Printed Dipole Antenna Research Articles

Analysis of 2 × 2 MIMO array loaded by artificial magnetic conductor with improved gain, isolation, and bandwidth using equivalent transmission line model for indoor wireless base station

A low profile printed dipole antenna (PDA) backed by broadband Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for wireless communications. First, a suggested PDA with a pair of microstrip dipoles excited by an E-shaped microstrip feedline is used to expand the bandwidth in the range of 5.96–7.04 GHz (S11 ≤ −10 dB). Then, the suggested Giuseppe Peano fractal AMC surface as a reflector of the antenna is inserted into the PDA to gain improved radiation efficiency. The PDA with the 6 × 6 Giuseppe Peano AMC array exhibits −10 dB measured impedance bandwidth of 4.95–7.05 GHz (35%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 38%, enhanced gain up to 8.2 dBi, and excellent impedance matching (at least −20 dB) with directional radiation patterns. The novel AMC unit cell is realized based on the Giuseppe Peano fractal patch to operate at 6.10 GHz with an AMC bandwidth of 5.15–7.10 GHz (32%). Besides, by loading 12 × 12 AMC reflector into the four-element array of PDA, low profile wideband structure with enhanced radiation properties are achieved. The measured results show the broad bandwidths of 5–7 GHz for all elements with enhanced gains and good isolations between the elements (more than 24 dB) for multiple-input multiple-output (MIMO) systems.

Analysis of gyrobianisotropic media effect on the input impedance, field distribution and mutual coupling of a printed dipole antenna

In this paper, we present an analytical study for the investigation of the effects of the magnetoelectric elements of a reciprocal and nonreciprocal bianisotropic grounded substrate on the input impedance, resonant length of a dipole antenna as well as on the mutual coupling between two element printed dipole array in three configuration geometries: broadside, collinear and echelon printed on the same material. This study examines also the effect of the considered bianisotropic medium on the electric and magnetic field distributions that has been less addressed in the literature for antenna structures. Computations are based on the numerical resolution, using the spectral method of moments, of the integral equation developed through the mathematical derivation of the appropriate spectral Green’s functions of the studied dipole configuration. Original results, for chiral, achiral, Tellegen and general bi-anisotropic media cases, are obtained and discussed with the electric and magnetic field distributions for a better understanding and interpretation. These interesting results can serve as a stepping stone for further works to attract more attention to the reciprocal and non-reciprocal Tellgen media in-depth studies.

High‐isolated broadband eight‐element linear multi‐input multi‐output array over artificial magnetic surface for wireless and sub‐6 GHz 5G communications

SummaryA low‐profile eight‐element printed dipole antenna (PDA) array backed by broadband rhomboid artificial magnetic conductor (AMC) is introduced for wireless communication systems. By loading a 4 × 27 AMC reflector into the eight‐element array of PDA, a low‐profile wideband structure with enhanced radiation properties is achieved. The measured S parameters show the broad bandwidth from 4.75 to 7.05 GHz in C‐band with enhanced gains of eight elements (more than 8 dBi) and the suitable isolation between the array elements of more than 23 dB for multi‐input multi‐output (MIMO) systems. The suggested PDA with a pair of the microstrip meandered folded poles excited by an E‐shaped microstrip feedline expands the bandwidth in the range of 5.85–6.95 GHz (S11 ≤ −10 dB). The novel AMC unit cell is realized based on the recognized method as rhomboid coupled parasitic patches. The rhomboid AMC design operates at 6.26 GHz with an AMC bandwidth of 5.20–7.24 GHz (32.8%). Then, the suggested rhomboid AMC surface as a reflector of the antenna is inserted into the PDA to exhibit −10 dB measured impedance bandwidth from 4.94 to 6.93 GHz (more than 33%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 34%, enhanced gain up to 8 dBi, and excellent impedance matching (at least −20 dB) with directional radiation patterns.

