Monopole Antenna Research Articles

A novel circular fractal ring UWB monopole antenna with dual band‐notched characteristics

AbstractThis paper presents a novel circular fractal ring monopole antenna for ultra‐wideband (UWB) hardware with dual band‐notched properties. The proposed antenna consists of four crescent‐shaped nested rings, a tapered feeding line at the front of the dielectric material, and a semicircular ground plane on the backside. In this design, the nested rings are used both as a radiation element and a band rejection element. The proposed antenna has a bandwidth of 9.03 GHz, which works efficiently in the range of 2.63 GHz–11.66 GHz with the dual notched bands of Worldwide Interoperability for Microwave Access (WiMAX) at 3.15 GHz–3.66 GHz and wireless local area network (WLAN) at 4.9 GHz–5.9 GHz, respectively. The antenna has a compact size of 20 mm × 30 mm × 1 mm (0.177 × 0.265 × 0.0084 λ0) and is implemented using a flame‐retardant type 4 (FR4) material. It has a maximum gain of approximately 4 dB in its operating range, and experimental results support the simulation predictions with high accuracy. The findings of this study imply that the designed antenna can be utilized in UWB applications.

Circularly polarized edge‐placed printed monopole antenna using theory of characteristic modes

AbstractThis article presents a method of using modal analysis to characterize the circular polarization (CP) performance of a printed monopole antenna. The radiator and feedline are positioned on the edge of the substrate and fed accordingly at the edge, and a modified ground plane is employed. The complete antenna without excitation is analyzed using characteristic mode theory to provide physical insight into its CP operation. The modal analysis proves that several nearly orthogonal modes can be generated at certain frequencies with orthogonal phase differences as well. The axial ratio (AR) corresponds to the modal analysis which proves the validity of the modal analysis. An axial ratio bandwidth from 3.1 to 6.2 GHz (66. 7%) is achieved within an S11 bandwidth of 2.6–11 GHz (123.5%). The proposed antenna is compact with stable radiation patterns, easy to design, and fabricate without inserting parasitic patches or inserting slots on the antenna.

Flexible and Small Textile Antenna for UWB Wireless Body Area Network

In this paper, a miniaturized textile microstrip antenna is proposed for wireless body area networks (WBAN). The ultra-wideband (UWB) antenna used a denim substrate to reduce the surface wave losses. The monopole antenna consists of a modified circular radiation patch and an asymmetric defected ground structure, which expands impedance bandwidth (BW) and improves the radiation patterns of the antenna with a small size of 20 × 30 × 1.4 mm3. An impedance BW of 110% (2.85–9.81 GHz) frequency boundaries was observed. Based on the measured results, a peak gain of 3.28 dBi was analyzed at 6 GHz. The SAR values were calculated to observe the radiation effects, and the SAR values obtained from the simulation at 4/6/8 GHz frequencies followed the FCC guideline. Compared to typical wearable miniaturized antennas, the antenna size is reduced by 62.5%. The proposed antenna has good performance and can be integrated on a peaked cap as a wearable antenna for indoor positioning systems.

Broad axial ratio bandwidth circularly polarized with wide angle coverage planar monopole antenna

A G-shaped circularly polarized broad axial ratio bandwidth (ARBW) and high gain monopole antenna is proposed. The proposed design is imprinted on low cost, lossy FR4 substrate with relative permittivity 4.4 and loss tangent 0.025. The physical dimension of the proposed antenna is 0.36λ0×0.39λ0×0.02λ0. The G-shaped patch is developed by modifying conventional monopole radiator to create circular polarization (CP) for strong horizontal and vertical current components. The stubs, L – shaped, and T-shaped parasitic strips (PSs) are loaded at the finest positions on the ground layer of the antenna to improve the performance of ARBW and gain. The achieved percentage impedance bandwidth (IBW), ARBW, angle coverage and gain are 106%, 97%, 102° (3 dB axial ratio beam width from −46° to + 56° in XZ – plane) at 4.26 GHz and 5 dBic respectively. The fabricated antenna is reliable for IEEE standard WLAN and broadband wireless communication system.

