Monopole Antenna Research Articles

A low-profile ultra-wideband hexagonal-patch antenna for UAV-based applications

ABSTRACT A compact, low-profile, and ultra-wideband antenna is always desirable for airborne Unmanned Aerial Vehicles (UAV) applications. In this paper, an ultra-wideband monopole antenna is presented with the benefit of a compact and low-profile design structure. The antenna design enables efficient communication without interfering with the UAV’s other components. The antenna is designed using a slotted-hexagonal-patch fed from a co-planar microstrip feed. The bow-tie-shaped slot along with a few other rectangular-shaped parasitic slots are loaded in the hexagonal patch for bandwidth enhancement. The coplanar feed with top ground offers minimum interference with the UAV structure. The non-conducting bottom plane allows seamless integration without causing any interference to the antenna. An equivalent circuit model (ECM) of the proposed antenna is also developed. The antenna structure is fabricated and the measured results are validated. A good agreement between the measured and simulated results is observed. The antenna covers an ultra-wideband ranging from 3 GHz to 13.5 GHz with a maximum gain of 4.0dBi. The size of the antenna is 0.24λ0 ×0.29λ0 ×0.01λ0. The developed antenna, therefore, demonstrates that it is a strong contender for ultra-wideband UAV-based applications.

Design of MIMO Antennas With DRAs and a Dual-Function Decoupling/Radiating Monopole Antenna

Design of MIMO Antennas With DRAs and a Dual-Function Decoupling/Radiating Monopole Antenna

A compound reconfigurable electronically switched parasitic monopole antenna for sub 6 GHz wireless and vehicular applications

In this paper, a compound reconfigurable electronically switched parasitic monopole antenna is reported for sub-6 GHz (n77/n78 bands) wireless standards and vehicular communication. The antenna comprises a half-hexagonal-shaped radiating element and two inverted L-shaped parasitic stubs. These stubs are connected through two PIN diodes, allowing for control over frequency. An additional pair of PIN diodes incorporates analogous parasitic stubs into the ground plane to facilitate pattern tilting and polarization. By switching these PIN diodes across seven operating states (OS), the antenna structure could resonate in a single band, spanning 4.5–5.8 GHz (sub-6 GHz higher band), with an omnidirectional pattern specific to OS1. In OS2 and OS3, the antenna resonates in a single band within the range of 4.1–5.7 GHz, featuring beam tilting with linear polarization. In OS4 and OS5, the structure has two bands: one covers 3.3–4.2 GHz (5G-n77 band) with linear polarization, and the other covers 5.1–6.1 GHz (5G WLAN band) with right-hand circular polarization (RHCP) in OS5 and left-hand circular polarization (LHCP) in OS4 with an axial ratio bandwidth of 14.5 %, including pattern tilting within the range of ± 340. Finally, in the OS6 and OS7 structure introduce dual bands of 3.3–3.8 GHz (5G–n78 band) and 4.8–5.8 GHz (sub-6 GHz higher band). Both bands feature LHCP/RHCP with an axial ratio bandwidth of 8.57 % for the lower resonant band and 7.4 % for the higher resonant band. Additionally, it incorporates radiation pattern reconfiguration capabilities. The structure is printed on an FR-4 substrate and measures various associated parameters. The experimental results closely match the simulated results.

Electrically Small, Near-Field Resonant Parasitic Monopole Antenna With Large Gain-Bandwidth Product and Harmonic Modes Migration

Electrically Small, Near-Field Resonant Parasitic Monopole Antenna With Large Gain-Bandwidth Product and Harmonic Modes Migration

Design of a Compact and Wideband Printed Monopole Antenna With Stable Omnidirectional Radiation Patterns

Design of a Compact and Wideband Printed Monopole Antenna With Stable Omnidirectional Radiation Patterns