Radiation Properties Improvement of 1 × 4 Array of Wideband Printed Antenna Supported by AMC Surface for Vehicular MIMO Systems

AbstractA 1 × 4 array of printed dipole antenna (PDA) with a broadband rhomboid artificial magnetic conductor (AMC) is introduced. A suggested PDA using a pair of microstrip dipoles with unequal arms excited by a T‐shaped microstrip feedline expands the bandwidth in the measured range of 5.27–6.74 GHz. Then, the suggested 3 × 3 AMC reflector is inserted into the PDA to exhibit −10 dB measured impedance bandwidth from 4.20 to 7.11 GHz for WLAN and WiMAX applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 46.72%, enhanced gain up to 8.4 dBi, and excellent impedance matching with unidirectional radiation patterns. The novel AMC unit cell operates at 6.20 GHz with an AMC bandwidth of 5.09–7.21 GHz. Also, by loading a 3 × 8 AMC periodic array on a FR4 substrate with 3 mm thickness underneath the four‐element array of PDA with a gap distance of 3 mm, a low‐profile wideband structure with enhanced radiation properties is achieved. The measured S‐parameters show the broad bandwidth from 4.26 to 7.28 GHz with enhanced gains and efficiencies of all elements. Besides, the suitable isolation between the array elements of more than 30 dB for multiple‐input multiple‐output (MIMO) systems is achieved by applying various polarized directions of PDAs and loading the 3 × 8 periodic AMC reflector. Finally, the proposed MIMO design introduces remarkable advantages of good size reduction and bandwidth enhancement, low‐profile antenna with high stable gain, high efficiency and large isolation, and unidirectional radiation patterns with reduced backside direction.

Gyrotropic reciprocal bianisotropic metamaterial printed dipole antenna: Investigation of negative input impedance and mutual coupling

This paper surveys a new class of electromagnetic materials. The emphasis is on the bianisotropic medium; a complex material which has never been applied in antenna design. In this context, we investigate the behavior of the magnetoelectric elements of the gyrotropic reciprocal bianisotropic medium used as a grounded substrate by studying their effects on the input impedance and mutual coupling of a printed dipole antenna. Numerical integrative equation calculations are carried out using the spectral method of moments (SMoM) based on the analytical derivation of the appropriate spectral Green’s functions for the considered dipole configuration. The obtained results reveal a change in the sign of the real part of the input impedance. This is mainly due to the complex property of the considered medium. The medium has also minimized the input impedance ∼4 times (1kΩ); this can help in device matching. This medium has shown a significant impact on the input impedance as well as the antenna array coupling. The design miniaturization possibility is an important result of this research in the design of antenna arrays.

Broadband printed dipole antenna with integrated balun and tuning element for DTV application

This paper presents the broadband printed dipole antenna design with an integrated balun and tuning element for DTV applications. The proposed technique is a unique tuning mechanism that is straddled between the gap of the proposed dipole antenna. This enables the frequency range of the dipole antenna to be adjusted to tightly cover the specified Digital TV band, thereby mitigating interference from signals outside the band that would otherwise degrade the quality of the DTV signal. The measured results confirm that the proposed antenna covers an impedance bandwidth of 414.5 MHz from 457.7 to 872.2 MHz, which covers the frequency band of DTV systems (470–862 MHz). Furthermore, the proposed antenna has excellent omnidirectional radiation with a maximum realized gain of 2.95 dBi. These results demonstrate the suitability of the antenna for DTV applications.

