Flexible Dual-Band Patch Antenna with Rubber Substrate for RF Energy Harvesting

Design of a Low-Cost Rectangular Microstrip Patch Antenna for Sub-6 GHz 5G Applications at 3.5 GHz

The increasing demand for compact, high-performance antennas capable of supporting multiple wireless communication standards has driven the development of multiband microstrip antennas. This research presents the design, simulation, and optimization of a multiband microstrip patch antenna operating at 2.4 GHz, 3.5 GHz, and 5.3 GHz, targeting applications in Wi-Fi and WLAN systems. The antenna structure is designed and analyzed using CST Microwave Studio, leveraging its full-wave 3D electromagnetic solver to evaluate key performance metrics including reflection coefficient (S11), gain, bandwidth, and radiation characteristics. To enhance the antenna's performance and reduce the design iteration cycle, support vector regression (SVR), a supervised machine learning technique, is employed. SVR models the nonlinear relationship between the antenna's geometric parameters and its performance outcomes, enabling efficient prediction and optimization. A dataset of 1844 samples is generated through parametric simulations in CST, and the SVR model—using a radial basis function kernel with C = 300, ε = 0.00000000025, and γ = 0.5—is trained to predict return loss and gain across the three target frequencies. The optimized antenna design achieves improved impedance matching, gain enhancement, and bandwidth control at all three frequency bands. Power transfer efficiency exceeds 96% in each band. The results demonstrate that the integration of SVR into the antenna design workflow provides a robust, data-driven approach to achieving multiband performance with high efficiency, making it suitable for next-generation wireless communication systems. Received: 11 August 2025 | Revised: 15 October 2025 | Accepted: 27 November 2025 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available from the corresponding author upon reasonable request. Author Contribution Statement Nejat Abdulwahid Hassen: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Data curation, Writing - original draft, Visualization, Supervision. Adomeas Asfaw Tafere: Conceptualization, Methodology, Software, Validation, Resources, Data curation,Writing - review & editing, Visualization,Supervision. Murad Ridwan Hassen: Conceptualization, Methodology, Software, Formal analysis, Investigation, Resources, Writing - original draft, Visualization, Supervision, Project administration. Tsega Asresa Mengistu: Conceptualization, Software, Validation, Resources, Writing - review & editing, Visualization, Supervision. Mekete Asmare Huluka: Conceptualization, Software, Validation, Resources, Writing - review & editing, Visualization, Supervision. Amsalu Tessema Adgeh: Conceptualization, Software, Formal analysis, Resources, Writing - review & editing, Visualization.

Performance analysis of microstrip patch antenna using a four-layered substrate of different materials

In this paper, a multi resonant MPA capable of operating satisfactorily in the frequency range of 2.39 GHz to 5.79 GHz have been proposed. The antenna has been designed using substrate of FR4 material having dielectric constant of 4.4 with a conducting radiating patch on the substrate and a conducting ground plane on the bottom side of substrate. The ground plane has been partially reduced to improve the antenna bandwidth. The antenna performance has been analyzed in terms of various antenna parameters such as return loss (dB), impedance bandwidth (GHz), gain (dB), directivity (dBi), Half power Beam width (Degree), current density and VSWR. The antenna has been designed and simulated using CST Microwave Studio (2010). The designed MPA is suitable to be used for Bluetooth, IMT, WLAN and WiMAX applications. The antenna has bandwidth of 3.40 GHz and VSWR of less than 2. The antenna has been successfully fabricated and tested. It has been observed that the practical results obtained by testing the fabricated antenna using Network analyzer E5071C closely matches with the theoretical results obtained by simulating the antenna design in CST MWS 2010.

