Stable Omnidirectional Radiation Pattern Research Articles

Development and investigation of a compact band-notched MIMO antenna attaining wideband isolation for UWB applications

The sequential layout of a portable ultra-wideband (UWB) monopole antenna, transforming into a compact band-notch (3.15–4.3 GHz rejecting the Wi-Max and the C-Band) multiple-input multiple-output (MIMO) antenna is described in this paper. The diversity layout is designed within a compact size of 39 (l) × 18 (W) mm2. Due to the opposite orientation of the two radiators in the diversity configuration and the use of a rectangular parasitic strip near the feed lines, high and wideband isolation (of >20 dB) is attained over the entire UWB spectrum. The proposed layout depicts a stable omnidirectional radiation pattern and a maximal gain of 1.82 dB. The envelope correlation coefficient (ECC) is found to be below 0.18 for the entire UWB spectrum. Empirical verifications in terms of vital diversity parameters and analogy with competing layouts strengthen the candidature of the intended MIMO layout for UWB wireless portable applications.

Broadband Dual-Polarized Cup Dielectric Resonator Antenna With Stable Omnidirectional Radiation Patterns

Broadband Dual-Polarized Cup Dielectric Resonator Antenna With Stable Omnidirectional Radiation Patterns

UN AMPLIO ESPECTRO DE SUSTRATO HEXAGONAL DE OCTAVO MODO PARA APLICACIONES EN BANDA C, S, X

The following article explains how to make a basic ultra-wide bandwidth (UBW) wearable fractal antenna. The antenna is printed on denim fabric with a dielectric constant of 1.7 and a loss tangent of 0.02. The suggested antenna is 45 x 44.92 x 0.5 mm3. The antenna is fed by an inserted microstrip line with a decreased ground structure. It operates at ultrawide band frequencies of 4.36 GHz to 11.12 GHz. The antenna offers an omnidirectional radiation pattern with a gain of more than 2.4 dBi across the entire working band... It achieves a bandwidth of 6767 MHz. The proposed antenna possesses key characteristics such as a simple structure, ease of fabrication, stable omnidirectional radiation pattern, reasonable gain, and directivity, which make it suitable for applications in the C, S, and X bands. Keywords: Textile antenna, UWB, denim fabric, flexible antenna, denim substrate

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 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.

Design of compact slot antenna and octagonal blended shape antenna

ABSTRACT In this paper, two new compact halved-size single and UWB antennas are proposed for WiFi and UWB applications. The single-band compact halved size slot antenna is proposed for WiFi applications at 2.4 GHz. The resonant frequency of the conventional slot antenna can be reduced by cutting the antenna into two halves and without using any lumped elements inside the slot. Moreover, the impedance and radiation characteristics of the proposed halved-size antenna are suitable for WiFi applications at 2.4 GHz. The proposed WiFi antenna has a miniaturised size of 25 × 16.5 × 0.813 mm3. Then, an octagonal blended-shape antenna (OBSA) for UWB applications is proposed. The UWB band from 3.1 GHz to 10.6 GHz is encompassed by the halved-size OBSA using the same cutting concept. Furthermore, a grounded L-stub is added on the top side to improve the reflection coefficients. The proposed OBSA has a compact size of 28 × 13 × 0.813 mm3 with stable omnidirectional radiation patterns. Simulation and measured results are in good agreement.

Notice of Violation: A 3D Printed Multi-Mode Conical Dielectric Resonant Antenna With Stable Omnidirectional Radiation Patterns for 5G Vehicle Picocell Applications

