate with 0.8 mm thickness. Acceptable agreement can be seen for the simulation and experimental results.

Three-dimensional aperture principle for end-fire radiation antenna array

According to the two-dimensional aperture principle, directivity and gain are expected to be proportional to the aperture area of an antenna or antenna array. Our simulations and measurements of an end-fire radiation antenna array overturn this conventional wisdom. The gain of an end-fire antenna array is found to be much higher than that calculated by the two-dimensional aperture principle. We introduce a length component into the two-dimensional aperture principle and propose a three-dimensional aperture principle. A four-element end-fire antenna array is designed and measured to verify the correctness of this new principle. The three-dimensional aperture principle opens a pathway to novel types of aperture utilization.

Microwave Wireless Power Transfer System Based on a Frequency Reconfigurable Microstrip Patch Antenna Array

The microwave wireless power transfer (MWPT) technology has found a variety of applications in consumer electronics, medical implants and sensor networks. Here, instead of a magnetic resonant coupling wireless power transfer (MRCWPT) system, a novel MWPT system based on a frequency reconfigurable (covering the S-band and C-band) microstrip patch antenna array is proposed for the first time. By switching the bias voltage-dependent capacitance value of the varactor diode between the larger main microstrip patch and the smaller side microstrip patch, the working frequency band of the MWPT system can be switched between the S-band and the C-band. Specifically, the operated frequencies of the antenna array vary continuously within a wide range from 3.41 to 3.96 GHz and 5.7 to 6.3 GHz. For the adjustable range of frequencies, the return loss of the antenna array is less than −15 dB at the resonant frequency. The gain of the frequency reconfigurable antenna array is above 6 dBi at different working frequencies. Simulation results verified by experimental results have shown that power transfer efficiency (PTE) of the MWPT system stays above 20% at different frequencies. Also, when the antenna array works at the resonant frequency of 3.64 GHz, the PTE of the MWPT system is 25%, 20.5%, and 10.3% at the distances of 20 mm, 40 mm, and 80 mm, respectively. The MWPT system can be used to power the receiver at different frequencies, which has great application prospects and market demand opportunities.

Evaluation of Interference in Ultra-Dense 5G Radio Access Networks with Beamforming

In this paper, we investigate the dependence of the level of intersystem interference
 on the beam width of the adaptively formed antenna radiation pattern and the territorial separation of neighboring devices in ultra-dense 5G radio access networks. The results of simulation modeling of a radio access network based on 19 base stations with the parameterization of the antenna array gain by the width of the radiation pattern in the horizontal plane show that when the base station beam is di-rected to the user device and narrowed from 360° to 5°, the level of intrasystem interference decreases by 15 dB compared with the case of omnidirectional antennas. The results of simulation
 of a radio access network based on 19 three-sector base stations with planar antenna arrays
 of 64 elements illustrate a significant reduction in the level of interference in comparison with the case of omnidirectional antennas and, in order to obtain zones of a positive signal-to-noise ratio, confirm the need for a territorial separation of neighboring devices by 10–20 % of the range of radio coverage.

Ray-Tracing-Based Numerical Assessment of the Spatiotemporal Duty Cycle of 5G Massive MIMO in an Outdoor Urban Environment

In the near future, wireless coverage will be provided by the base stations equipped with dynamically-controlled massive phased antenna arrays that direct the transmission towards the user. This contribution describes a computational method to estimate realistic maximum power levels produced by such base stations, in terms of the time-averaged normalized antenna array gain. The Ray-Tracing method is used to simulate the electromagnetic field (EMF) propagation in an urban outdoor macro-cell environment model. The model geometry entities are generated stochastically, which allowed generalization of the results through statistical analysis. Multiple modes of the base station operation are compared: from LTE multi-user codebook beamforming to the more advanced Maximum Ratio and Zero-Forcing precoding schemes foreseen to be implemented in the massive Multiple-Input Multiple-Output (MIMO) communication protocols. The influence of the antenna array size, from 4 up to 100 elements, in a square planar arrangement is studied. For a 64-element array, the 95th percentile of the maximum time-averaged array gain amounts to around 20% of the theoretical maximum, using the Maximum Ratio precoding with 5 simultaneously connected users, assuming a 10 s connection duration per user. Connection between the average array gain and actual EMF levels in the environment is drawn and its implications on the human exposure in the next generation networks are discussed.

