Design of Multiband Antennas for Wireless Communication

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.

In modern world, communication devices need to be operated for more than one frequency bands. Lot of research works were carried out in the field of multiband antennas. The one major concern in the design of multiband patch antenna are the gain and bandwidth. Both gain and bandwidth of the multi band antenna can be improved for the better performance. In this paper a triangular multiband antenna is designed and the gain of the antenna is enhanced by the blend of reactive impedance surface and Frequency selective surface. The proposed antenna resonates 3.4 GHz, 4.2 GHz, 6.75 GHz,7.1 GHz, 7.5 GHz and 9.3 GHz with a better return loss and gain.

IntroductionThe popularity of mobile communication systems has increased remarkably during the last decade and the market demand still continues to increase.As a fundamental part of these systems, antenna is one of the most important design issues in modern mobile communication units.Although there are several similar definitions, an antenna can be mainly described as a device, which transforms the electromagnetic waves in an antenna to radiating waves in an unbounded medium such as air in transmitting mode and vice versa in receiving mode.Because antennas are dependent on frequency, they are designed to operate for certain frequency bands.The rapid growth of mobile communication systems has forced to the use of novel antennas for base and mobile station applications (mobile phone, notebook computer, personal digital assistants (PDA), etc.).Earlier, mobile systems were designed to operate for one of the frequency bands of 2G (second generation) systems, which are Digital Cellular System (DCS), Personal Communications Service (PCS) and Global System for Mobile Communications (GSM) networks.Currently, many mobile communication systems use several frequency bands such as GSM 900/1800/1900 bands (890-960 MHz and 1710-1990 MHz); Universal Mobile Telecommunication Systems (UMTS) and UMTS 3G expansion bands (1900-2200 MHz and 2500-2700 MHz); and Wi-Fi (Wireless Fidelity)/Wireless Local Area Networks (WLAN) bands (2400-2500 MHz and 5100-5800 MHz) where the list of frequently used frequency bands is given in Table 1 ( Best, 2008).Conventionally, because a single antenna can not operate at all of these frequency bands of mobile communication, multiple different antennas covering these bands separately should be used.However, usage of many antennas is usually limited by the volume and cost constraints of the applications.Therefore, multiband and wideband antennas are essential to provide multifunctional operations for mobile communication.A multiband antenna in a mobile communication system can be defined as the antenna operating at distinct frequency bands, but not at the intermediate frequencies between bands.For example, a triple band antenna for GSM 900/1800/1900 bands can cover the frequency bands 890-960 MHz and 1710-1990 MHz (Ali et al., 2003); however, it does not operate properly at the frequencies such as 1200 MHz or 2500 MHz.On the other hand, a wideband antenna operates at every frequency points within a given frequency band.For example, a wideband antenna covering UMTS, extended UMTS and WLAN 2400 bands functions at every frequency points www.intechopen.com

The following study details the design and analysis of a multi-band microstrip patch antenna optimized for compactness and intended for C and X-band wireless applications. As the need for high-performance communication systems, particularly in satellite, radar, and high-speed wireless networks, is on the rise, multi-band antennas are important. The antenna that has been proposed is intended to work effectively at several frequencies of resonance in the C-band and X-band ranges, which makes it ideal for use in fields of study including satellite communications, weather monitoring, and air-based radar systems. The antenna is mounted on a commercially available FR4 substrate that is flame retardant and has dimensions of 25 × 25 × 1.3 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. The antenna resonates at 6.36 GHz, 10.17 GHz, and 11.58 GHz having good return loss values of –39.97 dB, –24.59 dB, and –24.48 dB respectively. All the simulations and designs have been performed with CST Microwave Studio software showing a satisfactory S-parameter performance, gain, and radiation efficiency in all the operating bands.

SummaryA novel multiband pinwheel fractal antenna with monopole configuration is proposed. The pinwheel fractal antenna has been fabricated on a commercially available FR4 substrate with a thickness of 1.6 mm. This paper proposes a novel pinwheel antenna with a 50% reduction in the dimension of width with a reduced level of return loss. The proposed antenna has multiband characteristics covering the bands of GSM (900 MHz), DCS (1710 GHz), PCS (1900 MHz), UMTS (1920 MHz), and WLAN (2.4–5.9 GHz) applications. The projected antenna resonates at multiple frequencies with acceptable antenna gain and directivity. The proposed antenna design is optimized by particle swarm optimization (PSO) algorithm. The parametric studies and the design rule for the proposed fractal have been reported. The prototypes of the proposed multiband antenna have been demonstrated. The measured and simulated results ensure the multi‐resonance characteristics and authorize the projected design method and gratify the necessities of handheld wireless communication systems. The performance analysis proves that the proposed novel pinwheel antenna provides reduced return loss.