Notice of Violation <br><br>“A 3D Printed Multi-Mode Conical Dielectric Resonant Antenna With Stable Omnidirectional Radiation Patterns for 5G Vehicle Picocell Applications” <br>by Xuyi Zhu, Bing Zhang, Zhijiao Chen, Yanping Zhou, Kama Huang, Tiancang Zhang, Juan Yang, and Xiao An <br>published in the IEEE Transactions on Vehicular Technology, Digital Object Identifier: 10.1109/TVT.2022.3196909. <br><br>The authors of this paper violated the IEEE’s Publication Principles. An author name was included in the Early Access version of this paper who did not contribute to the work and was added without their consent. The non-contributing author’s name has been removed <br><br> <br/> A multi-mode 3D-printed conical dielectric resonant antenna (DRA) with a stable omnidirectional pattern is proposed. It covers the band of 1.75-3.64 GHz and 4.96-6.01 GHz. Multiple modes in the conical DRA are effectively excited which are the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01δ</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03δ</sub> modes intrinsic to the dielectric resonator (DR). The combination of probe and sleeve is used to feed the DR to excite additional modes such as the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> modes and the sleeve mode respectively to further extend the bandwidth of the antenna. The sleeve also helps to tune the current distribution of the probe's high-order modes when the DRA is mounted on a finite-size ground plane. The profile of the conical DRA is properly designed to overcome the tilt of the radiation pattern by the ground plane, by which stable omnidirectional radiation patterns are achieved across the whole operating frequency band. The characteristic mode theory and an eigenmode solver are used to verify the numerical analysis. The 3D printing technology is used to fabricate the DRA. Powered LEDs are placed inside the 3D printed DRA to enable its lighting function. The proposed antenna can be fixed on the vehicle's roof for vehicle-to-everything (V2X) communication. It has satisfactory electromagnetic compatibility (EMC) with other vehicle-mounted electronic devices. It is a good candidate for 5G vehicle picocell applications.

A Four Element Stringray-Shaped MIMO Antenna System for UWB Applications.

This paper presents a CoPlanar-Waveguide (CPW)-fed stingray-shaped Ultra-WideBand (UWB) Multiple-Input-Multiple-Output (MIMO) antenna system designed for microwave imaging applications. Featuring a diagonal square with four inner lines and a vertical line at the center from toe to tip with a CPW feed line, the unit antenna element looks like a stingray fish skeleton and is, therefore, named as a stingray-shaped antenna. It offers a bandwidth spanning from 3.8 to 12.7 GHz. Fabricated on a 31mil RO5880 RF teflon substrate with a relative permittivity of 2.2, the proposed antenna has dimensions of 26 × 29 × 0.787 mm3. The maximum realized gain achieved is 3.5 dBi with stable omnidirectional radiation patterns. The antenna element is used in a four-antenna MIMO configuration with an isolation-improving structure at the center. The MIMO system has dimensions of 58 × 58 × 0.787 mm3 with a maximum realized gain of 5.3 dBi. The antenna's performance in terms of MIMO parameters like Envelope Correlation Coefficient (ECC) and Diversity Gain (DG) is within satisfactory limits for medical imaging applications. Time domain analysis also yields positive results, allowing its integration into a breast phantom tumor detection simulation. The simulation and measurement results demonstrate excellent agreement, making this antenna a promising candidate for microwave imaging and biomedical applications.

Microstrip dual band hybrid directional resonator antenna with volume reduction

This paper presents a novel design of a single-layer, horizontally polarized, dual-band, omni- and multi-directional hybrid dielectric resonator antenna (DRA) feeding through a 50 Ω coaxial connector. The proposed antenna consists of an FR4 substrate, a regular ground plane and a cross-shaped patch. The connector is placed at the middle point of the square ground plane. Above the microstrip patch, four similar solid dielectric resonator elements are placed diagonally. These DRA structures generate the TE111, hybrid HEM22δ modes and put up an ideal magnetic dipole and an electric quadrupole far-field radiation pattern. To verify the idea, an optimized antenna model is fabricated and tested. A reasonable agreement between the measured and simulated results is obtained. The measured impedance bandwidths of the TE111 and HEM22δ modes are 4.26 % (2.9–3.2 GHz) and 4.34 % (4.4–4.6 GHz), respectively. The proposed antenna has a stable omnidirectional radiation pattern at the first resonance frequency and a directional radiation pattern at the second resonance frequency and provides volume reduction.

Low cross polarized leaf shaped broadband antenna with metasurface as superstrate for sub 6 GHz 5 G Applications