Design of UWB Wearable Conformal Antenna for Body Area Networks

In this paper, a wearable ultra-wideband (UWB) micro-strip antenna is designed to meet the demand for Wireless Body Area Network (WBAN). This is a wearable textile antenna, which was formed on a jeans fabric substrate to reduce surface-wave losses. The single-fed circular strip monopole antenna provides good impedance matching over the entire UWB frequency range of 2.9∼10.6 GHz. The dielectric constant εr 2.2, and the loss tangent tan δ 0.04 of the jean substrates are measured by using the coaxial ring method. The proposed antenna consists of an improved circular radiation patch with the defective ground structure to expand the frequency band of the antenna and improve the radiation characteristics of the antenna with small dimensions of 20 × 30 × 1.4 mm3. In addition, structural deformation of the proposed antenna is performed to analyze the flexibility of the proposed antenna. The simulated SAR values follow the FCC limit, making it most suitable for wearable applications. Key Words: Antenna, S-Parameters, Far Field Directivity, Applications of Antenna, HFSS.

Improvement in notch band characteristics of a hexagonal super wideband antenna by interfering back radiation out of phase with front radiation using frequency selective surface

SummaryA band‐notched super wideband (SWB) planar monopole antenna with improved notch characteristics is proposed in this article. A hexagonal SWB antenna operating in the frequency range from 3.04 to 36 GHz is initially designed on Arlon substrate. The hexagonal patch is then loaded with optimum sized U‐shaped slot to eliminate WLAN band (5.15–5.85 GHz). The notch band's characteristics are further improved by incorporating a frequency selective surface (FSS) of a square array at a specific distance below the antenna to introduce a phase delay of 180° between the back radiation reflected by the FSS with the front radiation at the notched frequency. Improvement of notch band gain, efficiency, and antenna front‐to‐back ratio (FBR) are studied. The antenna without embedding an FSS exhibits working spectrum from 3.1 to 33.6 GHz with notch frequency gain of −2.6 dBi and efficiency 53%. The inclusion of an FSS layer at 25.2 mm behind the antenna results in notch frequency gain of −7.6 dBi with an efficiency of 23%. FBR improvement of about 16 dB is achieved at 8 GHz, and FBR is reduced by about 5 dB at the notch frequency. 169% fractional bandwidth with bandwidth dimension ratio (BDR) of 1622 is achieved in this proposed FSS integrated antenna. The inclusion of FSS to improve the band elimination performance represents the novelty of this proposal. The data are validated by electromagnetic simulation and physical measurement techniques.

A Novel Dual-Band Circularly Polarized Wearable Antenna.

A circularly polarized wearable antenna operating in the 2.45/5.8 GHz ISM dual bands is proposed, which consists of a coplanar waveguide-fed rectangular monopole antenna and two parasitic branches. The monopole rectangular radiation patch can generate 2.45 and 7 GHz frequency bands and has linear polarization characteristics. By adding L-shaped parasitic branches and L-like grounded branches on both sides of the monopole, the 7 GHz operating frequency band can be moved to the 5.8 GHz frequency band, and circular polarization characteristics can be achieved in both the 2.45 and 5.8 GHz frequency bands. The size of the antenna is 48.7 mm × 42.1 mm × 1.016 mm. The simulated -10 dB impedance bandwidths of the antenna are 1.8-2.66 GHz and 5.48-6.98 GHz, respectively. The 3 dB axial ratio bandwidths are 2.34-2.67 GHz and 5.58-6.39 GHz, respectively, and it has dual-band circular polarization characteristics. In addition, the radiation characteristics of the antenna and its safety performance near the human body were analyzed. The antenna prototype has been constructed, and the measurement and simulation results have good consistency. The proposed antenna is suitable for application in wearable devices.

Performance enhancement of Vivaldi-shaped planar UWB antenna using a single-layer FSS reflector

This work proposes the design of a frequency-selective surface (FSS)-based planar monopole antenna for ultra-wideband (UWB) communication applications. The UWB response is observed by integrating a Vivaldi-shaped slot and by introducing a stepped-like pattern on the bottom edges of the radiating patch, while the back side is composed of a partial ground plane. This configuration results in a broad impedance bandwidth spanning from 3.11 to 20 GHz. For radiation performance enhancement of the proposed antenna, a single-layer UWB FSS reflector is placed beneath the antenna element at an optimized distance. The proposed FSS reflector employs a 3 × 3 array of fractal structure with a unit cell size of 12.25 × 12.25 mm2. The designed FSS reflector exhibits a linear phase response over a frequency range of 3.28 to 14 GHz, with a stop-band transmission coefficient less than -10 dB. The incorporation of the FSS reflector results in an increased gain, elevating it from 1 to 4 dBi at low-band frequencies, while at mid-band frequencies, the gain is increased from 1 to 6 dBi. The structural configuration of the proposed antenna yields directional far-field patterns, making it well-suited for UWB radar applications.

