Monopole-like Radiation Pattern Research Articles

광대역 특성을 갖는 3층형 소형 모노콘 안테나

In this study, an electrically small 3-stage monocone antenna with wideband characteristics is proposed. The proposed antenna consists of a 3-stage monocone radiator, a circular disk located above the radiator, shorting pins connecting the circular disk and the ground plane, and parasitic structures. The impedance matching characteristics in the high-frequency band are improved by dividing the monocone radiator into three stages. The insertion of a slot in the circular disk improves the mid-frequency band performance. The low-frequency band is expanded by using shorting pins. In addition, by attaching parasitic structures to the ground plane, the impedance-matching characteristics in the mid-frequency band are further improved. The proposed antenna has a −10 dB impedance bandwidth ranging from 0.98 to 11.1 GHz and a monopole-like radiation pattern.

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 conical-beam dual-band double aperture-coupled stacked elliptical patch antenna design for 5G

This study investigates a dual-band, aperture coupled and stacked elliptical patch antenna with conical radiation. To obtain such characteristics, the TM21 mode of the radiating elliptical patches is excited by utilizing two special apertures and shorting planes. The proposed antenna operates both at 2.45 GHz and 3.5 GHz. The design aims to be used indoor applications of 5G operating in both free and planned 5G bands, respectively. Therefore, the low-profile antenna element that has a monopole-like radiation pattern is a good candidate for two-dimensional arraying. The design steps and the evolution of the proposed antenna are presented in detail. The simulation and experimental results reveal many similarities regarding the scattering parameters, radiation patterns, and gain. The scattering parameter, S11 is less than -10 dB in both operating bands. Novelties of the proposed study are the configuration and choice of the apertures as well as stacking structure and miniaturization techniques in elliptical patches.

A compact double-inverted Ω-shaped dual-band patch antenna for WLAN/WiMAX applications

Abstract In this study, a new compact dual-band antenna with overall size of 11 × 14.46 × 1.6 mm3 has been designed, fabricated and tested. The proposed antenna consists of two inverted Ω-shaped strips loaded with two different comb structures. The fist comb of six elements connected to the first Ω-shaped radiating branch is used to decrease the second band lower cut-off frequency and cover the intended WLAN and WiMAX applications. In order to cover the 2.45 GHz WLAN band and further reduce the antenna dimensions, a second comb structure of 14 elements is attached to the upper radiating branch. The fabricated antenna covers the frequency bands from 2.42 to 2.6 GHz and from 4.25 to 6.77 GHz with a reflection coefficient of |S 11| ≤ −10 dB. The antenna shows an omnidirectional radiation pattern in the H-plane and a monopole-like radiation pattern in the E-plane. The measured results agree well with the simulated ones which indicate that the proposed antenna is suitable to be used in the WLAN/WiMAX applications.

A low‐profile dual‐mode antenna for unmanned aerial vehicles applications

A low-profile dual-mode antenna is proposed in this paper. The antenna is composed of a semi-rectangular-annular (SRA) coaxial line with sleeve loading structures vertically mounted on the ground plane. The proposed antenna has two radiation modes, mode 1 of the vertically polarised (VP) radiation characteristics at 500 MHz and mode 2 of the horizontally polarised (HP) radiation characteristics at 588 MHz. The two vertical components of the SRA coaxial line contribute to the VP radiation, which is achieved with the in-phase electric currents on the two vertical components by adjusting the length of the in-body inductive loading structures. The horizontal component of the SRA coaxial line is mainly contributed to HP radiation when the electric currents on two vertical components are reversed. And the antenna is well matched with the additional impedance matching network, which consists of two inductors and a capacitor. The height of the fabricated prototype is only 25.9 mm (about 0.04λ) at 500 MHz. The fabricated prototype possesses monopole-like radiation pattern at 500 MHz and loop-antenna-like radiation pattern at 588 MHz. The measured maximum gain of the proposed antenna at 500 MHz is −6.8 dBi, and the measured maximum gain of the proposed antenna at 588 MHz is 2.5 dBi. The antenna is suitable for unmanned aerial vehicles communication systems due to its advantages of low-profile and dual-mode radiation.