This article presents the design, circuit model analysis, and realization of a metasurface-based novel leaf-shaped antenna for sub 6 GHz 5 G NR frequency bands like n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), n79 (4.4–5 GHz), and n90 (2.4–2.6 GHz) applications. Primarily, a leaf-shaped microstrip planar antenna is designed and provides a broad impedance bandwidth of 77.43% (2.2–4.98 GHz), a peak gain of 4.51 dBi, and a high radiation efficiency of 94.16%. The planar antenna is integrated with a 5 × 3 elements periodic metasurface (MS) array to enhance radiation performance. Both the radiating leaf planar and the MS layer have been designed on a low-cost FR4 epoxy substrate, and equivalent circuit models have been developed for both successively to validate the EM simulated results. The overall dimensions of the planar antenna with MS layer are 0.45 λ0 × 0.27 λ0 × 0.108 λ0, (λ0 corresponds to lowest resonant frequency f=2.7 GHz). The tested antenna with MS superstrate covers a broad range of operating frequencies from 2.29 to 4.78 GHz (2.49 GHz) with a − 10 dB impedance fractional bandwidth of 70.43% and has an excellent reflection coefficient of more than − 35 dB for the entire operating band. The experimental peak gain and higher radiation efficiency are 8.76 dBi and 96.6%, respectively. Moreover, all these parameters are extremely high in single-layer planar antennas, including the stable omnidirectional radiation pattern with very low cross-polarization of − 53.34 dB.

Fractal Sectoral Monopole Antenna for UWB Band Applications

This paper proposes a fractal monopole antenna based on a sectoral-shaped patch. To improve thegain of the proposed antenna over a larger bandwidth, the matching was enhanced by attaching two rectangular stubs to the feeding line. The antenna, which is built on an FR4 epoxy substrate with εr =4.3 and a loss tangent of 0.018 has a compact size of 28 mm×31 mm×1.6 mm. The antenna covers the UWB range and extends to about the 22 GHz frequency, as well as offers omnidirectional radiation patterns. The optimized configuration was fabricated and tested. The impedance bandwidth of the proposed antenna is about 155% with a reflection coefficient better than −10 dB and has a maximum gain of nearly 4 dBi with a relatively stable omnidirectional radiation pattern.

Inverted Sierpinski Carpet fractal‐inspired dielectric resonator antenna for wideband applications

AbstractThis communication explains a novel approach for attaining wideband inverted Sierpinski Carpet fractal geometry with a rectangular shape dielectric resonator antenna (DRA). Dielectric Resonators (DRs) have advantages, like, high gain, efficiency, wide bandwidth, low conduction loss, and minimum surface waves. Rectangular shape DR (εrdr = 9.8, 14 × 12 × 8 mm3) made from alumina (Al2O3) is mounted on top of a primary square patch. Inverted Sierpinski fractal geometry provides the benefit to decrease the volume to the surface area without removing elements from the patch. The proposed fractal DRA is printed on an FR4 substrate (εr = 4.4), fed with a 50‐Ω microstrip feed line, and has a compact size of 38 × 38 × 9 mm3. At the backside of the antenna, an extended stub from the partial ground plane enhances impedance matching from 4 to 5 GHz. The prototype of the proposed DRA is fabricated and measured. The antenna functions with an impedance bandwidth of 98.84% for S11 &lt; − 10 dB, covering 3.5–10.34 GHz of the ultrawideband range. The proposed DRA offers a stable omnidirectional radiation pattern, maximum measured gain of 7.01 dBi, and has an average efficiency above 97% over the region of operation. These features make the proposed DRA applicable for cellular communication repeaters, local area networks, and vehicular communication applications.

Compact Slit-Loaded ACS-Fed Monopole Antenna for Bluetooth and UWB Systems With WLAN Band-Stop Capability

A compact asymmetric coplanar strip (ACS)-fed monopole antenna is presented, which operates within the Bluetooth and UWB frequency bands with the capability to simultaneously reject the lower WLAN interfering band. The antenna consists of an inverted right triangle patch monopole loaded by open-ended L-shaped slits not only to produce the additional 2.4 GHz passband to the UWB design but also to achieve stopband characteristics around 5.2 GHz. The conceptual equivalent circuit model as well as characteristic mode analyses are carried out in the design evolution process. The proposed antenna has an overall size of only 20 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times10$ </tex-math></inline-formula> mm, having the smallest area among the so far developed designs, which can be easily integrated within any wireless gadgets. A prototype is fabricated and measured to validate the design, demonstrating the predicted behavior fairly achieved by full-wave analysis. The antenna −10 dB operating bandwidth ranges from 2.38 to 2.42 GHz and from 3.35 to 11 GHz while rejecting from 4.69 to 5.2 GHz. Unlike the unwanted stopband, where the radiation characteristics are adequately deteriorated, the proposed antenna fairly provides stable omni-directional radiation patterns in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${H}$ </tex-math></inline-formula> -plane, and has an average efficiency (gain) of 87.3% (2.6 dBi) in the desired passband. As far as the antenna transient behavior is concerned, an adequate measured (simulated) system fidelity factor of 0.7 (0.68) is achieved for the transmission of impulse-type UWB signals in the face-to-face configuration.

