Antenna Efficiency Research Articles

Design of Compact 2 × 2 Mimo Antenna for 5G Wireless Application

In this paper, a compact 2 X 2 MIMO antenna is proposed for 5G wireless applications. The proposed 2 X 2 MIMO antenna is designed using four compact circular monopole antennas which are optimized to operate from 3.6 to 57.7 GHz. The antenna structure consists of four orthogonal antenna elements of size 21 mm × 29 mm, which are spaced 1mm apart from each other. The antenna and the defective ground plane are placed on the same side of the substrate. It is demonstrated that MIMO system with 4- antennas produce very good isolation (>-20 dB) without using any additional isolating or decoupling techniques and antenna efficiency is also high. The antenna is simulated using CST Microwave Studio. The simulation results of the proposed MIMO antenna gives good radiation efficiency, Envelope Correlation Coefficient (ECC), improved bandwidth of 54.1 GHz, and optimum radiation characteristics. The proposed compact 2 X 2 MIMO antenna is suitable to operate under 5G wireless applications from 3.6 to 57.7 GHz. The applications of the proposed antenna also include broadcasting satellites, Modern radars, a 5GHz Wi-Fi channel, TV broadcasting satellites and microwave devices

Design of Dual-Band MIMO antenna for 5G applications

MIMO antenna are widely used in many areas for the great reception of signals. In transport industry for the development of automation and for the advancement they required efficient and high gain antenna transceivers. In this paper, single-element dual band antenna is used for 5G Vehicle to Everything (5G-V2X) application but the design will be enhanced to six-element for full coverage, on analysing single element. Three antennas of same structure as specified in this paper are arranged in a single substrate as a shape of triangle of combining all three, and similar structure is made in another substrate such that both are separated by a strip like structure and arranging both substrates that both triangularly arranged substrate forming a hexagonal structure from the top view. These will increase the coverage over 360° surrounds these will increase the gain over 9dB at mm-Wave range.

Wideband Dual Linearly Polarized Hollow- Waveguide Septum Antenna Array for Ku-Band Satellite Communications

This article presents a Ku-band full-corporate-feed dual linearly polarized (LP) hollow-waveguide (HW) septum antenna array. A modified low-profile septum polarizer, worked as the radiating element, is designed to push the radiation nulls out of the desired passband upon odd-mode excitation, which helps to achieve stable and consistent radiation performance for both H-pol and V-pol. Square coaxial lines are employed to realize two sets of full-corporate feeding networks with compact size, enabling close spacing between the two adjacent radiating elements. A magic-T based on the single-ridge waveguide is designed to provide in-phase and out-of-phase responses for the feeding networks so that the dual LPs can be achieved. A prototype covering 10.5–14.5 GHz is designed, fabricated, and measured for demonstration. Experimental results show that more than 17.3 dBi peak gain and better than 79% antenna efficiency for both polarizations are achieved within the desired frequency band. In addition, the antenna is free from grating lobes over the same frequency band.

Microstrip antennas on 3D-printed magneto-dielectric substrates: fabrication and efficiency study

AbstractMagneto-dielectric antennas (MDAs) provide small sizes, enhanced bandwidths, and frequency/polarization agility. We describe the fabrication and efficiency characterization at 0.4–0.8 GHz of five microstrip MDAs, whose gradually thicker substrates were 3D-printed using an off-the-shelf polylactic acid (PLA) filament doped with ferromagnetic particles. It was experimentally discovered that efficiency increases monotonically from 12% (−9.2 dB) to 37% (−4.3 dB) as substrate thickness goes from 1.6 to 4.3 mm; the rate is faster than expected for microstrip antennas. Numerical analysis indicated that the apparent magnetic loss tangent of the MD substrate experiences a threefold decrease as the 3D printer deposits more layers of iron-doped PLA. The MDAs exhibit radiation quality factors that are 3.7–7.2 times better than the dielectric counterparts. Moreover, a simple optimization of ground plane size could increase efficiency to 55% (−2.6 dB). The reduction in magnetic loss is attributed to a reduction in eddy current loss due to the separation of agglomerate iron particles. Therefore, despite the inherently lossy material used, the potential of 3D-printed MD substrates in providing acceptable antenna efficiencies is demonstrated together with unprecedented design freedom and fabrication flexibility.