This paper examines the role of a proper selection of a conducting material in the design of microstrip patch antenna. A microstrip patch antenna has three (3) main parts of ground, substrate and patch. The patch and the ground are made up of a conducting material. In this work, three (3) Rectangular Microstrip Patch Antennae (RMPA) were considered at 3.5 GHz resonant frequency for 5G applications with different conducting materials in order to determine the role of conducting material in designing a microstrip patch antenna. The antennae were designed, modelled and simulated using the same feeding methods, the same dimensions and the same materials with the exception of the conducting material. Copper annealed, iron and aluminium were used for the models of the antennae. It was found that the best conducting material was copper annealed, followed by aluminium then iron. Hence, the performance of a microstrip patch antenna depends on the type of conducting material used in its design among other factors. It is recommended that other conducting materials be explored to determine their role in ensuring effective design of the microstrip patch antenna.

This work suggests a new form of dual-band patch antenna for radio frequency identification applications (RFID) in the UHF band and the microwave band. A micro strip line whose power port is adapted to 50 ohms, located on a substrate type Epoxy FR-4, excites the patch. The design, modeling and analysis of simulation results were carried out under the electromagnetic simulator ADS. The first simulation results were obtained on a rectangular patch at 900 MHz. These results were improved by the introduction of notches and slots in the miniaturized structure of this antenna. The study of the proposed antenna has focused on the dimensions, the reflection coefficient, bandwidth and directivity.

This study presents a high-efficiency circular microstrip patch antenna designed for radio frequency identification (RFID) applications simulation results illustrate the performance of a circular microstrip patch antenna operating at 900 MHz. Microstrip antennas are renowned for their ability to meet the requirements of compact, lightweight designs, ensuring compatibility, and ease of integration. This research focuses on the development of a circular microstrip antenna, formed as a circular patch on a 0.035 mm thick FR-4 substrate. The design was realized using a substrate with a relative permittivity (εr) of 4.3, a loss tangent (tan δ) of 0.021 and a substrate height (h) of 1.6 mm. The antenna dimensions are small, measuring 58×45 mm, with a circular patch radius of 17 mm. The antenna operates over a frequency range from 0.5 GHz to 2 GHz. Key performance parameters include a return loss of -49.8 dB, a wide bandwidth of 150 MHz, a voltage standing wave ratio (VSWR) of 1.009, a gain of 2.161 dB, and a directivity of 2.200 dBi. Antenna design and simulation were carried out using computer simulation technology (CST) Studio Suite Software, specifically adapted to RFID applications.

Textile-based antennas are of great importance for wearable devices due to their flexible and compact design, which allows the creation of efficient wearable technologies. However, the use of flexible substrates in wearable antennas presents a number of challenges, including frequency shifts that occur during bending. A comprehensive analysis of the bending characteristics of flexible substrates is absent from the existing literature. The objective of this study is to analyze the performance of a Wi-Fi Microstrip Patch Antenna (MPA) designed to operate at 2.4 GHz using flexible substrates, such as leather, fleece, and felt, with a detailed examination of their bending characteristics. A bending analysis was conducted to measure the impact on performance metrics, such as return loss, bandwidth, gain, and Voltage Standing Wave Ratio (VSWR) under bending angles from 0° to 17°. The leather substrate exhibited minimal degradation in performance. The antenna demonstrated a return loss below -15 dB, a bandwidth exceeding 4%, a gain exceeding 5 dB, and a VSWR lower than 2.5 across all tested conditions. The leather substrate has emerged as a promising candidate for wearable Wi-Fi applications due to its ability to maintain stable performance metrics under bending conditions.

This paper presents the design of a novel dual-band coax-fed microstrip patch antenna (MPA), loaded with a fractal complementary split ring resonator (CSRR) for dual-band operation and partially defected ground structure (PDGS) for bandwidth enhancement. The proposed antenna operates in the WiMAX (Worldwide Interoperability for Microwave Access, 3.3–3.8 GHz) and entire WLAN (Wireless Local Area Network, 5.15–5.85 GHz) frequency bands with satisfactory far-field gain and efficiency.