A monopole broadband circularly polarized antenna with coupled disc and folded microstrip stub lines

A broadband circularly polarized (CP) printed monopole antenna which fed by coplanar waveguide (CPW) is proposed in the paper. The structure of the novel antenna includes a quarter circular disc radiating monopole, a coupled circular patch, and a bent L-shaped microstrip stub line. The L-shaped microstrip stub line is used to widen the impedance bandwidth and generate a horizontal component of the electromagnetic wave. The adoption of the asymmetric ground coplanar waveguide structure with the single-feed technology and the coupled circular patch, simultaneously achieve wide impedance bandwidth and wide axial ratio (AR) bandwidth. The structure parameters and the surface current of the designed antenna are analysed. The simulation and the measurement are conducted, showing good characterizations of the designed antenna. The 10-dB impedance bandwidth is 7.57 GHz, the fractional bandwidth from 6.05 to 13.62 GHz is 76.9%, the 3-dB axial ratio bandwidth is 3.01 GHz, and the fractional bandwidth from 6.05 to 9.06 GHz is 39.8%. The antenna can generate right/left hand circularly polarized waves in the direction of ± z axis. The designed antenna has wide applications in the fields of Internet of Things (IoT), broadband dual-CP communication systems and polarization diversity systems, wireless personal area network and other advanced communication systems.

Wide-Band Antenna on Flexible and Thin Substrate for Wireless Systems

This paper presents the design of a flexible monopole antenna for wideband applications. The proposed antenna is printed on flexible substrate material having a dielectric constant of 3 for the design and fabrication of the proposed antenna. The antenna dimensions are 3.8 cm × 4.1 cm × 0.025 cm. The antenna characteristics are investigated not only in flat conditions but also under bending configuration. Both flat and bending configurations are operated at frequency bands from 2.4 GHz up to 10 GHz with S- parameters lower than − 10 dB. The antenna parameters such as gain, efficiency, and radiation patterns are studied for both configurations. A deep study for time-domain response is discussed to validate the performance of the proposed antenna to operate at a wide band with a highly correlated response.

Dual-Band Millimeter Wave 2 × 2 MIMO Slot Antenna with Low Mutual Coupling for 5G Networks

A dual-band 28/38 GHz multiple-input multiple-output (MIMO) two elements antenna for the next 5G network is proposed in this paper. The single element is composed of a slot monopole antenna loaded with stub and a small crescent with an entire size of 15 × 15 mm2. The two elements are added to compose the suggested configuration. One of the antennas is printed on the upper layer while the other is located on it's back of the substrate to improve the coupling between elements without using any decoupling structures. The innovative antenna of dual-band works at 28/38 GHz and is achieved by adjusting the stub length and the crescent radius. The introduced MIMO antenna system has been experimented and the results have the same compatible trace with the simulated outcomes. The proposed two ports MIMO achieved a reasonable gain that reaches 5.7 and 6.9 dBi in the 28/38 GHz bands, respectively. The proposed MIMO antenna performance is also analyzed and achieved the envelope correlation coefficient, a diversity gain, and channel capacity Loss of about 10–4, 10 dB, and less than 0.3 bit/s/Hz, respectively over the 28/38 GHz bands. Finally, from the simulated and measured outcomes, it can be confirmed that the suggested MIMO antenna system can be applied to 5G wireless telecommunication applications.

Elastomeric Textile Substrates to Design a Compact, Low-Profile AMC-Based Antenna for Medical and IoT Applications

A neoteric, compact, low-profile, wide-band elastomeric textile antenna for medical and IoT applications is presented. The design synthesis of flexible artificial magnetic conductor (AMC)-integrated antenna is done using stratum of textile and operates within 4.76–6.08 GHz covering the 5.8-GHz industrial, scientific, medical (ISM) and 5-GHz Wi-Fi band for IoT applications. The rectangular fed design operates in the high frequency band which is widened and optimized to operate in the lower 5-GHz band and the notch etched with the monopole’s edges, suppress the cross-polarization component. The suggested design features an impedance bandwidth of 24.4% with a high gain of 10.59 dBi and has a compact footprint of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.44\lambda _{0}\times $ </tex-math></inline-formula> 0.46 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}\times $ </tex-math></inline-formula> 0.0512 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> . Simulation and experimental studies provide evidence that in the case of structural deformities, such as bending and crumpling and also for human body loading, the suggested AMC-integrated antenna is stable and shows superior efficiency relative to the traditional monopole antenna. Thus, to a large extent, the antenna is stable to maintain its radiation properties. Furthermore, numerical analysis demonstrates maximum amount of the specific absorption rate (SAR) is 0.0832 W/Kg according to IEEE standard safety guidelines. The advantage of the suggested AMC-integrated antenna design is that it is resilient to moisture conditions and the enhancement in impedance bandwidth is achieved by simple cut edges in the radiator and the ground plane leading to a simple staircase design. In addition, the simulation and measurement results are consistent, thus confirming it to be a promising contender for sensing and applications in body-centric wireless communications and Internet of Things.