Efficient and low SAR dual functional wearable antenna in RFID ISM and GPS L1 bands for positioning applications

Efficient and low SAR dual functional wearable antenna in RFID ISM and GPS L1 bands for positioning applications

Radial Line Planar Phased Array Using Electromechanically Rotated Helical Antennas

In this paper, we propose a novel radial line planar phased array in which helical antenna elements are individually rotated by their respective connected micromotors to realize dynamic beam-scanning. To our knowledge, this is the first radial line planar array (RLPA) that has antenna elements electromechanically rotated by their individual micromotors. To facilitate its fabrication, helix and its probe are directly metallized on a plastic shaft using molded interconnect device technology, and a motor shaft is press-fitted into the plastic shaft. We also present a new design methodology for RLPA, which combines the equivalent circuit theory and electromagnetic simulations of the unit cell element. The proposed procedure is practical to design an RLPA of antenna elements with arbitrary probe shape without large-scale full-wave analysis of the whole structure of the RLPA. We design, fabricate, and evaluate a 7-circle array with 168 helical antenna elements fabricated using molded interconnect device technology. The prototype antenna exhibits dynamic and accurate beam-scanning performance. Furthermore, the prototype antenna exhibits a low reflection coefficient (less than -17dB) and high antenna efficiency (above 77%), which validates the proposed design methodology.

A multi‐objective optimisation for compact wideband and efficient superdirective antenna arrays design using network characteristic modes

This paper introduces a procedure for multi-objective optimisation, for compact wideband superdirective antenna array design, using network characteristic modes. The two main objectives considered are the maximisation of the directivity in the end-fire direction, simultaneously with the minimisation of the input reflection coefficient in a large bandwidth. The proposed method is used thereafter for designing a three-element superdirective small Yagi antenna, with an overall dimensions of 0.4λ × 0.37λ × 0.18λ. The length of this mini yagi antenna is 60% shorter than a classical one, with the same performances of gain and bandwidth. The measured results show that the antenna bandwidth, maximum gain, and efficiency are of 11.2%, 8 dBi, and 95% respectively.

The Design and Development of a Microstrip Antenna for Internet of Things Applications.

The Internet of Things (IoT) has become a part of modern life where it is used for data acquisition and long-range wireless communications. Regardless of the IoT application profile, every wireless communication transmission is enabled by highly efficient antennas. The role of the antenna is thus very important and must not be neglected. Considering the high demand of IoT applications, there is a constant need to improve antenna technologies, including new antenna designs, in order to increase the performance level of WSNs (Wireless Sensor Networks) and enhance their efficiency by enabling a long range and a low error-rate communication link. This paper proposes a new antenna design that is able to increase the performance level of IoT applications by means of an original design. The antenna was designed, simulated, tested, and evaluated in a real operating scenario. From the obtained results, it ensured a high level of performance and can be used in IoT applications specific to the 868 MHz frequency band.By inserting two notches along x axis, we find an optimal structure of the microstrip patch antenna with a reflection coefficient of -34.3 dB and a bandwidth of 20 MHz. After testing the designed novel antenna in real IoT operating conditions, we concluded that the proposed antenna can increase the performance level of IoT wireless communications.

A Miniaturized Arc Shaped Near Isotropic Self-Complementary Antenna for Spectrum Sensing Applications

This paper presents the design of an arc-shaped near-isotropic self-complementary antenna for spectrum sensing application. An arc-shaped dipole with horizontal and vertical arms is used to achieve a near isotropic radiation pattern. The radiation pattern improved by adjusting the horizontal and vertical arm lengths. Simulated and experimental results show that the proposed antenna has an impedance bandwidth of 146% (2.4-18.4 GHz) for VSWR ≤ 2 with a good radiation pattern. In order to quantify the antenna performance, antenna gain variation, bandwidth, efficiency, and size have been compared with previously reported designs. It is shown that the proposed arc-shaped antenna can achieve nearly isotropic radiation patterns with a maximum radiation efficiency of 92%. The isotropic performance of the antenna has been characterized by observing the radiation pattern and solid angle. The FR4 substrate is used as a dielectric with relative permittivity 4.4 and loss tangent of 0.02. (εr = 4.4, h = 1.6 mm) The simulated and measured results are in good comparison, and the proposed design is a suitable candidate for spectrum sensing.