The Small UWB Monopole Antenna with Stable Omnidirectional Radiation Pattern

Ultra Wideband (UWB) technology is an unmodulated wireless digital communication system that uses an extremely short duration pulse to transmit information bit. Because of this pulse, the UWB system needs a very wide bandwidth. Federal Communication Commission (FCC) has regulated the 3.1 – 10.6 GHz frequency spectrum for UWB. Since FCC released this frequency, many research in telecommunication have been done on UWB systems. One of them is a development of an Antenna that is suitable for UWB devices. UWB antenna characteristics require FCC band, omnidirectional radiation pattern, and compact size. In order to meet these needs, an antenna with a simple structure in the form of a monopole patch antenna with a similar patch size and ground width has been designed. The antenna is built on an FR4 – epoxy substrate material, with 4.4 dielectric constant and 1.6 mm thickness. The antenna feeding structure consists of two 100 Ω and 50 Ω lines with a wideband impedance matching scheme using tapered side and tapered transformers. The antenna design and optimization processes are conducted using electromagnetic simulation software, and measurements are carried out in an anechoic chamber. Simulation and measurement results show good agreement, and the antenna can work at frequencies 3.5 - 11.3 GHz with a gain of 1.5 – 3.25 dBi and stable omnidirectional radiation patterns. The antenna has dimensions of 27 × 8 × 1.6 mm, which are smaller than the antenna reported in the last research and suitable to be applied on various UWB devices.

Design of miniaturized tri‐band antenna based on differential evolution algorithm

AbstractA novel highly miniaturized triple band structure based on Z‐slots‐shaped antenna is presented in this letter, with only 0.0015 footprint, where is the free space wavelength at 1.3 GHz. The proposed design can generates three resonant frequency bands (1.3–1.62 GHz), (2.22–2.59 GHz), and (3.24–3.65 GHz) with −10 dB reflection coefficient, a triple band function is achieved by etching tow connected Z‐shaped‐slots in the radiating element and the differential evolution algorithm is then used to control the currents path, the prototype of the proposed antenna is printed on a single substrate layer and fed via coplanar waveguide CPW technology. The measured and simulated results are in good agreement, and validate the design principle, the results show that the antenna has a compact size (19.5 × 17.6 mm2), aside from its planar design, simple manufacturing, and low cost to fabricate, this antenna exhibits stable omnidirectional radiation patterns in E plane as well as bidirectional radiation patterns in H plane, making it an ideal device for multiband applications.

Monopole Antenna with Enhanced Bandwidth and Stable Radiation Patterns Using Metasurface and Cross-Ground Structure.

In this paper, a printed monopole antenna with stable omnidirectional radiation patterns is presented for applications in ocean buoy and the marine Internet of Things (IoT). The antenna is composed of a rectangular patch, a cross-ground structure, and two frequency-selective surface (FSS) unit cells. The cross-ground structure is incorporated into the antenna design to maintain consistent monopole-like radiation patterns over the antenna's operating band, and the FSS unit cells are placed at the backside of the antenna to improve the antenna gain aiming at the L-band. In addition, the FSS unit cells exhibit resonance characteristics that, when incorporated with the cross-ground structure, result in a broader impedance bandwidth compared to the conventional monopole antenna. To validate the structure, a prototype is fabricated and measured. Good agreement between the simulated and measured results show that the proposed antenna exhibits an impedance bandwidth of 83.2% from 1.65 to 4 GHz, compared to the conventional printed monopole antenna. The proposed antenna realizes a peak gain of 4.57 dBi and a total efficiency of 97% at 1.8 GHz.

A new design of a printed reconfigurable coplanar multiband antenna

The demand for multi-functional components has increased enormously in recent years. Advances in integrated technology have enabled researchers to adapt diverse applications operating at different frequencies in a single wireless device. A compact broadband coplanar waveguide (CPW)-fed square aperture monopole antenna with inverted-L grounded strips is first described. The proposed antenna has a small size of 60×60×0.74 mm3 and has excellent performances which include a good input impedance matching with a much wider operating bandwidth, an excitation of the circular polarization at 2.45 GHz, and a stable omnidirectional radiation pattern. Then, a multiband reconfigurable antenna design is developed from this structure. The frequency reconfigurable approach is obtained using a varactor diode. In this work, it is observed that frequency diversity can be obtained by varying the value of the capacity by leaving the dimensions antenna unchanged. The results are given using CST microwave studio and show good performances in terms of return loss, bandwidth, gain and radiation pattern and demonstrate that the proposed antenna offers a reconfigurable solution for multi-standard wireless communication applications.

