Monocone Antenna Research Articles

Исследование масштабного макета моноконической антенны диапазона средних волн

Terrestrial radio navigation systems keep playing a significant role in the radio navigation due to high jamming immunity in comparison to satellite global navigation systems. In this paper a monocone antenna for radio navigation in medium frequency band is considered. To confirm the performance of a supposed future full-size experimental setup, a scaled prototype model with 1/200 scale factor was developed. Computational simulation was carried out and it was shown that the scale factor value as well as some changes in model have a negligible effect on the reflection coefficient frequency response. Scale model of the antenna was fabricated of foiled laminates and measured. The results of reflection measurements are in good agreement with the simulation.

A Novel High-Isolation Dual-Band Monocone Antenna Array for Wi-Fi 6 Application

This paper presents a novel high isolation monocone antenna array for Wi-Fi 6 applications. Conical radiator, top patch and shorting pins are combined to obtain an ultra-wide operating bandwidth, which covers the full Wi-Fi 6 frequency bands. The decoupling structure consists of two parts: higher-frequency decoupling element (HDE) and lower-frequency decoupling element (LDE). LDE consists of a pair of C-shaped rings, a metal strip and three shorting pins. HDE is composed of two T-shaped metal strips placed vertically on the ground. For further investigation, the equivalent circuit model of the proposed antennas is adopted to explain the decoupling principles. And design formulas are rigorously derived to facilitate the construction of decoupling structures. For verification, a dual-band monocone MIMO antenna with edge-to-edge spacing of 0.1388 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (evaluated at lower frequency) is prototyped and characterized. The measured results reveal that proposed antenna can offer enhanced port isolation (23dB/40dB), increased antenna efficiency (>80%) and improved pattern diversity.

A Compact Ultra-Wideband Monocone Antenna with Folded Shorting Wires for Vehicle-to-Everything (V2X) Applications

In this paper, a capacitively-fed, ultra-wideband (UWB), and low-profile monocone antenna is proposed for vehicle-to-everything (V2X) applications. The proposed antenna consists of a monocone design with an inner set of vias. Additionally, an outer ring is added with a small gap from the monocone and shorted with six folded wires of different lengths to extend the operating band. The proposed antenna covers the frequency range from 0.75 GHz to 7.6 GHz and has a 164% fractional bandwidth, with a gain value varying between 2 and 10 dBi. The dimensions of the antenna are 0.37λL × 0.37λL × 0.067λL. The antenna was fabricated using a 3D printer with low-cost polylactic acid plastic (PLA) material and then sprayed with aerosol copper nanoparticles. The efficiency was approximately 90% throughout the frequency bands of interest. Finally, the proposed antenna was installed on a vehicle and tested with an OBU (onboard unit) and a RSU (roadside unit) in the field. The results show a longer wireless communication range for V2X applications.

Development and Research of a Medium Vertical Dipole Electromagnetic Pulse Simulator

In this paper, the design of a self-developed EMP simulator with a 5 m height and an inverted conducting mono-cone antenna with a cone half-angle of 32° is introduced. The experimental region of the simulator is a circular area of 25 m in diameter around the cone vertex. Two feeding modes, feed-in over the ground and feed-in under the ground, are realized by two different high-voltage pulse sources. It can be concluded through radiation field testing that the radiation field waveform generated by the simulator has a rise time of 2–3 ns and a half-width of about 25 ns, meeting the specifications of the EMP experimental waveform in the IEC61000-2-9 standard. Meanwhile, the differences between the engineering implementation of the simulator and its ideal structure during the design process can lead to some distortion issues in the antenna radiation characteristics and the electromagnetic radiation field it generates. The radiation field waveform and the distribution of the EMP field generated by the simulator under different feeding methods, antenna wire quantities, antenna end processing methods, and different antenna resistive loading were studied, and the changes in the radiation field waveform and field distribution with different angles and distances of the monitoring point were analyzed. Based on the measurement results, the radiation characteristics of the antenna and the factors that affect the waveform of the field were studied and analyzed. Through the aforementioned work, a comprehensive understanding of the performance, radiation characteristics, and engineering factors affecting the electromagnetic environment generated by the simulator has been obtained. On this basis, the parameters of the antenna wire quantity, antenna end processing method, and test point position of the designed simulator were reconfirmed and optimized. In summary, this work has important reference significance for mastering the development technology of such simulators, understanding their antenna radiation characteristics, and conducting EMP-related assessments and effect experiments in the future.

