Antenna Performance Research Articles

Magnetic-electric dipole circularly polarized antenna with unidirectional radiation pattern with improved characteristics

Abstract In this paper, a compact unidirectional antenna consisting of a planar electric dipole and a shortened connecting element is introduced. This antenna is excited by a Γ-shaped feeding line. A wide impedance bandwidth in the frequency range of 1.3–3.3 GHz is observed in the output performance. Sufficient main lobe and low level back lobe have been introduced as other characteristics of the structure, based on radiation patterns. The antenna design process is evaluated step-by-step and using parametric study based on the antenna geometry. One of the main features of the desired antenna is the realization of circular polarization in a high percentage of the operational bandwidth 1.5–3.3 GHz. The radiation patterns of the orthogonal planes E-field and H-field along with the left-handed and right-handed circular polarization patterns for the desired antenna have been extracted and analyzed. A three-dimensional structure in the form of stacked stepped disks (SSD) is introduced to increase overall performance of antenna. There is an acceptable similarity between the E-field and H-field page patterns, which shows the accuracy of the design process. On the other hand, for studying the circular polarization, left-handed and right-handed patterns based on the main beam direction and orthogonal polarization level have acceptable performance. The maximum overall gain of the antenna in the designed frequency band is near to 13 dB.

Performance enhancement of Graphene-Based elliptical patch antenna for THz applications

The advancement of wireless communication applications has proliferated in recent years. The antenna design is crucial in evaluating the effectiveness of most of these wireless communication applications that demand extensive bandwidth and a lofty data rate. THz (Terahertz) band is becoming a key factor for advanced wireless communication applications. The design of microstrip patch antennas in the THz band is preferred as one of the most significant for advanced wireless applications. This paper proposed an elliptical patch antenna with a T-shape slot on the patch and partial ground methods to meet the speed demand of advanced wireless communication systems. The overall size of the antenna is 160 × 120 µm2. We investigated the antenna performance by using computer simulation technology (CST) simulation software. The simulation results indicate that our proposed antenna improves the bandwidth by 0.72 THz (720 GHz) with a return loss suppression of 12 dB. Moreover, the gain and efficiency of the proposed antenna show satisfactory enhancement. Based on the concept of a T-shape slot on the patch and partial ground method, we confirm the performance improvement of the proposed antenna through simulation results.

Evaluation of L6 augmentation signal reception characteristics and positioning accuracy of compact and lightweight GNSS antennas

Applications requiring outdoor position estimation, such as unmanned construction and delivery automation, focus on receiving global navigation satellite system (GNSS) correction information from satellites for high-precision positioning. In particular, the delivery of correction information for the Galileo high-accuracy service (HAS) and quasi-zenith satellite system (QZSS) centimeter-level augmentation service (CLAS) is based on a new frequency band called L6. The L6 signal is a new type of GNSS signal, and a GNSS antenna corresponding to the frequency of the L6 signal (1275.46 MHz) is required to receive and decode the correction messages. The reception characteristics of the L6 signal are important for receiving correction information. However, the reception performance of antennas supporting the new L6 signal has not been evaluated. Therefore, in this study, we evaluate the reception characteristics of the L6 signal of a compact and lightweight L6-compatible antenna, and the multipath characteristics, which are the fundamental performance of the antenna that affects high-precision positioning. In a 24-hour static test, each antenna’s signal reception performance and multipath characteristics were evaluated, and significant differences were found in performance among the antennas capable of receiving the L6 signal. Furthermore, in a kinematic test, we evaluated high-accuracy positioning using QZSS CLAS with multiple antennas and showed that centimeter-level positioning using L6 augmentation signals is possible even with compact and lightweight GNSS antennas. These evaluations provide guidelines for antenna selection when high-precision positioning using L6 signals is employed in various applications.