Efficient Microstrip Monopole Antenna Design for Multi Technology Wireless Applications

The demand for compact, efficient antennas capable of supporting multiple wireless communication standards continues to drive innovation in the field. In this paper, we present a novel approach to designing microstrip monopole antennas, leveraging a unique set of design equations to achieve superior performance across 3GHz and 6GHz frequency bands. Additionally, we explore the development of array antennas by combining two microstrip monopoles, offering enhanced gain and radiation characteristics compared to single-element designs. By varying array substrate material, we aim to further optimize performance for applications such as WiFi, LTE, and WiMax. Keywords- Microstrip antenna, broadband monopole antenna, dual band monopole antenna, compact monopole.

Design and analysis of a small size triple band printed antenna for 3G/4G/5G/future 5.8G IoT applications

SummaryThis paper presents a compact (20 × 20 × 1.59 mm3), (0.34λg × 0.34λg × 0.01λg at 2.4 GHz) triple band monopole antenna for Internet of Things (IoT) applications. The geometry of the antenna consists of (i) U‐shape monopole with feed line, (ii) stubs, and (iii) modified ground to achieve three independent operating bands ranging from (i) 2.4–2.48 GHz for industrial, scientific, and medical (ISM)/3G; (ii) 3.4–3.6 GHz for 4G/5G; and (iii) 5.725–5.825 GHz for 5.8G Wi‐Fi/extended 5G. Various parameters, input impedance, and current distribution of the proposed structure are carried out to investigate the effects of stub, ground plane and analyze the radiation. The measured result covers the three individual bands in range of 2.38–2.48 GHz, 3.41–3.61 GHz, and 5.76–6.04 GHz, respectively, and exhibits stable omnidirectional radiation patterns, acceptable antenna gain, and efficiency in the operating bands. The experimental result of the fabricated antenna closely matches with the simulated result. Therefore, satisfactory result ensures its ability to work for 3G/4G/5G/extended 5G IoT portable applications.

Inductive Reactance Isolated Dynamic Seawater Monopole Antenna of High Efficiency

Inductive Reactance Isolated Dynamic Seawater Monopole Antenna of High Efficiency

Dual-Band 2 × 1 Monopole Antenna Array and Its MIMO Configuration for WiMAX, Sub-6 GHz, and Sub-7 GHz Applications

This study introduces a cost-effective monopole antenna array and its MIMO configuration. The single element consists of a rectangular patch monopole featuring five circular slots at the center, accompanied by two thin slots at the top, offering a wide bandwidth (2–7.62 GHz) and a peak gain of 3.8 dBi. For gain improvement, a 2 × 1 antenna array is demonstrated. This antenna array exhibits dual-band behavior; spans from 2 to 3.71 GHz and from 5.9 to 7.54 GHz; covers the 2.5 GHz band (2.3–2.7 GHz), a significant portion of the n78 band (3.3–3.71 GHz), and the n96 band (5.925–7.125 GHz); and is assigned to WiMAX, sub-6 GHz, and sub-7 GHz applications, respectively. The antenna array achieves a peak gain of 6.47 dBi. Lastly, a two-element MIMO configuration derived from the 2 × 1 array is designed. Implementing a defected ground structure (DGS) on the ground plane plays a crucial role in enhancing the isolation from 7 dB to 20 dB. The presented MIMO antenna covers the desired frequency bands of 2.5 GHz, n78, and n96 with a peak gain of 7.5 dBi and high radiation efficiency (<99%), which qualifies it for WiMAX, sub-6 GHz, and sub-7 GHz applications.