Dynamic Resource Allocation in UAV-Enabled mmWave Communication Networks

Unmanned aerial vehicle (UAV)-enabled cellular architecture over the millimeter-wave (mmWave) frequency band is likely to be the best solution for on-demand high data rate service provisioning in the next generation communication networks. The beam formed by the mmWave antenna array is highly directional and requires multiple-beam scans to cover the entire area. This work presents a novel sectoring approach to ensure coverage of the whole area. The side lobe gain of the antenna array is taken into consideration, which generates substantial interference in other sectors. The expression for the probability distribution of the signal-to-interference-plus-noise ratio due to simultaneous transmissions in different sectors is derived in the downlink communication scenario. To limit interference in the concurrent transmission strategy, a threshold on power spillage from adjacent sectors is placed. For this topology, a resource allocation problem is formulated aiming to maximize the sum rate while ensuring a minimum rate guarantee to each user. It is observed that sum-rate variation with height is unimodal. The sum power and backhaul capacity constraints are accounted. This optimization problem is mixed-integer nonconvex programming. Hence, it is solved using the Lagrangian dual decomposition method, which provides an asymptotic global optimal solution. Since this method is computationally intensive, a suboptimal solution is proposed. Simulation results demonstrate convergence to an optimal solution, and it is observed that backhaul link capacity restricts the sum rate. Numerical results are presented for multiple representative field environments consisting of different types of built-up areas. It is observed that the transmitter antenna array sidelobe has a strong impact on the performance as compared to the ideal scenario without sidelobe, which overestimates the total sum rate by a factor of 3.

Spectral Efficiency Augmentation in Uplink Massive MIMO Systems by Increasing Transmit Power and Uniform Linear Array Gain.

Improved Spectral Efficiency (SE) is a prominent feature of Massive Multiple-Input and Multiple-Output systems. These systems are prepared with antenna clusters at receiver and transmitter . In this paper, we examined a massive MIMO system to increase SE in each cell that ultimately improves the area throughput of the system. We are aiming to find appropriate values of average cell-density (D), available bandwidth (B), and SE to maximize area throughput because it is the function of these parameters. Likewise, a SE augmentation model was developed to attain an increased transmit power and antenna array gain. The proposed model also considers the inter-user interference from neighboring cells along with incident angles of desired and interfering users. Moreover, simulation results validate the proposed model that is implementable in real-time scenarios by realizing maximum SE of 12.79 bits/s/Hz in Line of Sight (LoS) and 12.69 bits/s/Hz in Non-Line of Sight (NLoS) scenarios, respectively. The proposed results also substantiate the SE augmentation because it is a linear function of transmit power and array gain while using the Uniform Linear Array (ULA) configuration. The findings of this work ensure the efficient transmission of information in future networks.

Development of 60-GHz millimeter wave, electromagnetic bandgap ground planes for multiple-input multiple-output antenna applications

For 60-GHz band communications, both the mutual coupling and transmission distance restrict the performance of a multiple-input multiple-output (MIMO) antenna array. Several studies presented different types of meta-materials and electromagnetic bandgap (EBG) structures to improve the performance of a MIMO antenna array at the 60-GHz band. In this paper, we presented the four-element MIMO patch antenna with different types of EBG structures for the millimeter wave (mmW)communications at the 60-GHz unlicensed industrial, scientific, and medical band. The single element of the MIMO antenna array covered the mmW band from 57 GHz to 63 GHz having the dimensions of 1.3 mm × 1.8 mm × 0.1 mm. We developed a set of square-shaped, cross-shaped, and complex-slotted EBG ground planes between the antenna elements for the performance improvement. All the three EBG ground planes provided significant coupling reduction between the mmW MIMO antenna elements. The proposed EBG structures exhibited wide bandgap characteristics and improved scattering parameters in the desired frequency band. In contrast with the cross- and complex-slotted, the square-shaped EBG structure substantially improved the overall gain of MIMO antenna array. In addition, the square-shaped EBG reformed the maximum beam and enhanced the far-field gain pattern in the desired direction. Experimental results conducted with the fabricated prototypes showed a good agreement with the simulation results and adequately covered the 60-GHz band. The low-profile and salient features of the proposed MIMO antenna array shows the potential for on-chip applications at 60 GHz.