Monopole Cavity Resonator Antenna with AMC and Superstrate for 5G WiMAX Applications

For 5G and WiMAX applications, a coplanar waveguide (CPW)-fed monopole antenna sandwiched between an artificial magnetic conductor (AMC) and a superstrate is investigated. Because traditional planar antennas have low gains, they are unsuitable for a wide range of applications. This paper explores scientific strategies for increasing radiation gain in low-gain antennas such as planar monopoles. We use AMC in conjunction with superstrate to achieve a high gain antenna, with the monopole antenna serving as the primary radiator. However, a superstate like this demands the use of materials with high permittivity, and most of such materials are not readily available on the market. Even if such materials are available, they are mostly expensive and unsuitable for commercial systems. We investigate various superstrates and elaborate on which way these superstrates can be used interchangeably without compromising antenna performance. In the end, we fabricate one of these three superstrates. The antenna, which also employs AMC in tandem with the superstrate, has an impedance bandwidth ranging from 3.2 GHz to 3.75 GHz with 7 dBi gain, so it can be a viable candidate for 5G and WiMAX applications

Performance Analysis of an F-Shaped Antenna for Wireless Applications

The wide-band circularly polarised (CP) monopole antenna structure described in this article combines a defective ground plane with an f-shaped radiating monopole that is intended for impedance bandwidth and high axial ratio bandwidth (IBW). The faulty ground structure is etched as twin rectangular slots, an F-shaped slot, and a square slot with a corner cut off. The proposed antenna is 25 × 25 × 1.6 mm3 in total. The prototype of the optimised antenna’s far-field characteristics has been constructed, modelled, and experimentally confirmed. The simulated and measured return loss values are 3.19 to 7.4 GHz, with −32.48 dB and −38.42 dB, respectively. Axial ratio values are 4.37 to 7.22 GHz and 4.52 to 7.15 GHz, with an efficiency of 49.18% and 45.07%, respectively, for the simulated and observed bands. Gain levels in the whole CP band range from 2.8 to 3.3 dB. A continuous radiation efficiency of more than 90% is realised in the CP band. The suggested CP antenna has constant radiation qualities and is suitable for WLAN and WiMAX applications.

Surface current engineering enabled broadband monopole patch antenna with low profile

Antennas with broadband radiation and small-size are highly required in wireless communication system. The trade-off relation between bandwidth and size became a difficulty when it comes to miniaturized antenna design. A method of realizing antenna miniaturization and bandwidth enhancement at the same time is needed. Monopole antennas are the most common used one in the devices of Internet of Things, Internet of Vehicles, and wireless access points et al. In this paper, a wideband low-profile top-loaded patch monopole antenna based on surface current engineering is proposed. The topology combines a center-fed circular patch with inductive vias. The patch is designed with patterns, which consists of four concentric annular rings and some strips in radial direction. In this way, three resonances are generated, and the pattern is optimized to bring three resonances close to each other. The number of the strips is specially designed to bring three resonances close to each other. By loading the inductive vias on the outermost rings, connecting to the ground, the resonance at low frequencies can be enhanced, as a consequence of the optimized impedance matching. The field distribution is analyzed to verify the operation principle. A prototype is fabricated, and the measured results agree well with the simulated ones. The relative −10 dB bandwidth is 69% and the omnidirectional radiation pattern is stable in the operating band. The antenna achieves a rather wideband radiation while maintaining a low profile. The method of antenna miniaturization and bandwidth enhancement based on surface current engineering paves the way for antenna design in low-profile ultra-wideband applications.

Г-Shaped Asymmetrical Monopole Antenna on Truncated DGS For Multiband RF Energy Harvesting Applications

In today's world, through the advancement of technology, wireless communication has become an integral part of our lives with the utilization of versatile electronic devices such as cell phones, tablets, and computers that contain wireless communication modules. The idea of utilizing different frequencies and power of RF signals in the environment has led to the concept of harvesting RF signals to produce DC output voltage. In this paper, a printed multiband monopole antenna is presented. The proposed antenna is composed of two Г-shaped asymmetrically positioned feeding lines which are located on slotted truncated ground plane with three stubs loaded on both ground plane sides. The antenna design covers the frequently used frequencies for electronic device communication, such as GSM 1800, UMTS 2100, WLAN 2450 and LTE 2600 With the numerically computed gain values of 3.89dBi at 1.8GHz, 4.51dBi at 2.1GHz, 5.02dBi at 2.45GHz, and 5.03dBi at 2.6GHz, respectively. The proposed antenna design has permissible gain values to be used for RF energy harvesting applications.