Efficiency Enhanced Seven-Band Omnidirectional Rectenna for RF Energy Harvesting

In this article, a seven-band omnidirectional rectenna is proposed for the first time to harvest RF energy. The designed rectenna operates in the following practical and up-to-date frequency bands: GSM1800 (1.8 GHz), LTE (2.1 GHz), WLAN/Wi-Fi (2.4 and 5.8 GHz), and 5G bands (2.6, 3.5, and 4.9 GHz). To obtain the multiband rectenna, a novel seven-band rectifier is introduced and composed of three optimized single shunt diode rectifiers in parallel. Overall RF-to- dc conversion efficiencies as high as 44.4% @ 1.84 GHz, 43.9% @ 2.04 GHz, 45.4% @ 2.36 GHz, 43.4% @ 2.54 GHz, 36.1% @ 3.3 GHz, 32.4% @ 4.76 GHz, and 28.3% @ 5.8 GHz are achieved at an input power level of −10 dBm. Moreover, a broadband omnidirectional monopole antenna is further codesigned with elaborate impedance matching to the rectifier. The antenna can harvest RF energy in the bandwidth of 1.67–5.92 GHz ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}_{\mathbf {11}}$ </tex-math></inline-formula> no more than −10 dB) with stable omnidirectional radiation patterns. By integrating the rectifier and the monopole antenna in a low profile, a prototype of the rectenna was manufactured and tested. The experimental results demonstrate that the proposed rectenna has competitive performance in terms of RF-to- dc conversion efficiency and band coverage, indicating enormous potential for numerous battery-free or low-power-needed applications in the real world.

Dual-band omnidirectional coupled-fed monopolar filtering antenna

A dual-band omnidirectional coupled-fed monopolar filtering antenna is designed in this paper. The proposed filtering antenna consists of three stacked circular substrates. A via-loaded annular ring and an annular ring are fabricated on the top of bottom and middle substrates respectively. Four adjustable resonant modes are introduced by this way, which are combined in pairs to generate two independently controllable operating bands. Meanwhile, each resonant mode can produce corresponding omnidirectional radiation, making the proposed filtering antenna have omnidirectional radiation function. There are four adjustable radiation nulls (RNs) located at the both sides of two passbands realized by the coupled-fed via-loaded annular ring and the circular patch printed on the uppermost substrate. Hence, high skirt selectivity can be obtained. The proposed dual-band filtering antenna is simulated, fabricated and measured. The simulation and measurement are in excellent agreements. It is proved that the proposed filtering antenna realizes a stable omnidirectional radiation pattern in the azimuth plane with the cross-polarization level of lower than 20 dB. Additionally, the measured results display that the 10-dB impedance bandwidths are 6.3 % (2.47–2.63 GHz) and 6 % (5.38–5.71 GHz), respectively. The maximum realized gains are 2.6 and 5.2 dBi for two working bands with the out-of-band suppression of more than 15 dB.

A band-notched filtering omnidirectional dielectric resonator antenna with metal patches

In this paper, a laminated planar feed structure has been proposed to excite the omnidirectional radiation modes of a dielectric resonator (DR): TM01δ, TM011+δ and TM012+δ. The resonant frequencies of the three modes are 2.44, 2.78 and 3.10 GHz respectively. By combining three resonant frequencies, the proposed band-notched dielectric resonator antenna (DRA) achieves a wide impedance bandwidth and stable omnidirectional radiation pattern in the whole passband. The simulated passbands of the proposed band-notched DRA are 2.23–2.56 GHz and 2.71–3.17 GHz. The laminated planar feed structure also can produce an adjustable radiation null (RN) at the upper edge of the passband, improving the skirt selectivity. To suppress in-band interference, four metal patches have been plated on the side walls of the DR and another adjustable RN (notched frequency) is generated within the passband. By changing the size of the metal patch, the notched band can be adjusted. In a word, the proposed DRA has numerous advantages such as wideband, stable omnidirectional radiation, filtering and band-notched functions. A prototype has been fabricated and measured for demonstration, and the measured results are coincided with the simulated ones.