원통형 구조물이 결합된 광대역 소형 모노콘 안테나

In this paper, an electrically small wideband monocone antenna with cylindrical structures is proposed. The proposed antenna consists of a monocone radiator with cylindrical and sub-cylindrical structures, a circular disk, and shorting pins connecting the circular disk and the ground plane. By attaching the shorting pins from the circular disk to the ground plane, the low-frequency band is expanded, and by attaching cylindrical and sub-cylindrical structures to the monocone radiator, the impedance matching characteristics in the middle-and high-frequency bands are improved. The proposed antenna was manufactured using a 3D printer to reduce the weight, and the surface of the antenna was coated by spraying the conductive point. The proposed antenna had a −10 dB impedance bandwidth ranging from 0.52 GHz to 2.22 GHz and a monopole-like radiation pattern.

A Low-Profile Dual-Band Coaperture Monopolar Antenna Based on Cross-Layer Folded Structure

A dual-band coaperture monopolar antenna with a very low profile is investigated in this communication. A novel cross-layer folded structure is proposed to construct a single-band monopolar antenna in the lower band. It can provide enough space for another higher band section to be integrated together without extra profile. Meanwhile, by adding a high-frequency radiation element to the reserved space, a dual-band coaperture antenna with independent frequency control is obtained. Moreover, by exciting 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">02</sub> modes in both bands, the proposed antenna can achieve a relatively large impedance bandwidth of 10.9% in the lower band and 14.6% in the upper band with a thickness of 3.14 mm. Stable monopole-like radiation patterns are achieved within the two bands and the gains in the lower and upper bands are 5.2–5.8 and 3.7–5 dBi, respectively. Compared with other works, the proposed antenna features its low-profile and independent band performance.

Low-Profile Wideband Omnidirectional Antenna for 4G/5G Indoor Base Station Application Based on Multiple Resonances

A novel low-profile antenna with monopole-like radiation characteristics is proposed for 4G/5G indoor micro ceiling base station applications. The proposed antenna consists of a top loading disk, two polygonal copper sheets, which are orthogonally intersected, and a circular printed circuit board (PCB), which serves as the ground. A prototype is fabricated and measured. The proposed antenna has a very low profile of 0.057λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> is the free-space wavelength at the lowest frequency of the operating band. A fractional bandwidth of 85.3% ranging from 1.6 to 3.98 GHz with |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | <; -10 dB is achieved, which covers the 4G LTE band and 5G N78 band. The proposed antenna demonstrates consistent monopole-like radiation pattern in the whole working band, which is very suitable and well designed for indoor ceiling base station applications.

A Conformal Ultrawideband Antenna With Monopole-Like Radiation Patterns

A simple conformal ultrawideband (UWB) antenna with monopole-like radiation patterns is proposed in this communication. To achieve the wide bandwidth, two rings are arranged concentrically around the main annular-ring circular patch antenna, in which two rectangular slots are added. The antenna has monopole-like radiation patterns generated by combining four propagation modes of TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> , TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> , TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> , and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">04</sub> throughout the operating bands. To enhance the flexibility and robustness, the proposed antenna is fabricated using conductive fabric embedded into polydimethylsiloxane (PDMS) polymer. To our knowledge, this is the first flexible UWB antenna with monopole-like radiation patterns reported in the open literature. The measured results show that the antenna achieves a 10 dB return loss bandwidth from 2.85 to 8.6 GHz. Monopole-like radiation patterns are maintained throughout the frequency band, agreeing well with simulated results. This has been validated through the measured mean realized gain (MRG) pattern from 2.85 to 8.6 GHz. The fabricated antenna was bent and tested at various curvatures to verify its conformability. To evaluate suitability for UWB communications, the system-fidelity factors of the antenna are investigated using full-wave analysis in CST Microwave Studio, in both flat and bent conditions, validating its potential for UWB pulse transmission.