Antenna Optimization Based on Auto-Context Broad Learning System

To enhance the efficiency of antenna optimization, surrogate model methods can usually be used to replace the full-wave electromagnetic simulation software. Broad learning system (BLS), as an emerging network with strong extraction ability and remarkable computational efficiency, has revolutionized the conventional artificial intelligence (AI) methods and overcome the shortcoming of excessive time-consuming training process in deep learning (DL). However, it is difficult to model the regression relationship between input and output variables in the electromagnetic field with the unsatisfactory fitting capability of the original BLS. In order to further improve the performance of the model and speed up the design of microwave components to achieve more accurate prediction of hard-to-measure quality variables through easy-to-measure parameter variables, the conception of auto-context (AC) for the regression scenario is proposed in this paper, using the current BLS training results as the prior knowledge, which are taken as the context information and combined with the original inputs as new inputs for further training. Based on the previous prediction results, AC learns an iterated low-level and context model and then iterates to approach the ground truth, which is very general and easy to implement. Three antenna examples, including rectangular microstrip antenna (RMSA), circular MSA (CMSA), and printed dipole antenna (PDA), and 10 UCI regression datasets are employed to verify the effectiveness of the proposed model.

Two-Dimensional Millimeter-Wave Beam-Switching Antenna Using an ELC Meta-Lens

A 2-D beam switching dipole antenna working at 60 GHz is proposed. To realize this, a folded electric-field coupled (ELC) resonator is designed to achieve a high-refractive-index medium in the band of 57–64 GHz. By integrating an array of ELC resonators in the off-center of a printed dipole antenna in the E- and H-planes forming high-refractive-index medium lenses (metalenses) in each plane, the main beam direction is manipulated to generate 2-D beam switching at 60 GHz. In the final configuration, six slabs each containing three folded ELC inclusions are incorporated vertically in front of the dipole antenna in the azimuth plane to tilt the radiation beam by 25° in the H-plane. In addition, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times5$ </tex-math></inline-formula> array of folded ELC resonators is added into the elevation plane of the antenna substrate to deflect the radiated beam in the E-plane by 20°. The measurement results confirm that the radiated beam is tilted by 25° and 20° in the H- and E-planes, respectively, over a frequency band of 57–64 GHz. The measured antenna gain is 10.7 dBi at 61 GHz, the measured reflection coefficient is below −10 dB over 57–64 GHz, and the measured radiation efficiency of the antenna is 82% at 60 GHz.

Printed Dipole Antenna Array With Reconfigurable Feeding Network for Wide Elevation Angle of U2X Communications

In this paper, a printed dipole antenna array with reconfigurable feeding network for wide elevation angle of U2X communications is presented. The proposed array consists of a printed 8-element dipole antenna array in the top substrate, two supports with a tapered balun and two reflectors with the reconfigurable feeding network in the bottom substrate. To achieve high gain and wide beam coverage, the proposed reconfigurable feeding network consists of single-pole double-throw (SPDT) switches, single-pole three-throw (SP3T) switches, Wilkinson power dividers, and hybrid couplers. The proposed array antenna forms a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3$ </tex-math></inline-formula> beam consisting of broadside and end-fire beams based on the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$y$ </tex-math></inline-formula> -axis using a reconfigurable feeding network. The measured impedance bandwidth, peak gain, and half-power beamwidths (HPBWs) at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\phi $ </tex-math></inline-formula> =0° and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\phi $ </tex-math></inline-formula> =90° of the proposed array are approximately 1250 MHz (25%), 7.9 dBi, 197° and 100°, respectively. The overall volume size of the proposed array is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$75\times 96 \times 21$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.3{\lambda _{0}}{\times } 1.6{\lambda _{0}}{\times } 0.4\lambda _{0}$ </tex-math></inline-formula> at 5.1 GHz).