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.

A wideband parallel‐plate waveguide design for FSS/FSR measurement

In this letter, a parallel-plate waveguide (PPW)-type transverse electromagnetic (TEM) transmission chamber covering 2–14 GHz is designed, analyzed, and fabricated, which consists of a feed structure and two metal cover plates. The feeding structure is made of a structure similar to a monoconical antenna, with a good impedance bandwidth. To reduce the edge radiation of the PPW structure, the TEM wave cell (TEM cell) is surrounded by absorbing foam. Moreover, to verify the testing effect of the designed TEM cell, a simple square frequency-selective surface was tested in the TEM cell. The test results are in good agreement with the simulation results. It has been shown that the designed TEM cell can be used as an effective supplement to the transmission reflection test method for periodic structures.

A miniaturised mono‐cone antenna with top plate and composite lumped loading

A wideband mono-cone antenna is proposed. Evolution from a top-loaded mono-cone, the top plate is etched by two rings and loaded by an array of resistors and inductors. This design improves impedance matching properties in the low frequency range while maintaining a compact size. An equivalent circuit modal is built for assisting the antenna design. A prototype is fabricated and measured for verification. The antenna operates in the frequency band of 118–1100 MHz with |S11|≤-10 dB and the fluctuation of omni-directional radiation pattern ≤ 2.5 dB. The occupied area of the antenna is 0.24 λL × 0.24 λL × 0.06 λL, which is attractive for use on aircraft.

A Wideband Monoconical Antenna for Airborne Applications With a Null-Filled Radiation Pattern

A wideband monoconical antenna with a null-filled radiation pattern for airborne applications is presented. A rotating current distribution, which radiates an electric field at the null point (<i>&theta;</i> &#x003D; <i>&phi;</i> &#x003D; 0&#x00B0;) of an omnidirectional radiation pattern of a conventional monoconical antenna, is formed using the proposed slotted structure in a monoconical radiator. In the proposed design, the null point is effectively filled over the 1:12 impedance-matched frequencies, while the size of the reference monoconical antenna is maintained. A figure of merit composed of the electric field intensity in the main radiation area (0&#x00B0; &#x2264; <i>&theta;</i> &#x2264; 45&#x00B0; and 0&#x00B0; &#x2264; <i>&phi;</i> &#x2264; 360&#x00B0;) and the profile of the antenna shows that the proposed antenna performs better than a conventional monoconical antenna or a fan-dipole antenna used in airborne applications. The impedance and radiation performances of the proposed antenna are verified experimentally from a 5.85:1 scaled built prototype.

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.

Compact monopole antenna for wireless body area network, wireless local area network, and ultrawideband applications

In this paper, a wearable ultra-wideband (UWB) monopole antenna with a compact structure and low profile is presented for wireless body area networks, wireless local area networks, and UWB applications. The antenna is composed of three triangular radiators on the basis of the mono-cone antenna. By the methods of reactive and slot loading, the dimension of the antenna can be greatly reduced. The overall height of the antenna is 0.06 λ0 at its lowest operating frequency. The radiated structure of the proposed antenna with the dimension of 31 × 31 × 9 mm3, which operates in 2.3 to 12.6 GHz, is fabricated and the measurement results are in good agreement with the simulated ones. Moreover, the influence of the human tissue on the antenna was evaluated, and stable performance can be obtained on the human tissue under different bending conditions. The specific absorption rate values are lower than the limitation set by the European Telecommunications Standards Institute, which indicates that the antenna is suitable for wearable applications.