Electrically Small Platform-Based Antennas for an Unmanned Ground Vehicle

We present a design strategy for platform-based antennas operating on electrically small platforms such as unmanned ground vehicles (UGVs). Specifically, we report the design of a platform-based antenna operating at the lower end of the very-high-frequency (VHF) band for a small UGV with physical dimensions of 99 cm × 67 cm × 39 cm. The antenna is mounted on the bottom of the platform resulting in an extremely low-profile design and generating vertically polarized, monopole-like radiation patterns. Using characteristic-mode theory (CMT), performance metrics of the antenna including its maximum potential bandwidth and radiation patterns are investigated. The performance of the antenna when operating in a realistic operational environment is analyzed using full-wave electromagnetic simulations. A full-scale prototype of the antenna mounted on the bottom of the vehicle was fabricated and experimentally characterized. Finally, the design of this low-profile antenna is extended to a two-element antenna array mounted on the same platform and a prototype of this two-element array was fabricated. Basic experiments were conducted to study impedance matching and mutual coupling effects in this electrically small antenna array. The performance of this array as part of a two-element direction-finding system was investigated through computer simulations.

A Triband Patch Antenna with Monopole-like and Patch-like Radiation Patterns for Multifunctional Wireless Systems

A triband patch antenna with monopole-like and patch-like radiation patterns for multifunctional wireless systems is proposed. The antenna consists of a single square radiation patch with an annular slot, a ground plane, and a top-loaded metal sheet. The top-loaded metal sheet is shorted to the ground plane for producing a zeroth-order resonant (ZOR) mode, which has an omnidirectional radiation pattern at the lowest operation band, and its performance is robust to the location of the probe feed. With the annular slot and the off-center probe feed, a dual-resonant TM01 mode is excited, yielding unidirectional radiation patterns for the two upper operation bands. The ZOR and the dual-resonant TM01 modes can be independently controlled, and a triband antenna prototype with a square patch of 24 mm is fabricated and tested. The first bandwidth is 2.5–2.7 GHz with omnidirectional radiation pattern, the second and the third bandwidths with unidirectional radiation are 3.3–3.9 GHz and 4.8–6.1 GHz, and the realized gains over the three bands are about 2.6, 6.5, and 7.5 dBi, respectively.

Dual‐band and dual‐polarised circular patch textile antenna for on‐/off‐body WBAN applications

A dual-band dual-polarised antenna for on-/off-body wireless body area network (WBAN) applications is presented, operating at Industrial, Scientific, and Medical bands of 2.45 GHz with circular polarisation and 5.8 GHz with vertical polarisation. The TM11 mode is used for the off-body mode in the first band because of its broadside radiation pattern, meanwhile, the TM02 mode is chosen for on-body mode due to its monopole-like radiation pattern in the second band. Composed of a circular patch with eight slots, the structure of the proposed antenna is simple, and it is fabricated with textile material. The performance of the antenna is investigated in free space and on the body. Then, the performance influenced by the bending of the antenna is discussed with a different bending radius. The specific absorption rate distribution is simulated on body tissue. And the maximum value at both bands is below the IEEE C95.3 standard of 1.6 W/kg. The acquired performance demonstrates that the proposed antenna can be applied to the applications of WBAN.

Three Wideband Monopolar Patch Antennas in a Y-Shape Structure for 5G Multi-Input–Multi-Output Access Points

Three wideband monopolar patch antennas (MPAs) integrated into a Y-shape structure for multi-input–multi-output (MIMO) operation in 3300–4200 MHz for fifth-generation (5G) access points are presented in this letter. Each MPA has an antenna height of 10 mm (about 0.11 λ at 3300 MHz) and a top-patch length of 22 mm (about 0.24 λ at 3300 MHz). Each MPA is capacitively excited through a feed strip at its corresponding top-patch center and is short circuited to the ground plane through two shorting strips. One shorting strip is at the top patch's open end and the other one is at the center of the Y-shape structure, which is the central shorting strip shared by all three MPAs. The three compactly integrated MPAs generate three decoupled waves with monopolelike radiation patterns. Good antenna performance of the three MPAs is also obtained.