Millimeter-Wave Dual-Band MIMO Antennas for 5G Wireless Applications

This paper suggests a dual-band 28/38 GHz four-element MIMO array based on dual-mode planar monopole antennas for 5G wireless applications. The design structure contains four planar monopole antennas; located at the corners on a 20 × 20-mm2 size Rogers RO4003 substrate with a dielectric constant of 3.55. The proposed planar monopole antenna has the shape of a crescent. In order to achieve the desired behavior and perfor mance, we engraved two rectangular slots on both sides and also added a notch at the bottom. In addition, we used a partial ground plane to enhance the isolation. Significant isolation (> − 23 dB) is achieved between antenna elements by employing spatial and polarization diversity techniques. To validate the design concept, a prototype of the four-element MIMO array is designed, fabricated, and measured. The experimental results show that the proposed antenna can cover the 27.25–29 GHz and 34.5–41 GHz bands with good isolation and high efficiency. Furthermore, the radiation pattern, the realized gain, and the channel capacity are also studied. According to the reached results, the proposed MIMO antenna may be a suitable application-oriented design for 5G MIMO applications at the millimeter-wave range.

A Compact Share-Aperture Antenna With Pattern/Polarization Diversity for 5G Sub-6G Applications

A compact share-aperture antenna with pattern/polarization diversity is presented for fifth-generation (5G) Sub-6G applications in this brief. The even and odd modes of the coplanar waveguide (CPW) constructions, respectively, activate the monopole and Vivaldi antennas, which make up the suggested antenna. Additionally, gain is increased while back radiation and edge effects are reduced by using the defected ground structure (DGS). By varying the excitation amplitude and phase of the two ports, the proposed antenna can operate in four different modes: mode 1 (omnidirectional), mode 2 (broadside), mode 3 (left titled) and mode 4 (right titled). The entire dimension is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.667\mathbf {\mathrm {\lambda }} _{0} \mathbf {\times } 0.500\mathbf {\mathrm {\lambda }} _{0} \mathbf {\times } 0.007\mathbf {\mathrm {\lambda }} _{0}$ </tex-math></inline-formula> (where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathbf {\mathrm {\lambda }} _{0}$ </tex-math></inline-formula> is the free space wavelength at 2 GHz). The four modes collectively span a 100% −10 dB impedance bandwidth (2-6 GHz). In the common bandwidth (2-6 GHz, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\unicode{0x007C}\text{S}_{11}\,\,\unicode{0x007C}\mathbf { &lt; }-$ </tex-math></inline-formula> 10 dB), the isolation between the two ports is more than 25 dB. The suggested design has been produced and tested, and the measured results match the simulations well.

A Dual-Band Antenna for LTE/mmWave Mobile Terminal Applications

In this communication, a dual-band antenna is proposed, which integrates a millimeter-wave (MMW) substrate-integrated dielectric resonator antenna (SIDRA) beam-steerable array and long-term evolution (LTE) folded monopole antenna (FMA). The SIDRA, which is a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times4$ </tex-math></inline-formula> tightly arranged DRA array with zero edge-to-edge spacing, is developed in the clearance area of the FMA. Hence, the two antennas not only share the same substrate but also share the same aperture. The performance of FMA will not deteriorate by properly locating the SIDRA array. An antenna prototype was fabricated and measured, and the rationality of the design was verified. The LTE FMA can cover the band of 1.78–2.62 GHz (38.2%) and achieve a peak gain of 3.9 dBi, while the MMW array can cover the band of 26.4–29.8 GHz (12.2%) and achieve a peak gain of 10 dBi. The MMW array can support beam-steering angles of ±45°. The high space utilization of the proposed design strategy makes the dual-band antenna suitable for the fifth-generation (5G) mobile terminal applications.

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

Low specific absorption rate quad-port multiple-input-multiple-output limber antenna integrated with flexible frequency selective surface for WBAN applications

This paper presents the design and analysis of a multiple-input-multiple-output (MIMO) textile antenna for wireless body area network (WBAN) applications. The MIMO antenna is comprised of four identical modified rhombus-shaped monopole antenna elements of size of 0.57, where is the wavelength calculated at the lowest operating frequency. The antenna is backed by a 6 frequency selective surface (FSS) of dimensions of 0.84 to improve gain and to reduce specific absorption rate (SAR). The antenna has an impedance bandwidth (S 11 ⩽ −10 dB) of 8.8 GHz (2.8–11.6 GHz) and isolation of >19 dB between the resonating elements. In order to assess the MIMO antenna’s flexibility, the bending analysis is performed for various bending radii. The obtained diversity metrics are: envelope correlation coefficient <0.5 dB, diversity gain <10 dB, channel capacity loss <0.4 bits s−1 Hz−1, and total active reflection coefficient <−10 dB. The performance of the antenna with and without FSS is investigated for gain enhancement and SAR reduction. With the help of FSS, the antenna gain is increased to 8.44 dBi, and the SAR reduced from 6.99 Watt kg−1 to 0.0273 Watt kg−1. The FSS achieves the highest efficiency of 96%. The designed antenna is suitable for smart textile applications due to its low SAR, high gain, and wider impedance bandwidth.