A Multipolarized Traveling-Wave Series-Fed Antenna Array Based on Patch

In this paper, a simple broadband multipolarized traveling-wave series-fed antenna array is proposed. The radiation unit cells are multiple squares. The square unit cell will change between circular polarized (CP) and linear polarized (LP) through a reasonable feeding mode. By adjusting the equivalent length of the unit cell, the Q value of the antenna can be reduced, resulting in the increase of the bandwidth of the array. The array consists of seven-unit cells and dual-port feeding. The unit cells which are connected by a microstrip line are arranged in a circular array. A reasonable layout of unit cells can achieve good port isolation of the array. The polarization performance of the array antenna is the same as that of the unit cell. The antenna is fabricated and measured. The measured results are consistent with the simulated results.

Wideband Omnidirectional Antenna Featuring Small Azimuthal Gain Variation.

Wideband omnidirectional antennas are essential components in radio monitoring and communication systems, enabling the reception of signals from all directions over a wide bandwidth. This paper presents a novel wideband omnidirectional antenna design that achieves a 1-dB gain variation across its azimuthal plane within a bandwidth of 1.8 GHz to 7.77 GHz. The antenna's exceptional performance is attributed to two flower-bud-shaped monopoles that, through pattern superposition, generate a wideband omnidirectional radiation pattern. Analysis shows that the use of a circular ground plane also reduces the azimuthal gain variation. Additionally, an embedded matching structure integrated into the antenna's base enhances the impedance bandwidth without compromising its compact size. Analytical investigations demonstrate that the matching structure effectively behaves as a five-order LC circuit, explaining its wideband matching capabilities. Furthermore, structural modifications effectively reduce side lobe levels, ensuring minimal interference. Experimental measurements corroborate the antenna's omnidirectional radiation pattern and confirm that the azimuthal gain variation remains within 1-dB throughout its bandwidth, while maintaining an S11 below -10 dB from 1.8 GHz to 7.7 GHz. The antenna's bandwidth overlaps with the spectrum intensively used in mobile communication technologies, such as LTE, Bluetooth, and IEEE 802.11be, as well as radiolocation applications, making it a promising choice for unmanned aerial vehicles conducting communication and radio monitoring missions.

Design consideration and recent developments in flexible, transparent and wearable antenna technology: A review

AbstractThe wearable technology and flexible electronics have been convoluted in modern technologies and many of applications especially insensors, biomedical, displays, solar panels, glasses, smart cities, integrated circuits, and wireless body area network (WBAN). They offer capability of mechanical deformation conditions mainly stretchable, bendable, foldable features and capable to severe environmental conditions. Nowadays, a device having lightweight, low‐profile, compact in size and flexible deployment on the system platforms is preferred. With the flexibility in the design of the antenna, they require flexible, robust, easy to wear, visually imperceptible, unobtrusiveness, and planar material for the realization. The characteristics of the wearable antenna may vary according to the material conductivity and their optical transparency, substrate selection and their thickness along with permittivity opted for and mechanical deformation behavior. Generally, the textile material is utilized to design the flexible wearable antenna due to material flexibility which can minimize the losses and enhance the antenna performance. Conversely, the visually imperceptible and flexible material is utilized to design transparent wearable antenna due to appropriate trade‐off between conductivity and optical transparency of the materials. For diverse WBAN applications, the flexible, transparent, and wearable antennas are utilized. This paper elaborates the comprehensive review and the state‐of‐the‐art research on the diverse categories of the wearable antennas based on the substrate characteristics such as flexibility and transparency. In addition, it provides the broad investigation of the flexible and transparent materials utilized to design wearable antennas and different tissue layers with their dielectric properties to develop the human multilayer phantom model.

Investigation of SAR reduction and gain enhancement using an all-textile antenna with metamaterial structure for wireless body area network applications

This work presents a wideband, low-profile, and flexible antenna that incorporates metamaterial (MTM) structures and textile materials. The antenna design is simulated using CST Microwave Studio, incorporating flexible textile elements such as a felt substrate and conductive fabric. The developed antenna's performance was examined numerically in free space and on a human body. The antenna with MTM technology operates in the ultra-wideband (UWB) with a bandwidth ranging from 3.86 to 13 GHz. It possesses a low profile with a thickness of 5.34 mm, making it suitable for applications in wireless body area networks (WBAN). Through the integration of metamaterial structures, the antenna's gain is enhanced, reaching 8.85 dBi compared to the initial gain of 5.34 dBi. Notably, the gain consistently exceeds 6 dBi across the entire UWB range, indicating focused power in a specific direction. For applications on the human body, specific absorption rate (SAR) values were calculated and found to be well within safety limits defined by European standards. This ensures minimal back radiation when the antenna is worn on the body, enhancing signal transmission range in WBAN applications.