Circularly polarized microstrip Yagi antenna array with tilted beam for improved monopulse characteristics

AbstractAn antenna array composed of four inclined microstrip Yagi antennas is proposed for a direction finding (DF) system operated in L band. Each element antenna is designed to have a tilted beam toward a central array axis in order to have high gain in the boresight axis of the antenna array. In comparison to a patch antenna array, having the same structure, antenna array gain is improved by a 2.3 dB maximum around the array axis, monopulse slope is increased by 72% and the linearity of the slope is improved significantly. Also, axial ratio is improved by 3 dB max within ±25° from boresight.

Beamspace MIMO-NOMA for Millimeter-Wave Broadcasting via Full-Duplex D2D Communications

In order to meet the tremendous requirements on the convergence between broadband and broadcast, this paper proposes to incorporate layered division multiplexing (LDM), an important variant of non-orthogonal multiple access (NOMA) technologies, into Millimeter wave (mmWave) multiple-input multiple-output (MIMO) system with device-to-device (D2D) communications to simultaneously provide broadcast and unicast services. The performance of the proposed full-duplex D2D-aided mmWave MIMO-NOMA with randomly deployed users is then analyzed under practical assumptions. Closed-form expressions of both the outage probability and the ergodic capacity are then derived by using the Laplace transform technique. Finally, detailed numerical results reveal the performance gains of the proposed scheme compared with the LDM without D2D communications and conventional time division multiplexing based scheme. The impacts of the antenna array gain and the transmission power of both the base station and the full-duplex link on system performance are also presented. Besides, we observe that it is vital to optimal the transmission power of the full-duplex link which ensures less self-interference to enhance the system capacity.

Adaptive Spoofing Suppression Algorithm for GNSS Based on Multiple Antennas Array.

The signals of navigation satellites are easily affected by spoofing interference, causing the wrong position, speed or Universal Time Coordinate of the receiver to be calculated. Traditional detection and suppression algorithms are used only to eliminate the spoofing signals, which may lead to an insufficient number of satellites for positioning. An adaptive spoofing suppression algorithm (ASSA) based on a multiple antenna array is proposed in this study. The ASSA can use the cross-correlation gain of multiple antenna array to adaptively generate nulling and realize the simultaneous suppression of multiple spoofing signals. Moreover, ASSA does not need to capture and track spoofing separately, thus reducing the complexity of implementation and calculation. Experiments were conducted to verify the proposed system under different conditions, and the results show that ASSA can suppress multiple spoofings with little impact on positioning performance. Under the condition of spoofing, ASSAs were (2.22 m, 2.41 m, 4.43 m) in the static test and (2.27 m, 2.43 m, 4.64 m) in the kinematic test, which are good positioning performances for both. In addition, the ASSA is applied before capturing signals, which is beneficial to identifying and eliminating spoofing earlier and faster.

Jedno rešenje simulatora izahorizontskog radara

Introduction/purpose: The OTHR simulator presented in this paper is developed and used in practice, with the aim of emulating radar signal environment, but also optimizing the radar parameters in real applications such as: radiated power, antenna array gain, path loss, radar cross section, external interference, and noises. Methods: In this paper, the methodology of mathematical modeling is used as well as simulations . Results: Based on the performed analysis, the output data from the OTHR simulator is presented and discussed. Conclusion: The usage of the presented OTHR simulator makes assessing the reliability of a potential radar at predetermined locations automated, controllable and efficient, with results closely matching radar behavior in real operation.