A Wide Dual-Band Metamaterial-Loaded Antenna for Wireless Applications

A compact, wide dual-band antenna designed to resonate at 2.25 GHz and 5.4 GHz is proposed in this paper. The proposed antenna is a monopole rectangular patch designed to operate at 5 GHz. This basic structure is modified by introducing a metamaterial-based interdigital capacitor reactive loading that exhibits dual-band characteristics at 2.25 GHz and 5.4 GHz. A bandwidth greater than 1.4 GHz at the two resonant frequencies is obtained. The compact size of the proposed antenna is 0.0989λ&lt;sub&gt;0&lt;/sub&gt; × 0.0498λ&lt;sub&gt;0&lt;/sub&gt;, where λ&lt;sub&gt;0&lt;/sub&gt; is calculated at the first resonance. The antenna is etched on a FR4 substrate with dielectric constant &lt;i&gt;ɛ&lt;/i&gt;&lt;sub&gt;&lt;i&gt;r&lt;/i&gt;&lt;/sub&gt; = 4.4 and thickness of 1.6 mm. The simulated results exhibit considerable gain and wide impedance bandwidth at the resonant frequencies. Monopole-like radiation patterns are obtained at both the operating frequencies. The designed antenna can be applied in wireless local area networks and Wi-MAX wireless communications.

Probe Feed Multi-Element Multi-Segment Triangular Dielectric Resonator Antenna with RCS Analysis

The aim of the paper is to propose a design and analysis of multi-element multi-segment triangular dielectric resonator antenna (MEMS TDRA) with Radar Cross-Section (RCS). The proposed antenna has been excited through coaxial probe feed. The coaxial probe feed excites TM[Formula: see text] dominant mode fields within the TDR elements. A general guideline for wide bandwidth and high gain has been prepared for designing of MEMS TDRA. The model of the proposed MEMS TDRA has been studied through simulation (Ansoft HFSS software) and fabricated for measurement. The simulated antenna performance has good agreement with the measured one. The proposed MEMS TDRA performance has been compared with some similar type of previously published structure and found wider bandwidth and higher gain. The proposed MEMS TDRA provides monopole-like radiation pattern with nearly 39% bandwidth ([Formula: see text] dB). The average gain of 6.0 dBi has been found over the entire bandwidth. The RCS analysis has been performed for monostatic and bistatic modes at different frequencies and angles. The proposed antenna is appropriate for WLAN and WiMAX applications.

Dual-band slot microstrip patch antennas with dual-radiation modes for wireless communication

AbstractIn this paper, a novel compact dual-band microstrip patch antenna with dual-radiation modes is investigated. The proposed antenna consists of a rectangular ground plane, a U-shaped feed probe, and an H-shaped slot radiating patch. By adjusting the size of these structures, a dual-band antenna can be obtained. In the low-frequency band, the antenna can radiate one radiation beam with high gain. In the high-frequency band, the antenna can achieve monopole-like radiation pattern. Therefore, an antenna prototype is fabricated and measured for validation. Good agreement between the simulated and measured results is observed in this paper. The antenna's operating frequency ranges are 3.6–3.85 GHz in the low-frequency band and 5.1–6.1 GHz in the high-frequency band with the reflection coefficient less than −10 dB. At 3.7 GHz, the antenna radiate one beam with 8.8 dBi realized gain. At 5.5 GHz, it exhibits dual-radiation beams directed to −48 and 48° with 5.6 and 5.5 dBi realized gain in the xoz-plane and −48 and 48° with 2.9 and 3.0 dBi realized gain in the yoz-plane. Therefore, the proposed antenna is a good candidate for wireless communication systems.

A Low-Profile Antenna With Omnidirectional and Unidirectional Radiation Patterns Over Two Operation Bands

A compact low-profile dual-band antenna with a single circular radiation patch is presented. The circular radiation patch is top-loaded by a metal strip, leading to a zeroth-order resonant (ZOR) mode with monopole-like radiation pattern at the lower operation band, and the ZOR mode is not affected by the position change of the probe feed. Thereby an off-center probe feed can be used to excite a TM01 mode with patch-like radiation pattern at the upper operation band, and its performance remains good stability when the size of the metal strip is varying. The equivalent circuit, electric field and current distributions of the proposed antenna are studied to investigate the principles of the ZOR and the TM01 modes, and all the results show that the two operation bands can be effectively and independently controlled. As a proof-of-concept, a circular patch antenna prototype with low profile of about $0.023~\lambda _{0}$ at 2.35 GHz is fabricated and tested. Good agreements between the measured and simulated results are achieved, showing monopole-like and patch-like radiation patterns within 2.28 - 2.40 GHz and 3.30 - 3.60 GHz, respectively, and the average realized gains are about 2.5 dBi and 8.5 dBi for the two operation bands.