Novel broadband circularly polarized pentagonal printed antenna design for wireless power transmission applications

<p>This paper provides a new conception for a microstrip patch antenna array that operates in a circularly polarized manner for wireless power transmission (WPT) at 2.45 GHz. The proposed conception combines four pentagonal patches and the defected ground structure (DGS) method. The antenna array with a dielectric constant of 4.4 and a tangential loss of 0.025 is printed on a FR4 where its thickness is about 1.58 mm. The developed design aims to optimize the antenna array performance. Th e main contribution, to the telecommunications and WPT fields, is to achieve a maximum energy transfer with low losses, while also ensuring adequate adaptation to the excitation port. To prove the effectiveness of this design, simulation results were obtai ned using computer simulation technology microwave studio (CST MWS) software and validated by another solver high - frequency structure simulator (HFSS). Simulation results are presented and compared with those obtained using existing conceptions in the lite rature. The proposed design has proven to be very effective in achieving the intended objectives, which makes this design very good for radiofrequency (RF) energy collection and its various applications to power a variety of devices without harming our pla net.</p>

Influence analysis of director’s elements on the circular Yagi disc antenna performance at 1.8 GHz

<span lang="EN-US">This paper aims to investigate and design a Yagi disc antenna with a variable number of director elements for Band 3 in <a name="_Hlk139294022"></a>fourth-generation long term evolution (4G LTE) mobile applications. The array technique was introduced by increasing the number of director elements to achieve superior results and better performance, such as higher gain and lower return loss. Initially, the simulated results of return loss and gain with one director element were -19.02 dB and 8.51 dBi, respectively. Then, by increasing the number of directors to three and five elements, the antenna’s performance improved significantly from -32.44 to -42.68 dB for return loss and from 8.51 to 11.17 dBi for gain, respectively. The simulated circular Yagi disc antenna provided a response in the range of 1.78 to 1.82 GHz. Therefore, a model was fabricated and tested to validate the antenna design. The measured results matched well with the simulated ones. By increasing the number of director elements, the measurement results of gain and return loss at a frequency of 1.8 GHz also showed improvement from 7.70 to 11.09 dBi and from -27.31 to -32.91 dB, respectively. Meanwhile, the measured antenna provided a wider bandwidth in the range of 1.72-1.82 GHz.</span>

Design and Simulation of Elliptical Shaped Microstrip Patch Antenna Using HFSS

Abstract: The elliptical patch antenna presents a comprehensive study on the design, fabrication, and performance analysis of an operating at 2.4 GHz, employing FR4 substrate material. The elliptical shape is chosen for its unique radiation characteristics and compact form factor, making it suitable for integration into modern wireless communication systems. The design process involves careful consideration of key parameters, including patch dimensions, feedline structure, and ground plane geometry. Advanced simulation tools, such as electromagnetic simulators, are employed to optimize the antenna's performance, achieving desirable characteristics such as low return loss and enhanced bandwidth. Utilizing FR4 as the substrate material offers several advantages, including costeffectiveness, ease of procurement, and compatibility with standard PCB manufacturing processes. The dielectric properties of FR4 are thoroughly analyzed and incorporated into the antenna design process to ensure accurate simulation results. The proposed elliptical patch antenna has promising applications in various wireless communication systems, including Wi-Fi, Bluetooth, and IoT devices, operating in the 2.4 GHz frequency band. Its compact size and robust performance make it a compelling choice for space-constrained and high-performance wireless communication applications. This contributes valuable insights into the design and optimization of patch antennas, particularly those using FR4 substrates, and serves as a foundation for the development of efficient and cost-effective wireless communication solutions in the 2.4 GHz spectrum.