Split–ring resonator loaded pentagon antenna for super wide band communications

This work describes the designof an SRR-loaded pentagon monopole antenna for super wideband (SWB) applications on Rogers RT/Duroid 5880 dielectric material with dielectric constant of 2.2, and a dielectric loss tangent of 0.0009. The pentagon patch radiator is fed with a 50 Ω transmission line placed on the dielectric size of 16 mm × 14 mm × 0.787 mm. In this paper, SRR is etched from the radiating element, and partial ground is added to improve the performance characteristics. The proposed antenna has a bandwidth ratio (BR) of 185.38 and an impedance bandwidth (IBW) of 66.38 GHz at a reflection coefficient of −10 dB. It has a fractional bandwidth (FBW) of 197.85% and a bandwidth dimension ratio (BDR) of 19,786 dB, with a peak gain of 6.2 dB. The proposed antenna covers microwave applications, which cover the following spectrums: L: 1–2 GHz, S: 2–4 GHz, C: 4–8 GHz, X: 8–12 GHz, Ku: 12–18 GHz, K: 18–26.5 GHz, Ka: 26.5–40 GHz, and limited millimetre wave frequencies up to 70 GHz.

Circularly Polarized Textile Sensors for Microwave-Based Smart Bra Monitoring System

This paper presents a conformal and biodegradable circularly polarized microwave sensor (CPMS) that can be utilized in several medical applications. The proposed textile sensor can be implemented in a Smart Bra system for breast cancer detection (BCD) and a wireless body area network (WBAN). The proposed sensor is composed of a wideband circularly polarized (CP) textile-based monopole antenna with an overall size of 33.5 × 33.5 mm2 (0.2 λo × 0.2 λo) and CPW feed line. The radiating element and ground are fabricated using silver conductive fabric and stitched to a cotton substrate of thickness 2 mm. In the proposed design, a slot is etched in the radiating element to extend bandwidth from 1.8 to 8 GHz at |S11| ≤ -10 dB. It realizes a circularly polarized output with AR ≤ 3 dB operation band from 1.8 to 4 GHz and an average gain of 6 dBi. The proposed CPMS's performance is studied both off-body (air) and on-body in proximity to breast models with and without tumors using near-field microwave imaging. Moreover, the axial ratio is recorded as a feature for a circularly polarized antenna and adds another degree of freedom for cancer detection and data analysis. It assists in detecting tumors in the breast by analyzing the magnitude of the electric field components in vertical and horizontal directions. Finally, the radiation properties are recorded, as well as the specific absorption rate (SAR), to ensure safe operation. The proposed CPMS covers a bandwidth of 1.8-8 GHz with SAR values following the 1 g and 10 g standards. The proposed work demonstrates the feasibility of using textile antennas in wearables, microwave sensing systems, and wireless body area networks (WBANs).

WEARABLE ANTENNA DUAL BAND WITH ELECTROMAGNETIC BAND GAP (EBG) STRUCTURE FOR HEALTH APPLICATIONS

Telemedicine can solve several issues in the healthcare system. The wearable antenna works with the Industrial, Scientific, and Medical (ISM) band for wireless body area network (WBAN) communications. Wearable antennas are lightweight, easy to make, and so on. This antenna application's bandwidth is limited by the thin substrate. This research will create a wearable planar monopole antenna with a circular patch that can operate at 2,4 and 5,8 GHz. Antenna without the UC-EBG structure and antenna with the UC-EBG structure were tested. The simulation results without UC-EBG show that the return loss is -14.629 dB and -28,639 dB, the VSWR is 1,456 and 1,077, the bandwidth is 4988 MHz, and the gain is 2,517 dBi and 4,270 dBi. The simulation results with the addition of UC-EBG show that the return loss is -13,835 dB and -17,46 dB, the VSWR is 1,511 and 1,309, the bandwidth is 1480 MHz and 2320 MHz, and the gain is 2,869 dBi and 5,208 dBi. The measurement results with UC-EBG show that the return loss is -13,134 dB and -18,421 dB, the VSWR is 1,566 and 1,273, the bandwidth is 1080 MHz and 960 MHz, and the gain is 2,198 dBi and 4,98 dBi.