High gain, high isolation, and low‐profile two‐element MIMO array loaded by the Giuseppe Peano AMC reflector for wireless communication systems

A low-profile printed dipole antenna (PDA) backed by a broadband Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for wireless communications. A suggested PDA with a pair of microstrip dipoles excited by an E-shaped microstrip feedline is used to expand the bandwidth range of 5.5–6.96 GHz (S11 ≤ −10 dB). Then, the suggested Giuseppe Peano fractal AMC surface as a reflector of the antenna is inserted into the PDA to improve radiation efficiency. The PDA with the 4 × 4 Giuseppe Peano AMC array exhibits −10 dB measured impedance bandwidth from 4.25 to 7.10 GHz (50.2%) for the wireless local area network and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 50.5%, enhanced gain up to 8.2 dBi, and excellent impedance matching (at least −19 dB) with uni-directional radiation patterns. The novel AMC unit cell is realized based on the Giuseppe Peano fractal patch to operate at 6.10 GHz with an AMC bandwidth of 5.15–7.10 GHz (32%). Besides, by loading a 4 × 8 AMC reflector into the two-element array with diverse polarisations, a low profile wideband printed structure with enhanced radiation properties is achieved. The measured results show the broad bandwidths from 4.3 to 7.05 GHz for two elements with enhanced gains and good isolations between the elements (more than 28.5 dB) for multiple-input multiple-output (MIMO) systems.

A Low Cost, High-Reliability Receiver System for Reading Passive RFID Tags

Radio-Frequency Identification (RFID) is one of the leading enabling technologies of the Internet of Things (IoT) at low cost and high granularity scenarios. The cost of implementing IoT applications concerns the development and operation of receiver systems for reading labels. In this paper, we propose a low-cost receiver system based on off-the-shelf components allied to the development of a microstrip antenna. The proposed system is capable of receiving and processing digital signals scattered back from a passive RFID tag. The proposal relies on a Python application embedded in Raspberry Pi hardware, in which a bank of digital filters processes the signal. The proposal separates the received signal into sub-bands and implements a decision-maker that detects and codes radiofrequency carriers’ presence in sub-bands. Simulation using artificial random noise proves that the proposed and implemented decision-maker achieves 92% reliability for a Signal-to-Noise ratio between 1.6 dB and 2.3 dB. The evaluation of the printed dipole antennas pair for the RFID receiver system indicates a return loss of 19.22 dB for operation at 915 MHz.

Design of a Novel Wideband Leaf-Shaped Printed Dipole Array Antenna Using a Parasitic Loop for High-Power Jamming Applications.

This paper proposes a novel wideband leaf-shaped printed dipole antenna sensor that uses a parasitic element to improve the impedance matching bandwidth characteristics for high-power jamming applications. The proposed antenna sensor consists of leaf-shaped dipole radiators, matching posts, rectangular slots, and a parasitic loop element. The leaf-shaped dipole radiators are designed with exponential curves to obtain a high directive pattern and are printed on a TLY-5 substrate for high-power durability. The matching posts, rectangular slots, and a parasitic loop element are used to enhance the impedance matching characteristics. The proposed antenna sensor has a measured fractional bandwidth of 66.7% at a center frequency of 4.5 GHz. To confirm the array antenna sensor characteristics, such as its active reflection coefficients (ARCs) and beam steering gains, the proposed single antenna sensor is extended to an 11 × 1 uniform linear array. The average values of the simulated and measured ARCs from 4.5 to 6 GHz are −13.4 dB and −14.7 dB. In addition, the measured bore-sight array gains of the co-polarization are 13.4 dBi and 13.7 dBi at 4 GHz and 5 GHz, while those of the cross-polarizations are −4.9 dBi and −3.4 dBi, respectively. When the beam is steered at a steering angle, θ0, of 15°, the maximum measured array gains of the co-polarization are 12.2 dBi and 10.3 dBi at 4 GHz and 5 GHz, respectively.

Effect analysis of the general complex reciprocal gyro-bianisotropic metamaterial medium on the input impedance of a printed dipole antenna

The aim of this paper is to present an analytical study for the investigation of the reciprocal metamaterial gyro-bianisotropy effects on the input impedance of a dipole antenna. This study is based on the numerical resolution, using the spectral method of moments (SMoM), of the integral equation developed through the mathematical derivation of the appropriate spectral Green’s functions of the studied dipole configuration. The original obtained results are discussed and showed good agreements with the isotropic studied cases available in published literature. It is found that the imaginary valued magnetoelectric elements (chiral medium) exhibit an inverse effect on the resonant length compared to purely real elements (Tellegen medium), while negative elements decrease the input impedance. Combination of the two cases has led to more general complex media with further inspiring features.