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

In the current era, the need of wireless technologies are raising enormously day by day where small in size, low in weight, easy installations are most important. Patch antenna offers effective low profile designs for a broad range of wireless applications. They are very efficient for high frequency applications with light in weight and in expensive to fabricate. In this paper, various shapes of patch antenna like S-slot, H-shape, pyramidal and square shape were designed and the parameters were analyzed using Advanced Design System (ADS) environment. Based on the return loss and power radiated, the spanner shaped antenna is chosen as the optimum design. Further the designed antenna was optimized by changing the dimensions, thickness and material of substrate, dielectric constant and the feed position. The optimized antenna was tested in ADS which achieved a return loss of -25dB at 9.4 GHz and radiated power of about 0.0123 watts. Then the designed antenna is fabricated using FR-4 substrate which has an advantage of low cost and the fabricated antenna was tested for the same parameters using Network Analyzer. The return loss was found to be -22dB at 9.4 GHz and the radiated power was 0.031 watts which is better than the simulated results. The designed antenna can further extended for the use in Wi-Max applications.

The modern wireless communication desires high gain, wide bandwidth and minimal size antennas that are efficient to provide improved performance over a wide range of frequency spectrum. This requirement leads to the design of microstrip patch antenna. This paper presents the design of compact 1X2 microstrip patch antenna array which uses the corporate feed technique for excitation. The proposed antenna is designed on FR-4 substrate with dielectric constant 4.4 and thickness 1.6mm. Dielectric constant and parameters like Return Loss, Gain and Radiation pattern are calculated using high frequency simulation software. The fabricated antennas results are to be compared with Simulation results. The antenna has been designed for the range 2.4 GHz. Keywords: Microstrip antenna, corporate feed, FR-4 substrate, Microstrip antenna array

Offset-fed complementary split ring resonators loaded monopole antenna for multiband operations

This paper presents a design of triangular microstrip patch antenna with varying substrate heights. The operating frequency used is in the range 1–3 GHz for wireless communication systems. Microstrip patch antenna with triangular shape is fabricated on FR-4 substrate which has a relative permittivity of 4.4 and mounted at a height above ground plane. Important parameters of antenna like return loss, input impedance, antenna gain, and VSWR are observed and comparison is done among the different antenna widths.

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.

This research work presents dual-band rectangular microstrip patch antennas resonating at X, Ku, and K-bands for wireless satellite communications. Three antenna structures with different configuration techniques are positioned on the surface of the patch mounted upon a grounded substrate made of Rogers RT Duroid 5880. The radiation mechanism of the suggested antenna design is studied, compared, and analyzed with its contemporary structures. Their radiation performance is evaluated in terms of reflection coefficient, −10 dB bandwidth, VSWR, input impedance, radiation efficiency, gain and found satisfactory. These structures find their application in wireless satellite communications.

In this communication, artificial neural networks are used to estimate the initial structure of a multiband planar antenna. The neural networks are trained on a set of selected normalized multiband antennas characterized by time-efficient modal analysis with limited accuracy. Using the Deep Learning Toolbox in Matlab, several types of neural networks have been created and trained on the sample planar multiband antennas. In the neural network learning process, suitable network types were selected for the design of these antennas. The trained networks, depending on the desired operating bands, will select the appropriate antenna geometry. This is further optimized using Newton’s method in HFSS. The use of the neural pre-design concept speeds up and simplifies the design of multiband planar antennas. The findings presented in this paper will be used to refine and accelerate the design of planar multiband antennas.

In this letter, a C-band compact wideband bandpass filter (BPF) with high selectivity and improved return loss (RL) is proposed. Two pairs of short-circuited stubs are employed on a transmission-line model to generate three transmission poles and two transmission zeros (TZs), where the odd- and even-mode analysis is used to analyze the resonant frequencies of the BPF. By applying the transversal signal-interference technique, two additional TZs can be generated in the upper and lower stopbands, respectively. The measured results show that the 3-dB fractional bandwidth is 62.8% at the center frequency of 5 GHz. The RL and the insertion loss within the passband are better than 22 and 0.6 dB, respectively. Moreover, the roll-off rate is up to 100 dB/GHz.

In this paper, a compact planar patch antenna is proposed for multi-band wireless communication applications. The antenna is consists of an inverted F-shaped radiating element and a modified F-shaped ground and is imprinted on the both side of a low cost FR4 substrate material. To excite the resonant modes at multiple operating bands, two inverted L-shaped resonating elements are added respectively to the patch and ground plane and thus the antenna is able to achieve eight frequency bands of 835 – 872 MHz, 1.476 – 1.566 GHz, 2.185 – 2.280 GHz, 3.080 – 3.256 GHz, 3.618 – 3.680 GHz, 4.215 – 4.335 GHz, 4.582 – 4.692 GHz and 5.405 – 5.925 GHz bands.