Effects of Mutual Coupling on Degree of Freedom and Antenna Efficiency in Holographic MIMO Communications

The holographic multiple-input-multiple-output (MIMO) communications refer to the MIMO systems built with ultra-dense antenna arrays, whose channel models and potential applications have attracted increasing attentions recently. When the spacing between adjacent array elements is larger than half wavelength, the effect of mutual coupling can generally be neglected in current antenna designs. However, in holographic MIMO communications, the influence of strong mutual coupling on antenna characteristics is inevitable, resulting in distorted radiation patterns and low radiation efficiencies. In this paper, starting from the analytical correlation and efficiency models, we investigate how the mutual coupling affects the capacity of a space-constrained MIMO system from the aspects of degree of freedom (DOF) and antenna efficiency. The involved fundamental concepts of correlation, DOF, efficiency and mutual coupling are crucial for both antenna and wireless-communication engineers when designing emerging MIMO communication systems.

A Circularly Polarized Parallel Plate Waveguide Lens-Like Multiple-Beam Linear Array Antenna for Satcom Applications

This work presents a full metal circularly-polarized lens-like antenna for Satcom applications at Ka-band. The antenna is composed of two continuous parallel plate waveguide (PPW) quasi-optical beamformers (QOBF), feeding an array of septum polarizers to generate circular polarization. The QOBFs operate over a wide band and provide a multi-beam coverage over a large field of view in the azimuthal plane, while maintaining a relatively simple mechanical design. The array of septum polarizers is based on a stepped profile to generate circular polarization with a good polarization purity in the uplink of Ka-band (27 - 31 GHz). The antenna is fully realized in aluminium. The antenna system provides 14 beams with alternating right/left handed circular polarization (RHCP/LHCP) with an axial ratio (AR) below 3 Db over an angular range of ±19° in the uplink of Ka-Band. The maximum gain in the azimuthal plane at 30 GHz is about 21 dB over the whole angular range, with a scan loss lower than 1.5 dB. The antenna efficiency is better than 78% for all beams in the operative band.

Design, Analysis and Fabrication of an Inside-Grooved Slotted Waveguide Array Antenna for HPM Applications

In this paper, a slotted waveguide array antenna (SWAA) is designed for S-band high-power microwave (HPM) applications. The single element of the array consists of ten Gaussian distributed slots on the broad wall of the waveguide, integrated with inside grooves. The 4-element SWAA configuration is designed to achieve a relatively high gain (24.6 dB) along with highly isolated (−24 dB) radiating elements. The gain enhancement and mutual coupling (MC) reduction is achieved by optimizing inside-grooved regions. An efficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 4$ </tex-math></inline-formula> power divider (PD) of identical phase and magnitude (−6 dB) at its output ports, is designed to feed the array elements. The radiation performance of SWAA is further improved by developing a dielectric radome. The proposed design is compact having dimensions <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.46\lambda _{0}\times 4.3\lambda _{0}\times 1.47\lambda _{0}$ </tex-math></inline-formula> , and offers return loss (RL) better than −25 dB with side lobe level (SLL) of −15 dB and −20 dB in E and H-plane, respectively. The designed array has 95.78% antenna efficiency over 3.8% measured bandwidth with 63% aperture efficiency. It has been demonstrated that the developed system, because of effective suppression of unwanted surface current, provides ±22° beam scanning without causing a significant reduction in its gain. The technique, without adding any complexity in the system, offered a 7% improvement in the gain when compared with a similar design.

