Monopole-like Radiation 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 Single-Layer Low-Profile Broadband Metasurface-Inspired Antenna With Monopole-Like Radiation Characteristics

This communication presents a novel single-layer, low-profile broadband metasurface (MTS)-inspired antenna with monopole-like radiation characteristics. To excite symmetric surface waves (SWs) propagating along an MTS consisting of an array of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times4$ </tex-math></inline-formula> metal square patches, a horizontal center-fed monopole structure is used at the center of the MTS. The proposed antenna is further embedded within a square ring to improve the gain and H-plane patterns roundness at the upper-frequency band. The presented antenna achieved a −10 dB bandwidth of 32.62% (5.08–7.06 GHz) and a low profile of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.06\lambda _{0}$ </tex-math></inline-formula> ( <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> is the free space wavelength at the center of the operating band) distinctive features due, respectively, to the effective excitation of different TM SW resonant modes that are close to each other and the in-phase reflection property of the MTS. The planar structure, single-layer, and low-profile merits make the proposed antenna an ideal candidate for various wireless communications systems, such as wireless local area network (WLAN) at 5.2/5.8 GHz, WiMAX at 5.5 GHz, and car to car (C2C) at 5.85–5.925 GHz.

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.

Substrate integrated waveguide (SIW) cavity-backed slot antenna with monopole-like radiation for vehicular communications

Substrate integrated waveguide (SIW) cavity-backed slot antenna with monopole-like radiation for vehicular communications

Wideband Dielectric Resonator Antenna With Dual Circular Polarization

In this communication, two wideband dual-polarized dielectric resonator antennas (DRAs) for X-band radar applications are presented. The design procedure is started with designing a linear polarized DRA fed by a microstrip line. The feedline is optimized to excite the hybrid electromagnetic (HEM) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{11 \delta }$ </tex-math></inline-formula> modes of DRA which corresponds to magnetic monopole-like radiation. Then, a novel quadrature hybrid is designed in the feeding structure to provide both left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). Finally, two antenna prototypes are fabricated and tested: a dual (right hand and left hand) circular polarization DRA with omnidirectional pattern and an enhanced gain version of dual-polarized circular polarized (CP) DRA with a directive pattern. The measurement results of antennas confirm wideband impedance bandwidth (34% and 38.8%) as well as wideband axial ratio (AR) ones (23% and 30%) in element and array structures, respectively. The antennas also provide both RHCP and LHCP radiation. The first antenna contains monopole-like radiation which is aimed at wireless systems with omnidirectional pattern requirements. The second antenna, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 1$ </tex-math></inline-formula> antenna array, presents around 9 dB across the entire band. The presented antennas are good candidates for radar applications such as weather monitoring, air traffic control, and vehicle speed detection.

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 Low-Profile Wideband Antenna With Monopolelike Radiation Characteristics for 4G/5G Indoor Micro Base Station Application

A wideband, low-profile, vertically polarized antenna with monopolelike radiation characteristics is proposed for 4G/5G indoor base station applications. The design of this antenna is based on the traditional monocone antenna with internal matching and reactive load. The structure of monocone is realized by crossed substrate, which reduces the antenna weight and improves the design flexibility simultaneously. Then, reactive loading of capacitively coupled triangle patches and shorting pins are used to reduce the height of antenna profile to 0.08 λ min, where λ min is the free-space wavelength at the lowest operation frequency. An interdigital capacitor is etched near the antenna's input to adjust the impedance matching. The proposed antenna demonstrates consistent monopolelike, omnidirectional radiation patterns within the operating band. A measured impedance bandwidth for voltage standing-wave ratio (VSWR) < 2.2 of about 81% ranging from 1.66 to 3.95 GHz is achieved, which covers 1.7–2.7 GHz 4G Long-Term Evolution band and 3.3–3.8 GHz 5G N78 band simultaneously. The proposed antenna is tailored for the ceiling micro base station in indoor distributed system.

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.

A Conformal Band-Notched Ultrawideband Antenna With Monopole-Like Radiation Characteristics

A conformal, planar, and low-profile ultrawideband antenna with monopole-like radiation and band-notched characteristics is presented. A circular patch shorted to the ground is combined with two rectangular slots and two concentric rings, to achieve an ultrawide bandwidth from 3.8 to 8.3 GHz with a single rejection band from 5 to 6 GHz. The monopole-like radiation features, generated by combining TM $_{01}$ and TM $_{02}$ operating modes of a circular patch antenna, are maintained over the entire operating bandwidth. The antenna has only 0.046 $\lambda _{o}$ height at 3.8 GHz and is realized using polydimethylsiloxane conductive fabric composite technology making it highly flexible and physically robust. This was validated through severe bending tests with various curvatures.

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.