Four-Element Composite Triangular Dielectric Resonator Antenna Using Li2O-1.94MgO-0.02Al2O3-P2O5 Ceramic for Wideband Applications

A simulation and fabrication study of a coaxial probe-fed four-element composite triangular dielectric resonator antenna (TDRA) using low loss Li2O-1.94MgO-0.02Al2O3-P2O5 (LMAP) ceramic and Teflon. LMAP ceramic was carried out and the ceramic was synthesized using a solid-state sintering route. The phase, microstructure and microwave dielectric properties of LMAP were investigated using x-ray diffraction pattern, scanning electron microscopy and a network analyzer. A coaxial probe-fed four-element composite TDRA was designed and fabricated using LMAP as one section of each composite element of the proposed antenna. Each triangular element of the proposed dielectric resonator antenna (DRA) consists of two sections of different dielectric constant materials. The inner triangular section touching the coaxial probe at one of its corners is made of the LMAP ceramic (er = 6.2) while othe uter section is made of Teflon (er = 2.1). Four triangular DRA elements are excited bya centrally located 50-Ω coaxial probe. The parametric study of the proposed antenna was performed through simulation using Ansys High Frequency Structure Simulator software by varying the dimensions and dielectric constants of both sections of each triangular element of the TDRA to optimize the results for obtaining a wideband antenna. The simulated resonant frequency of 9.30 GHz with a percentage bandwidth of 61.65% for the proposed antenna is obtained within its operating frequency range of 7.82–14.8 GHz. Monopole-like radiation patterns with low cross-polarization levels and a peak gain of 5.63 dB are obtained for the proposed antenna through simulation. The antenna prototype having optimized dimensions has also been fabricated. The experimental resonant frequency of 9.10 GHz with a percentage bandwidth of 66.09% is obtained within its operating frequency range of 7.70–15.30 GHz. It is found that the simulation results for the proposed antenna are in close agreement with the measured data. The proposed antenna can potentially be used in broadcast base stations, radar and satellite communications.

A High-Isolation, Ultra-Wideband Simultaneous Transmit and Receive Antenna With Monopole-Like Radiation Characteristics

A high-isolation, ultra-wideband simultaneous transmit and receive (STAR) antenna with monopole-like radiation characteristics is presented. The proposed STAR antenna consists of a center-located monocone and a circular array of bent loops. The monocone and the array of loops are located in the near fields of each other and serve, respectively, as the transmit (TX) and receive (RX) antennas. To achieve omnidirectional, vertically polarized radiation patterns, the array factor of the bent loops is first examined. A circular top loading and four T-shaped parasitic elements are exploited to decrease the lowest frequency of operation of the antenna without increasing its occupied volume. Finally, based upon the analysis of the array factor, four directors are strategically mounted over the ground plane to enhance the omnidirectionality of the antenna in the azimuth plane. A prototype of the antenna operating in the UHF band is fabricated and measured. Experimental results demonstrate that the proposed STAR antenna achieves an isolation greater than 40 dB from 0.6 to 1.75 GHz (2.9:1 bandwidth). Furthermore, the STAR antenna is capable of maintaining consistent monopole-like radiation patterns and vertical polarization for both the TX and the RX channels across the entire band of operation.

A novel ACPW-fed quad-band hybrid antenna for wireless applications

This paper presents a novel asymmetric coplanar waveguide-fed quad-band hybrid antenna for wireless applications. The proposed hybrid antenna combines a conventional monopole antenna and a zeroth-order resonator antenna to perform a dual-mode operation. The first mode is generated by a slotted monopole antenna, supporting the two higher resonances at about 3.5 and 5.8 GHz. The second mode is supported by loading a composite right-/left-handed transmission line unit cell near the slotted monopole, contributing to the two lower resonances at about 1.6 and 2.5 GHz. It is printed on an FR4 substrate with the overall dimensions of 40 mm × 24 mm × 1.6 mm. Experimental results demonstrate that it can cover the global positioning system (1.57–1.59 GHz), wireless local area network (2.4–2.485, 5.15–5.35, and 5.725–5.825 GHz), and worldwide interoperability for microwave access (2.5–2.69, 3.3–3.7, and 5.25–5.85 GHz) applications with monopole-like radiation patterns and acceptable gains.