Dual-Band Millimeter-Wave MIMO Antennas For 5G Wireless Implementation

For 5G wireless applications, this exploration proposes a dual-band 28/38 GHz 4-component MIMO array depending on duplex-mode planar monopole antennas. Four planar monopole antennas are part of the layout framework, situated at the districts of a Rogers RO4003 substrate measuring 20 by 20 mm2 and with a dielectric constant of 3.55. The form of the suggested placoid monopole antenna is crescent-shaped. We created a notch at the bottom and inscribed two rectangular holes on each side to get the required behaviour and execution. For enhancement of isolation, we also employed a limited ground plane. Antenna elements can achieve significant isolation (> − 23 dB) using spatial and scattering behaviour approaches. A illustration of the four-element MIMO array is created, manufactured, and measured to multifariousness the outline idea. The investigational outcomes demonstrate that the suggested antenna has strong isolation and high efficiency while covering the 27.25–29 GHz and 34.5–41 GHz bands. Additionally, studies are done on the channel capacity, realized gain, and radiation pattern. The obtained findings suggest that, for millimeter-wave 5G MIMO implementation, the proposed MIMO antenna might be an excellent application-oriented design.

Enhancing Diversity and Isolation Performance for a Four-Port Mimo Antenna in FR-1 5G Frequency Bands

The paper aims to improve the diversity parameters and isolation of a four-port Multiple-Input Multiple Output (MIMO) antenna configured as 4 × 1 for the 5G-NR FR-1 N78/77/48 band. The 4-port MIMO design entails the incorporation of dual sets of monopole antennas. Each pair of monopoles in this configuration arranges the second monopole to mirror the first one within its set. The MIMO antenna design incorporates Rogers RO3003 substrates with a ϵr of 3.2. The antenna size is compact, with dimensions of 34 × 129.5 × 1.6 mm3. The design of the four-port MIMO antenna introduced parasitic decoupling elements between the antennas, a defected ground structure (a T-shaped stub), and the incorporation of a grounding branch on the ground plane. These measures effectively mitigate the coupling between the antennas. The antenna functions within the frequency range of 2.25 GHz to 4.25 GHz, offering a bandwidth of 2 GHz with a peak gain of 4.0 dBi at 3.52 GHz. The diversity performance of the suggested MIMO antenna is evaluated using the parameters TARC, E.C.C., D.G., CCD/CCL, and M.E.G. The values obtained are as follows: starting from −15 dB, 0.0408, 9.989 dB, 0.08 bits/s/Hz, and 0.48 dB, respectively. According to both simulated and measured data, the MIM0 antenna system design presents good isolation capabilities, excellent diversity performance, and robust impedance matching. This can be a good option for FR-1 5G-NR N78/77/48 band communication.

Design of a Circularly Polarized Planar Monopole Antenna with a Simplified Radiator Structure for UWB Applications

The demand for wideband circularly polarized (CP) antennas in wireless communication applications has been increasing, given that it offers reliable signals with reduced interference. In particular, planar monopole antennas are a popular choice for use in CP applications due to their compact size and ease of integration. However, achieving CP characteristics often requires complex modifications, an increased antenna size, and design complexity. To address these challenges, this study proposes a simplified radiator structure modification for CP planar monopole antennas and validates the performance of the proposed antenna for ultra-wideband (UWB) applications by conducting both frequency-domain and time-domain analyses. The size of the proposed antenna is 34 mm × 41 mm × 1.6 mm, with FR-4 as the substrate. Both the -10 dB <i>S</i><sub>11</sub> bandwidth and 6 dB axial ratio axial ratio is 3.46–5.5 GHz, with the radiation patterns in the frequency range of interest being omni-directional. The proposed UWB CP antenna also yields decent antenna performance in time-domain analyses, such as the antenna fidelity factor and the system fidelity factor.