Performance enhancement of patch antenna using nanocomposite substrate for modern wireless communication systems

As wireless communication systems become more sophisticated, exclusive features from antennas such as microstrip patch antennas become increasingly important. The choice of substrate material plays a significant role in determining a patch antenna's performance. Nowadays, Nanomaterials plays as important role as substrate in the design of patch antennas. In this work, the patch antenna design employs a new nano-magnesium ferrite material coated with FR4 and doped with dysprosium and erbium as the substrate. Computer simulation technology (CST) software is utilised to simulate the antenna. The results were compared with the antenna using substrate as only FR4 and FR4 coated Nanomaterial. It shows that the presence of nano coating improves antenna parameters such as Gain, Directivity, antenna efficiency etc., Thus the presence of nanomaterial enhances the antenna performance.

Nanosheets of two-dimensional photoluminescent lanthanide phosphonocarboxylate frameworks decorated with free carboxylic groups for latent fingerprint imaging.

The synthesis, structural characterization, exfoliation, and photophysical studies of two-dimensional (2-D) lanthanide phosphonates, named Ln(m-pbc); [Ln(m-Hpbc)(m-H2pbc)(H2O)] (Ln = Eu, Tb; m-pbc = 3-phosphonobenzoic acid) based on the phosphonocarboxylate ligand, are reported. These compounds are neutral polymeric 2D layered structures with pendent uncoordinated carboxylic groups between layers. The nanosheets were obtained by a top-down strategy involving sonication-assisted solution exfoliation and characterized by atomic force microscopy and transmission electron microscropy, showing lateral dimensions from nano- to micro-meter scales, and thicknesses down to several layers. The photoluminescence studies demonstrate that the m-pbc ligand acts as an efficient antenna toward Eu and Tb(III) ions. The emission intensities of dimetallic compounds are clearly enhanced after incorporation of Y(III) ions due to the dilution effect. Ln(m-pbc)s were then applied for labelling latent fingerprints. It is worth noting that the reaction between active carboxylic groups and fingerprint residues benefits the labelling, showing efficient imaging for fingerprints on all kinds of material surfaces.

A compact miniaturized multiband monopole four L-strip antenna for mobile phone/S-band/WLAN/X-band applications

A compact multiband monopole antenna with four L-strips and microstrip feed is proposed for mobile phone, S-band, Wireless Local Area Networks, and X-band applications. The antenna is simulated on a Flame Retardant-4 (FR-4) epoxy substrate with a dielectric constant of (εr)= 4.4 and loss tangent of 0.01. The antenna is simulated using High-Frequency Structure Simulator (HFSS) software. The antenna consists of four L-shaped cuts in the patch, with the ground plane acting as the monopole radiator. The total miniaturized size of the antenna is 30 × 30 × 0.8 mm3, and the monopole ground plane size is 30 × 6 mm2. The proposed antenna has better performance in terms of total peak gain compared to other similar antennas. It is a compact and efficient antenna with good performance. It can be used for a variety of applications, such as mobile phones, wireless communication devices, and radar systems.

Wideband 5G Antenna Gain Enhancement Using a Compact Single-Layer Millimeter Wave Metamaterial Lens

This paper presents a very compact, wideband, and enhanced-gain antenna for 5G applications. A simple single-layer millimeter wave (mm-wave) metamaterial lens (meta-lens) is used to improve the gain, aperture efficiency, and gain bandwidth of a slotted-patch antenna over a wide range of frequencies from 25 GHz to 31 GHz. The lens exhibits a metamaterial negative refractive index behavior, which is attributed to a substantial gain enhancement of around 4-5 dBi over the whole band compared to the gain values of the slotted patch antenna alone. The lens’s unit cell comprises a simple single-layer split ring resonator (SRR) whose dimensions are carefully chosen to improve transmitted power and suppress absorbed and reflected power. The meta-lens consists of 8×8 subwavelength SRR unit cells. Each cell has an area of 1.6×1.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , it is located in the near-field region closely above a slotted patch antenna to produce a total antenna size of 12.8 ×12.8 ×7.27mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ( 1.2 λ × 1.2 λ × 0.68 λ, where λ is the free space wavelength at 28 GHz). The maximum gain of the proposed antenna is 12.7 dBi, the 1 dB gain bandwidth is 18%, the maximum aperture efficiency is 92%, and the -10 dB impedance bandwidth (10 dB B.W.) is 17%. This excellent combination of essential metrics is hard to realize at mm-wave using narrowband antenna structures (microstrip patch antennas), and the aperture efficiency is the highest thus far for such a class of antennas.