Dual-polarized 8-port sub 6 GHz 5G MIMO diamond-ring slot antenna for smart phone and portable wireless applications.

This manuscript presents high performance dual polarized eight-element multiple input multiple output (MIMO) fifth generation (5G) smartphone antenna. The design consists of four dual-polarized microstrip diamond-ring slot antennas, positioned at corners of printed circuit board (PCB). Cheap Fr-4 dielectric with permittivity 4.3 and thickness of 1.6mm is used as substrate with overall dimension of 150 × 75 × 1.6 mm3. In mobile system due to limited space mutual coupling between nearby antenna elements is an issue that distort MIMO antenna performance. Defected ground structure is used to control coupling. The defected ground structure has advantages like ease of fabrication, compact size and high efficiency as compare to other techniques. Less than 30dB coupling is achieved for adjacent elements. The -10 dB impedance bandwidth of 700 MHz is achieved for all radiating elements ranging from 3.3 GHz to 4.1 GHz. The value is about 900MHz for -6dB. The proposed antenna offers good results in terms of fundamental antenna parameters like reflection coefficient, transmission coefficient, maximum gain, total efficiency. The antenna achieved average gain more than 3.8dBi and average radiation efficiency more than 80% for single dual polarized element. The antenna provides sufficient radiation coverage in all sides. The MIMO antenna characteristics like diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC) and channel capacity are calculated and found according to standards. Furthermore, effect of user on antenna performance in data-mode and talk-mode are studied. Proposed design is fabricated and tested in real time. The measured results shows that proposed design can be used in future smartphones applications. The design is compared with some of the existing work and found to be the best one in many parameters and can be used for commercial use.

Antenna Tracker System for Unmanned Aerial Vehicles: A Short Review

<p class="Abstract">Unmanned Aerial Vehicle (UAV) is a modern technology used to perform difficult and dangerous aerial missions that cannot be carried out by manned aerial vehicles. Ground Control Station (GCS) is a system that manages all the parameters of the UAV. GCS and UAV communicate using radio waves through telemetry, which functions to transmit and receive flight data. Antenna tracker is a device used to connect the GCS (Ground Control Station) and the UAV (Unmanned Aerial Vehicle). The antenna tracker works by performing tracking to direct the antenna towards the UAV. Nowadays, there are various forms of antennas used in telecommunication technology. Each type of antenna has its own radiation characteristics, some are directional, while others are more omnidirectional. Directional antennas are the right choice to be used with an antenna tracker. Generally, directional antennas have a narrow radiation range but a relatively long transmission distance. This paper provides a review of the state-of-the-art in antenna tracker technology for unmanned aerial vehicles (UAVs), with a focus on design, performance, and type of antenna. The study involved a literature search of various databases. The design approaches for antenna tracker systems range from simple single-axis trackers to sophisticated dual-axis trackers with pan-tilt mechanisms, and type of antenna such as helical were explored. The study concludes that antenna trackers have numerous applications in various industries, including military, agriculture, and surveying, and the demand for reliable and accurate antenna trackers is expected to continue to grow with the increasing popularity of UAVs. </p><p class="Abstract"> </p><p class="Abstract"> </p><p class="Keywords"> </p>

Towards phased array antenna operating in Ku-band for satellite communications

Satellite communication systems for mounting on vehicles are commonly based on phased array antennas with electronical beam steering. In this work we develop active metasurface-based receive-transmit antenna arrays for newly deployed satellite constellation system running in Ku-band. Both receive and transmit subarrays are based on patch-antenna elements driven in circular polarization using 90∘ hybrids. In both subarrays we optimized elements sizes and array period to have optimal ellipticity, gain, side lobe level. In electromagnetic simulations we achieved realized gain of 32.2 dBi for the Rx subarray and 33.4 dBi for the Tx subarray obtained in a broad scanning angle range from − 15∘ to + 45∘.