Wide-Angle Frequency Scanning Metasurface Antenna Fed by Spoof Plasmonic Waveguide

We propose novel wide-angle frequency scanning metasurface antenna and antenna array fed by spoof plasmonic waveguide. The spoof plasmonic waveguide adopts the ultra-thin corrugated metallic strip which can support and propagate spoof surface plasmon polariton (SSPP) with high efficiency. By compensating the momentum difference between SSPP and free-space propagation modes via constant phase gradient, metasurface antenna can exhibit wide-angle and continuous radiation property according to the Generalized Snell's law. A prototype is designed, fabricated and measured, which consists of a wideband polarization rotating transmissive phase gradient metasurface (TPGM) placed a certain distance above spoof plasmonic waveguide. Such antenna works in a wideband range from 6.8 to 14.0 GHz, and the main beam can continuously scan from the forward direction to the backward direction with high efficiency. The measured results show that the scanning angle can reach 55°, which agree well with the simulated and theoretically calculated results. Furthermore, the proposed metasurface antenna can be combined easily as an antenna array with a simple feed network. Compared to single metasurface antenna, the antenna array exhibits the pencil-shaped directional radiation property, and the average gain of antenna array is obviously enhanced. The proposed frequency scanning metasurface antenna is of great value in the design of conformal antenna and the large aperture antenna array, especially on curved faces.

Performance Analysis of a Full-Duplex MIMO Decode-and-Forward Relay System With Self-Energy Recycling

This paper analyzes the performance of the full-duplex (FD) multiple-input-multiple-output (MIMO) decode-and-forward (DF) relay system in the presence of self-energy recycling (S-ER). Specifically, this work proposes an antenna allocation scheme for S-ER as well as analytically evaluates the performance of this proposed scheme in terms of spectral efficiency (SE), energy efficiency (EE), outage and symbol error rate (SER). Since, the self-interference (SI) is a major bottleneck in achieving the true potentials of FD communication, this work considers SI as an energy harvesting opportunity to enhance the EE of the system. The proposed analysis shows that reserving few antennas for S-ER at the FD-MIMO relay improves the EE, however, it reduces the antenna array gain at the relay for information transmission and reception. Thus, a slight degradation in the SE, outage and SER is observed. Further, an adaptive S-ER technique has been proposed which utilizes the antennas corresponding to the least channel gain with respect to information transmission and reception for S-ER. This adaptive S-ER technique improves the EE and also compensates for the slight degradation in the SE, outage and SER through adaptive antenna allocation. Closed-form expressions for the SE, EE, outage and symbol error rate have been derived for these S-ER techniques. In the end, simulations results are provided to validate the efficacy of the theoretical derivations.

Multi-CubeSat Relative Position and Attitude Determination Based on Array Signal Detection in Formation Flying

High-precision relative position and attitude measurement is crucial for consensus control and collision avoidance in multi-CubeSat formation flying. However, the traditional relative navigation systems comprise many sensors and are not suitable for CubeSats due to large volume, complexity, and cost. In this paper, we propose a new approach, called Multi-CubeSat relative State determination by Array Signal detection (MUSAS). The approach utilizes the existing communication systems and antenna arrays on CubeSats without the need of extra components. In MUSAS, deputy vehicle (DV) CubeSats in a formation broadcast orthogonal spread spectrum signals simultaneously. Two chief vehicle (CV) CubeSats receive and separate the signals and extract the multiple-input multiple-output channel response of each DV CubeSat. Then, by utilizing the bi-directional spatial spectrum estimation, the angles-of-arrival and angles-of-departure of the propagation paths from each DV CubeSat to the CV CubeSats are estimated. Finally, the attitudes and positions of all DV CubeSats relative to the CV CubeSats are determined using the derived rotation matrices. We have theoretically proved the proposed MUSAS algorithm and performed extensive simulations to compare its performance with existing methods. Furthermore, we also developed the testbed of MUSAS and conducted field experiments. The simulation and experiment results have verified that, by exploiting the spread spectrum gain and antenna array gain, MUSAS can achieve high accuracy in relative state determination, even using small antenna arrays and low transmission power.

Antenna Array Gain and Capacity Improvements of Ultra-Wideband Millimeter Wave Systems Using a Novel Analog Architecture Design

In this letter, we address the issue of beam-squinting encountered in ultra-wideband millimeter wave mobile communication systems. First, the beam-squinting effects on the antenna array gain and the usable bandwidth of these systems are analyzed. The obtained results show that, in ultra-wideband communication systems, beam-squinting causes loss in array gain and limits the achievable capacity. To mitigate these effects, a new analog architecture design, that improves the array gain and the achievable capacity, is proposed. The proposed architecture is most suitable for delay-sensitive or computational power constrained applications and does not require the computation of any compensation matrix in the digital domain. In addition, the exact expression for the array gain of the proposed analog architecture is derived. To further simplify the evaluation of the system performance, an approximated closed-form expression for the array gain is derived. Furthermore, to evaluate the performance of the proposed design, rigorous numerical results concerning different system parameters are provided in this letter.