Efficiency-Driven Design for Planar Antennas With Lossy Materials

This article demonstrates a design strategy for improving the radiation efficiency of a planar antenna made of a layered conductor of MXene with modest conductivity on a lossy PDMS substrate. New methods to reduce the conductor loss and the dielectric loss are proposed. On the one hand, the conductor loss is minimized by identifying the location of high current density on the antenna radiator, and then accordingly altering its shape to redistribute the surface currents as uniformly as possible. On the other hand, the dielectric loss is reduced by employing a folded ground plane with elevated edges. This ground plane structure reduces the concentration of the electric field in the dielectric substrate and thus minimizes the power dissipation due to dielectric loss. The improvement techniques are implemented starting from a standard U-slot microstrip antenna. The method demonstrates to improve the radiation efficiency significantly by an average of 14% for a microstrip antenna fabricated using MXene conductor with a sheet resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 {\Omega }$ </tex-math></inline-formula> /square and a lossy PDMS substrate. Importantly, the proposed method can preserve the overall antenna size and the operating frequency band. The optimized antenna exhibits a high radiation efficiency of 71% and offers a wide impedance bandwidth of 56% covering operation for the 5 GHz WLAN band.

Theory of a VLF Circular-Loop Antenna in an Anisotropic Magnetoplasma

The circular-loop antenna is one of the most basic antenna forms for very low frequency (VLF: 3–30 kHz) space-borne transmitting systems. However, the theoretical progress of the loop antenna in an anisotropic plasma is slower than that of the linear antenna due to its complexity. This article studies the theory of a VLF circular-loop antenna located in an anisotropic magnetoplasma. The current integral equation of the current is formulated by deriving the exact kernel function and boundary condition. By taking both the effects of O-wave and E-wave into consideration, the current distribution and input impedance of a circular-loop antenna are solved via the method of moments along with the numerical techniques. The results show that the current amplitude decreases with the loop radius. As the size of the loop increases, the current distribution resembles a cosine function with its phases jumping at several positions. Moreover, the input impedance of the antenna increases as the radius and operating frequency increase. The proposed approach is validated by comparing the computed impedance with that simulated by the commercial software FEKO. The preliminary study of VLF loop antenna theory can offer theoretical guidance in antenna design and efficiency improvement for actual VLF space-borne transmitting systems.

Design of rectangular microstrip patch antenna with E-slot

The integration of an E-slot within the conventional microstrip patch antenna structure offers improved radiation characteristics and bandwidth. This research presents the design and analysis of a rectangular microstrip patch antenna with an E-slot. The proposed antenna is designed to operate at a specific frequency in the microwave range. The design process involves determining the dimensions of the rectangular patch, feedline, and E-slot to achieve the desired resonance frequency. The simulation and optimization are carried out using electromagnetic simulation software, considering the dielectric substrate properties and other relevant parameters. The E-slot is strategically placed within the patch structure to enhance the antenna's performance. It acts as an additional resonating element, contributing to increased bandwidth and improved radiation characteristics, such as gain and directivity. The integration of the E-slot modifies the current distribution on the patch, resulting in enhanced radiation properties. The performance of the proposed antenna is evaluated through various parameters, including return loss, radiation pattern, and bandwidth. Overall, the rectangular microstrip patch antenna with an E-slot presents a promising solution for achieving enhanced performance in terms of bandwidth and radiation characteristics. The proposed design opens up possibilities for further advancements in microstrip antenna technology, facilitating the development of an efficient and compact antenna structure for modern wireless applications.

Highly Efficient Circularly Polarized Radial Line Slot Array Antenna Using Non-Uniform Slot Density for 5G Communication System

Highly Efficient Circularly Polarized Radial Line Slot Array Antenna Using Non-Uniform Slot Density for 5G Communication System