An Optimization Driven Approach for Designing Touch Sensor Panels for Integration With Antennas

Objective: We present a systematic method of integrating 5G printed antennas with bezel-less capacitive touch sensor panels (TSPs). Need: With these displays, only the space underneath the TSP is available for antenna integration. But, the electrodes of contemporary TSPs are so closely packed that they reflect impinging electromagnetic (EM) waves, distorting the radiation patterns of the antenna placed underneath. Thus, the system requires more power to compensate for these reflections and maintain high quality data transfer. Method: We utilize pattern search optimization to design the touch sensing electrodes as frequency selective surfaces with a pass-band at the operating frequency of the antenna. We carry out the optimization initially at 4.7GHz to demonstrate its advantages with respect to antenna integration. We fabricated the optimized TSP and measured its transmission and reflection coefficients for a normally-incident plane wave. The designed TSP is broadband and has a measured bandwidth of 8.4% at 4.76GHz. We explore the optimization process further for other frequencies in the 5G-NR frequency range 1 spectrum (4GHz, and 5.5GHz) to show its robustness. Touch performance: We evaluate the touch sensing response of the optimized TSP using quasielectrostatic simulations. Results: We designed, optimized and realized a TSP for a 4.7GHz antenna. We integrated the optimized and conventional TSPs with a printed dipole antenna and measured the radiation patterns of the antenna underneath the TSP at 4.7 GHz. The measured radiation pattern for the optimized TSP case was nearly identical to the free-space pattern of the dipole. With our proposed solution, antennas can claim the space underneath the TSP which is paramount for 5G wireless standards that require multiple antennas for intelligent radios.

A wideband Circular polarization cross printed dipole antenna with four quadrants parasitic

The cross printed dipoles antenna is the best solution to generate wide band circular polarization, in this design prepared cross rectangular printed dipoles (antenna1) then added four inner quadrants parasitic (antenna2) with perfect arrangement and excellent dimensions. The quadrants, (inner parasitic) rotate sequentially round the crossed dipole, are used to persuade new resonance and increase the activity bandwidth, additional improving the AR bandwidth. The results show that the antenna achieves an impedance bandwidth (IBW) of 88.38% (4.66-12.04 GHz) for |S11| < −10 dB and a wide axial ratio bandwidth (ARBW) of 55.80% (5.75-10.2 GHz). The proposed antenna would be utilized in C-band applications and for wireless local area network (WLAN) applications. The structures modelled and analysed by the Ansoft’s HFSS simulation software.

Performance enhancement of microstrip antenna using artificial magnetic conductor reflection phase characteristics

This paper investigates the behavior of a dipole antenna near the perfect electric conductor, perfect magnetic conductor, and artificial magnetic conductor (AMC). The phase variations due to reflector reflection coefficient and the distance between antenna and reflector are analyzed, and their effect on the antenna radiation patterns are studied for different frequencies. The cause of a null occurrence in the broadside direction of radiation pattern when using the AMC (or HIS) as a reflector is explored. It is shown that this degradation is due to the phase of the reflected waves at different angles from the reflector surface and this phenomenon may occur for any type of reflector. In the next step, a new broadband unit cell is presented. By changing the AMC reflection feature and the distance between the antenna and the ground plane for three different states, the performance of the printed dipole antenna is improved. The maximum gain of the antenna is enhanced by approximately 7 dB, 9 dB, and 9 dB for three different cases of AMC reflectors. Moreover, the 3 dB max-gain bandwidth of the structures are 33.81%, 29.17% and 20.84%, with profile size of 0.16λ, 0.4λ, and 0.4λ, respectively. All cases of the antenna with AMC structures have been fabricated and the measurement results are presented.