Design and Development of Conformal Body Centric Antenna for WBAN Application

In this paper, a conformal body centric antenna for wireless body area network (WBAN) applications is discussed. These designs are low-cost, low-profile circular and ring-shaped monopole antennas. Operational frequency of antenna is range from 2.5–10.6 GHz to meet the requirements of WBAN systems. The antenna is intended to be body- centric and conformal, which means for best performance, it is placed close to the body and conforms tothe shape of the human body. The radiation patterns are measured at 2.5 Ghz frequency. The substrate used for design is FR-4. The simulation results show that the proposed antenna has good impedance matching, a broad bandwidth of 122 MHz, and a gain of 4.8 db. The radiation pattern of the antenna is omnidirectional, which is desirable for wireless communication applications. Monopole antenna is designed and simulated using the Ansys EDT (HFSS) software. The monopole antennas are also fabricated in real time with proposed specifications. The proposed antenna can be used in various wireless communication systems such as WLAN, RFID, and Bluetooth, where low cost, compact size and critical design are considered.

Thermopneumatic Liquid Metal Radiofrequency Switch Actuated by Low‐Boiling‐Point Fluid

Existing radiofrequency (RF) switches used in reconfigurable antennas often encounter performance issues such as high insertion loss, low isolation, and nonlinear effects of the switch. To address these issues, this article presents a liquid metal RF switch that utilizes a heated low‐boiling‐point fluid (LBPF) to drive the movement of a eutectic gallium‐indium alloy (EGaIn) plunger to turn the switch on/off. The operating principle of the switch is to use the pressure difference generated by the liquid–vapor phase change of the LBPF to make the EGaIn plunger to contact with, or disconnect from the copper electrodes of the switch. The performances of the RF switches actuated by different LBPFs are respectively investigated, and the results show that all RF switches have millisecond response times, and the contact resistances are as low as 0.14 mΩ. In addition, good RF performances are achieved, with an insertion loss of less than 3 dB and isolation of more than 17 dB in the frequency band from 0 to 2 GHz, and no nonlinear effects. This study also validates the performance of the proposed switch for frequency reconfiguration of a folded monopole antenna.

A Compact Dual-polarized Probe-fed UWB Antenna System for Breast Cancer Detection Applications

This article proposes an electrically small, probe-fed Ultra-Wideband (UWB) monopole antenna on a slotted truncated ground plane for breast cancer detection. The physical footprint of the proposed antenna element is 33 mm × 35 mm × 0.5 mm. This element is designed on the low-cost FR4 Epoxy substrate with a thickness of 0.5 mm. The proposed antenna has an electrical size of 0.33λ × 0.35λ × 0.005λ at the lowest frequency of operation; the radiator offers an impedance bandwidth of 8.34 GHz, which implies a fractional bandwidth of 115.5%. A compact dual-polarized antenna topology with two orthogonally placed probe-fed monopole antennas is proposed to achieve polarization diversity. The impedance characteristics of the individual radiating elements are maintained in spite of the electrical proximity of the radiators. The numerically computed and experimentally measured results of dual-polarized electrically small UWB antenna agree quite well. The proposed dual-polarized antenna topology is investigated for its utility in breast cancer detection in simulation.

Mechanical Robustness Enhanced Flexible Antennas Using Ti3C2 MXene and Nanocellulose Composites for Noninvasive Glucose Sensing.

Electromagnetic sensors with flexible antennas as sensing elements have attracted increasing attention in noninvasive continuous glucose monitoring for diabetic patients. The significant radiation performance loss of flexible antennas during mechanical deformation impairs the reliability of glucose monitoring. Here, we present flexible ultrawideband monopole antennas composed of Ti3C2 MXene and cellulose nanofibril (CNF) composite films for continuous glucose monitoring. The flexible MXene/CNF antenna with 20% CNF content can obtain a gain of up to 3.33 dBi and a radiation efficiency of up to 65.40% at a frequency range from 2.3 to 6.0 GHz. Compared with the pure MXene antenna, this antenna offers a comparable radiation performance and a lower performance loss in mechanical bending deformation. Moreover, the MXene/CNF antenna shows a stable response to fetal bovine serum/glucose, with a correlation of >0.9 at the reference glucose levels, and responds sensitively to the variations in blood glucose levels during human trials. The proposed strategy enhancing the mechanical robustness of MXene-based flexible antennas makes metallic two-dimensional nanomaterials more promising in wearable electromagnetic sensors.