Selection of metallic liquid in sub-6 GHz antenna design for 6G networks

The rapid evolution of wireless communication systems toward 6G demands efficient antennas with the features of adaptability and versatility. Liquid antennas have gained significant research interest due to their unique features in realizing small, flexible, transparent, and reconfigurable antennas for promising applications in future wireless systems. In this paper, in order to find a suitable metallic liquid for effective antennas, we design and compare the performance of metallic liquid antennas using Mercury, gallium indium alloy (EGaIn), and Graphene metallic liquid in the sub-6 GHz frequency. The antenna is realized by the metallic liquid in a poly methyl methacrylate microfluidic channel over a liquid crystal polymer substrate at 5.6 GHz frequency. The performance of these metallic liquid antennas is analyzed by their electromagnetic and radiation performance. The Graphene-based metallic liquid antenna shows better electromagnetic performance in comparison to Mercury and EGaIn metallic liquid antennas.

A symmetric T-H shape wideband negative index metamaterial for 28-GHz millimeter-wave applications

One of the leading candidates for the next fifth generation of (5G) and body-centric wireless communications is millimeter-wave frequencies. In this study, a wideband tunable metamaterial (MTM) consisting of T-H shaped symmetric resonator is presented for body-centric applications operating in the millimeter-wave frequency band centered at 28 GHz. The characteristics of the proposed MTM are examined through wave propagation in both Z and X directions. It has a wide operating frequency range of 5.6 GHz for waves travelling along the Z-axis, with DNG characteristics at 26.2 GHz resonance frequency. However, it represents a negative epsilon metamaterial (ENG) range during X-axis wave propagation in the 25–29.4 GHz frequency range. The metamaterial is constructed on a Rogers (RT-5880) substrate and has a compact size, with overall dimensions of 0.420 λo × 0.420 λo. A proposed Y-shaped antenna is developed with a compact size of 1.36 λo × 1.82 λoto cover the 5G at 28 GHz. The single-Y-shaped antenna consists of aradiating patch, Rogers substrate, full ground plane, air bandgap (ABG), and array of DNG MTM.Thus, the array of MTM has been applied to validate the effect in the overall antenna performance such as gain which has been increased from 5.5 dBi to 8.5 dBi. The experimental, simulated results, and equivalent circuit model using Advanced Design Software (ADS) for validation functions showed that the completed results are comparable. The proposed mm-wave metamaterial is expected to be a good candidate for modern 5G wireless communication system components, especially to enhance the antenna gain and isolation. The proposed antenna loaded with MTM is a suitable contender for the upcoming 5G mm wave mobile handheld devices.

Six-element MIMO antenna structure with squared ring structure with multiband and high gain characteristics for C/X/Ku/K band applications

Using ring resonator structure, we have presented a structure of the six-element multiple input multiple output (MIMO) antenna structure. The proposed structure is numerically investigated and experimentally verified for antenna performance in the 1 to 25 GHz wideband frequency range. We have designed and verified the five antenna structure types, which consist of the various forms of ring/patch with different ground plane geometries. Various performance parameters like gain, directivity, reflections, and electric field distributions are analyzed for MIMO antennas. Essential performanceparameters observed for the MIMO antennas are also presented in this manuscript to identify the behaviour of the structure with different physical conditions. These parameters are also investigated for the identification of suitable ranges for the multi-channel transmission capability of the communication system. Return loss and Gain values are< −12 dB and ∼ 20 dBi achieved with ∼12 GHz of the operating bandwidth. Overall, the antenna offers minimum return loss values of −25 dB for the operating band of 19 to 25 GHz with anoperational bandwidth of 6 GHz. The designed antennas are tested using a ground patch and a rectangular patch in a scattered manner, and the obtained results are utilized in the Ultrawideband MIMO antenna applications. These antennas are also used in various band operations in satellite communication, including C/X/Ku/K bands.