This letter investigates the performance and requirements of High gain microstrip patch antennas for Sub-6 GHz 5G applications. Here the rectangular patch antenna is gradually modified with 3-different techniques: (i) Edge-cut single rectangular patch antenna (ii) Wheel shape slot loaded on the radiating patches (iii) Staircase-shape two element rectangular patch antenna array. This paper discussed 4 different rectangular microstrip patch antenna (RMPA) designs (Design - 1, 2, 3, 4) for Fifth generation communication system. The aim of the Wheel shape structure is to achieve wide bandwidth and antenna gain; Edge truncation technique helps to improve impedance matching and Staircase-shape structure helps to enhance bandwidth as well as achieves compactness of the antenna. All these antennas are convenient for Sub-6GHz 5G- NR band n79 (4.4 GHz to 5 GHz). All these structures are designed and simulated in ANSYS HFSS 2019 software.

Design of a high-gain dual-band LI-slotted microstrip patch antenna for 5G mobile communication systems

In this paper, a 4G and 5G microstrip patch antenna (MSPA) design and performance analysis for fifth-generation communication systems is presented. The antenna is designed using FR-4 substrate material with thickness of 1.1 mm, and dielectric constant (εr) of 4.3.This antenna is previewed to operate at 4.2 GHz for 4G and this will also be used with 28 GHz for 5G. Analysis was conducted using CST (Computer Simulation Technology) simulator. The simulation results are shown for these frequencies. This is explained including their respective bandwidths, HPBWs and gains. Tested antenna shows a good gain of 4.38dBi at 4G frequency of 5GHz and an excellent gain of 7.85dBi for 5G frequency at 27GHz. Results are enabling this antenna for 4G and 5G network mobile application.

This paper presents a microstrip patch antenna consisting of a rectangular patch with four circular slots incorporated into patch for C-Band Satellite Communication. The proposed antenna achieves an impedance bandwidth of 4.7 GHz (3.6 GHz to 8.3 GHz). Maximum reflection coefficient is achieved at 4.4 GHz i.e. −32 dB. Good reflection coefficient and radiation pattern characteristics are obtained in the frequency band of interest. The antenna has a planar rectangular geometry with microstrip line feed and symmetrical circular slots. The proposed antenna is designed on low cost FR-4 substrate. The antenna is designed and simulated using High Frequency Structural Simulator (HFSS). The several factors affecting the bandwidth and reflection coefficient of the microstrip antenna such as length of ground plane, substrate and radiating patch dimensions are discussed in the paper.

Recently, the increasing demands of 5G of higher data rates, and lower latency have been progressively investigated to cater the modernization and technology development. In order to achieve higher data rates, it is important to improve the bandwidth as well its gain. The antenna performance is crucial to determine the achievable bandwidth and gain. One of the parameters that influence the antenna performance is the thickness of the substrate. In this paper, a circular patch antenna is designed by using Rogers RT5880 of dielectric constant 2.2, and loss tangent 0.0009. The substrate thickness has been varied in order to investigate its effect to antenna performance i.e. return loss. The substrate thickness that has been investigated are 0.127 mm, 0.381 mm, 0.508 mm, 0.787 mm, and 1.575 mm, which are the standard thickness of Rogers RT5880. The simulation works are performed by CST Microwave Studio. The tasks are divided into two parts; i) the different substrates thickness are investigated while other parameters remain constant and ii) the radius of the circular patch of the antennas have been optimized in order to achieve the resonance frequency at 28 GHz based on the abovementioned substrate thickness used. The performance of the antenna is described in terms of its return loss, bandwidth, and gain. In (i), the results show that as the substrate thickness increases, the resonant frequency decreases under conditions of other fixed parameters value. The highest bandwidth is 1.17 GHz for substrate thickness of 0.508 mm while the highest gain is 7.52 dB for substrate thickness of 0.381 mm. For (ii), the highest bandwidth is 1.37 GHz for substrate thickness of 0.508 mm meanwhile the highest gain is 7.56 dB for substrate thickness of 0.381 mm at the resonant frequency of 28GHz.

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