An improved method of designing optimum microstrip Rotman lens based on 2D‐FDTD

In this article we propose an efficient method for analysis of microstrip Rotman lens using two-dimensional finite difference time domain (2D-FDTD). Both the dielectric and conductor losses are modeled in this method in order to achieve results which are in good agreement with 3D simulation. Using 2D analysis, the required simulation time is reduced considerably, which in turn, enables us to use the proposed analysis method in an optimization procedure. Based on this optimization procedure, we present an improved design of a microstrip Rotman lens in which both the efficiency and also the gain of isotropic antenna array are increased. In this design, the Rotman lens has 5 beam ports and 16 array ports and operates in Ku frequency band.

Perturbation of Electromagnetic Radiation of Downlink in Orthogonal Components on the GOES 16 Satellite by Planar Antenna Phase Array

The Geostationary Operational Environmental Satellite - GOES 16 has an arrangement of planar antennas for uplink and downlink communications in the L-band range, UHF frequency (1694,3/1694,9 MHz), 16 W transmission power and a planar antenna array gain of 28 dBi, for communication operations and data scanning. The structure of antennas in the form of arrangement combines high directivity in the electromagnetic signal and reduction of the broadside, which corresponds to a smaller angular variation. Assuming a communication channel for the GOES 16, from the phase arrangement of planar antennas using 4 rectangular radiant elements of 30 cm × 30 cm (patch) in the transmission (downlink), we defined an expression for the gain of the array of planar antennas and model an acceleration for the satellite, due to the effect of the electromagnetic perturbation it admits, antenna theory and the energy-momentum conservation laws. For a state vector - 04/02/2019, at 18h 40m 12.44s, we implemented a routine using numerical methods with the equation of movement in the form of Cartesian components, which can be used for both keplerian movement as well as adding the desired disturbing accelerations. We propagate its orbit over a period of 5 days, with a step of 10 minutes, and correlate the results of this propagation in the propagated orbital model without disturbance and with the disturbance of the acceleration on the satellite of electromagnetic origin, centered in the phase arrangement of flat antennas. The perturbative effect of this model is applied on GOES 16 taking into account satellite mass, antenna characteristics, radiated power and maximum antenna gain. The numerical integrator used for the solution of the satellite motion equation is based on the fourth and fifth degree Runge-Kutta method, and the results shows that the phase arrangement of planar antennas with the described configuration implies a significant electromagnetic disturbance, changing the components in the direction (radial, transverse and normal) and the coordinates XYZ.

Miniaturized Microstrip Patch Antenna Array for ISM Band Using Complementary Split Ring Resonator

These days patch antenna arrays are widely used in various communication systems. In this research design of miniaturized microstrip patch antenna array is presented. Miniaturization is achieved by reducing the mutual coupling between patch antenna elements. Complementary Split Ring Resonator is used to reduce the mutual coupling between patch elements in array. The mutual coupling between patch elements with and without resonator is calculated using High Frequency Structure Simulator. It has been observed that the mutual coupling between elements is reduced by 20 dB at 2.4 GHz by using resonator. Due to reduction in mutual coupling, patch antenna elements can be fabricated in less space which leads to compact antenna array system design. A miniaturization of 4.34% is achieved for two element Patch array without affecting the power gain and directivity of patch antenna array.

Compact antennas for mobile radio communications

A compact linearly polarized three-element antenna with sector radiation pattern and a cylinder antenna array with electrically switchable radiation pattern for base stations of mobile radio communication systems are presented. The operational frequency range of the antennas is 440-470 MHz. The single antenna has antenna gain not less than 7 dBi, while the antenna gain of the cylinder antenna array is not less than 5 dBi in case of omnidirectional radiation pattern and 10 dBi in case of sector radiation pattern.