Probe‐fed dipole antenna with parasitic patches for wideband and wide‐scanning planar phased arrays

A probe-fed dipole antenna with parasitic patches is proposed in this study as the element for wideband and wide-scanning planar-phased arrays. Parasitic patches are used to realize wideband performance by significantly reducing the active input impendence. The printed dipole antenna with parasitic patches is directly matched with the subminiature version A (SMA) connector through the modified probe structure. The cell size is 0.5 × 0.5 × 0.145 λhigh3. The planar and low-profile characteristics make it suitable for modular phased array applications. It is shown that the infinite array simulation results achieve 45.2% bandwidth (7.86–12.45 GHz) with active voltage standing wave ratio (VSWR) < 2 at broadside, 60° scans in E-, D-planes and 50° scan in H-plane. An 8 × 8 prototype array has been manufactured and measured to validate the proposed design and the active element patterns agree well with simulation results.

A Printed Dipole Antenna for 5G Millimeter Wave Application

An essential point of the technology in the 5th generation (5G) communications is to utilize the available spectrum in high frequencies beyond 20GHz, whose corresponding wavelengths reach a relatively small millimeter magnitude. To cope with the challenge of such short wavelengths, this paper has proposed a printed dipole antenna with a geometric structure that two dipole arms are patched on opposite sides of a FR4 substrate fed by a microstrip line and triangular balun. Simulations have shown that the proposed antenna possesses a relatively effective performance operated at 21.6 ∼ 25.4GHz with a maximum gain of 1.62dB. Additionally, the impact of some geometric parameters, such as the sizes of dipole arms and triangle baluns, are also discussed in this paper.

MIMO/Diversity Antenna with Neutralization Line for WLAN Applications

A four-port multi-input-multi-output (MIMO) antenna is designed for the WLAN access point applications. The prospective antenna consists of four double-layered printed dipole antennas (DLPDAs), where two elements are designed to resonate at a frequency of 2.45 GHz and the resonant frequency of the other two elements is 5.8 GHz. The resonant bandwidths of the DLPDAs are 24.7% (2.09–2.68 GHz) and 28.9% (4.73–6.33 GHz) at 2.45 GHz and 5.8 GHz, respectively. The proposed MIMO antenna is printed on the FR-4 substrate of size 45 mm × 60 mm × 1.6 mm. A decoupling network is introduced in the center of the proposed antenna to achieve high isolation between resonating elements. The decoupling arrangement is a combination of four metal strips and a circular loop that acts as a neutralization line. It opposes the direct coupling current and provides isolation of around 20.55 dB at 2.45 GHz and 33.08 dB at 5.8 GHz.

Analysis of the Combinatory Effect of Uniaxial Electrical and Magnetic Anisotropy on the Input Impedance and Mutual Coupling of a Printed Dipole Antenna

The main objective of this work is to investigate the combinatory effects of both uniaxial magnetic and electrical anisotropies on the input impedance, resonant length and the mutual coupling between two dipoles printed on an anisotropic grounded substrate. Three different configurations: broadside, collinear and echelon are considered for the coupling investigation. The study is based on the numerical solution of the integral equation using the method of moments through the mathematical derivation of the appropriate Green’s functions in the spectral domain. In order to validate the computing method and evaluated MatlabⓇ calculation code, numerical results are compared with available literature treating particular cases of uniaxial electrical anisotropy; good agreements are observed. New results of dipole structures printed on uniaxial magnetic anisotropic substrates are presented and discussed, with the investigation of the combined electrical and magnetic anisotropies effect on the input impedance and mutual coupling for different geometrical configurations. The combined uniaxial (electric and magnetic) anisotropies provide additional degrees of freedom for the input impedance control and coupling reduction.