A low profile perturbed CDRA with convex conformal ground plane excited by differential feed

A low profile, Convex Conformal Cylindrical Dielectric Resonator Antenna (CCCDRA) with perturbation excited by dual coaxial probes in Differential Feed Arrangement (DFA) with TM11δ and TM21δ modes being observed at 7.7 GHz, and 8.7 GHz respectively, is presented and examined in this paper. The radiation performance of the bent Cylindrical Dielectric Resonator Antenna (CDRA) is investigated and it can be observed that at the bent angle of φ1 = 24°, high broadside gain is obtained therefore it is chosen for the proposed design. Investigation on the DFA is carried out and it is observed that the differentially driven CDRA offers a low cross polarization as well as directional broadside radiation pattern. Wide impedance bandwidth is achieved by perturbing the CDRA in such a way so as to maximize the Surface Area to Volume (S/V) ratio, resulting in lowering the Q-factor. A high-gain of 9.6 dBi at 8 GHz for wideband wireless applications, featuring 30.5 % fractional bandwidth is achieved. Additionally, the proposed CDRA has a height of 0.16 λ0 with a low profile. The simulation results are found to be in good agreement with the experimental measurements performed on a fabricated prototype.

Broadband Continuous Transverse Stub (CTS) Array Antenna for High-Power Applications.

A continuous transverse stub (CTS) array antenna with broad bandwidth and high-power handling capacity is proposed in this paper. The technologies of multi-step impedance matching and T-shaped electromagnetic band-gap (EBG) loading are utilized, which improved the antenna operating frequency bandwidth. An H-plane lens horn is used to feed the CTS array. As a result, a good bandwidth capability of more than 32% is achieved, with a gain variation less than 3.0 dB. The measured sidelobe level (SLL) is below -18 dB in the entire frequency range. Moreover, the power handling capacity of the antenna is more than 80 MW and can reach the GW level after arraying, which indicates that this antenna has application potential in the high-power microwave (HPM) field.

Modeling of a Hexagonal Microstrip Patch Antenna for Breast Cancer Detection

Abstract Breast cancer is a global problem, and it is inevitable to detect cancerous cells at early stages. In recent years, microwave imaging (MWI) technology has been widely applied in biomedical applications for its non-ionizing radiation. Therefore, in this paper, a low profile hexagonal microstrip patch antenna has been proposed for the technology to detect breast cancer. This antenna has wide operating bandwidth of 13.5 GHz (6.6 GHz ¬to 20.1 GHz), and the return loss is as low as -50.83 dB at 8 GHz. To evaluate the antenna performances, the proposed antenna has been simulated in two different simulation software like HFSS and CST MWS. The antenna has achieved a maximum gain of 8.82 dBi with a quasi-omnidirectional radiation pattern. A three-layered human body mimicking breast phantom with different dielectric properties has been designed with and without tumor mimicking tissue. The difference between the dielectric properties of the tumor and the dielectric properties of different layers of breast phantom in the presence of external radiation field can inform the existence of tumor inside the breast phantom. An array of eight elements of proposed antenna is distributed around the breast phantom to detect the tumor with a minimum radius of 2 mm. Because of the low profile and compact in size (7.9 mm×11.4 mm), the proposed antenna is suitable for multi-static MWI technology for breast cancer detection at early stage.

Study on microwave heating energy supplement technology for gas hydrate reservoir

This study proposes a microwave heating energy supplement technology for gas hydrate reservoir. The microwave radiation simulation model of the leaky coaxial antenna is established by HFSS. Based on the simulation results of microwave antenna structure parameters on the radiation performance, the optimized shape, angle, length, width and fillet of the slot are rectangle, 80°, 38 mm, 12 mm and 2 mm, respectively. To compare the heating performance of microwave antenna before and after optimization, a microwave heating simulation model for hydrate reservoir is developed, which is validated by experimental results. The comparison results illustrate that, after microwave heating 10 h with the optimized antenna structure, the average temperature within a 1-m radius of natural gas hydrate reservoir increases to 10.613 °C, which is about 5.5 °C higher than that before the optimization. The aforementioned results suggest that the optimized microwave antenna structure significantly increases the temperature of the hydrate reservoir, providing the necessary energy to drive hydrate decomposition. The proposed microwave energy supplementation technique holds promise for advancing the efficient development of natural gas hydrates, the further investigation of effect of which on gas production within hydrate reservoirs is needed for future application.