Design and Analysis of Modified UWB Mono-Cone Antenna for WBAN Applications

A low-profile UWB antenna is presented in this paper for wireless body area network (WBAN) applications. The proposed antenna consists of a modified mono-cone structure by adding a semi-sphere on top of the mono-cone. A top-plate is added as overhead to the proposed antenna. This plate leads to a height reduction when compared to conventional mono-cone antennas. In this paper, the effect of ground plane dimensions, effect of top-plate dimensions, effect of the supporting legs and effect of the total height of the antenna is studied to get a better insight into the working of the radiating structure. The antenna operates in the frequency range of 4.1 GHz to 10.1GHz with return loss less than -10dB. The bandwidth of the proposed antenna is 6 GHz. The frequency domain results are obtained by simulating the design using Ansoft HFSS. The voltage standing wave ratio is less than 2 within the frequency range of the proposed antenna design. The influence of the human proximity on the antenna was simulated by placing the proposed antenna over a human body model.

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.

Low-Profile and Small Monocone Antenna Composed of a Circular Plate and Three Oblique Short Elements

Low-Profile and Small Monocone Antenna Composed of a Circular Plate and Three Oblique Short Elements

A Superwide Bandwidth Low-Profile Monocone Antenna With Dielectric Loading

A dielectric-loaded low-profile monocone antenna with vertical polarization and omnidirectional radiation is proposed to cover a superwide frequency bandwidth for some emerging wireless communication applications. The extended bandwidth is achieved by using four quasi-TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0N</sub> modes (N from 1 to 4) and introducing the dielectric loading (DL) with optimal design. The DL can effectively change the impedance response of the monocone antenna and provide additional degree of freedom for increasing the bandwidth. The proposed antenna is designed, fabricated, and tested to verify the antenna's performance. The designed and fabricated antenna with a thickness of only 0.057 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">low</sub> can achieve a superwide impedance bandwidth of 7.3:1 (from 1.6 to 11.7 GHz).

A Low-Profile Wideband Monocone Antenna Using Bent Shorting Strips

A low-profile wideband monocone antenna with bent shorting strips, and parasitic and circular sleeves is proposed. By loading the bent shorting strips, parasitic sleeves, and circular sleeves, miniaturization of the antenna is achieved. Along with bent shorting strips from the monocone hat to the ground plane, parasitic sleeves, and circular sleeves are mounted to enhance the impedance bandwidth. From the experimental results, the –10 dB reflection coefficient bandwidth of the proposed antenna ranges from 810 MHz to 5340 MHz. In addition to the wide bandwidth characteristics, the proposed antenna has highly desirable omnidirectional radiation properties for wireless communication systems.

A 3D-Printed Tapered Cavity-Backed Flush-Mountable Ultra-Wideband Antenna for UAV

A tapered cavity-backed flush-mountable dual mono-cone antenna is proposed. The proposed antenna consists of four main sections: a lower mono-cone, an upper mono-cone, novel feeding structures, and an exponentially tapered cavity. To obtain high-frequency band operation, the upper mono-cone excited by the feeding structures is located inside the lower mono-cone. The circular cavity used in the proposed antenna has a tapered wall for mitigating the deterioration of radiation performance. The proposed antenna has overall dimensions of 200 mm × 200 mm × 30 mm. The measured reflection coefficients (S-parameters) are below -10 dB from 1.43 GHz to 39.05 GHz (1:27.3). The measured radiation pattern has a quasi- omnidirectional characteristic in the operating frequency band.

Broadband Full-Duplex Monostatic Circular-Antenna Arrays: Circular Arrays Reaching Simultaneous Transmit and Receive Operation

Broadband copolarized monostatic circular-antenna arrays based on mode orthogonality principles are presented for in-band full-duplex (FD) applications. The simultaneous excitation of circular phase modes in a circular array with four elements provides ideally infinite isolation. However, once the realistic beamformer network (BFN) is used, the isolation between the transmitter (Tx) and receiver (Rx) is reduced and becomes bound by the internal leakages. To mitigate the undesired leakages, two possible configurations are demonstrated: 1) a single-layer (SL) circular array excited simultaneously with mode 1 (M1) at the Tx and mixed modes at the Rx, and 2) a dual-layer (DL) circular array excited with M1 at the Tx and mode 0 (M0) at the Rx. The arrays are prototyped, in which each SL array is made of four broadband monocone antennas. A measured voltage standing wave ratio (VSWR) l2 and average isolation of 45 dB for a SL array more than at least an octave bandwidth, and 35 dB from 0.8 to 1.3 GHz and 45 dB more than 1.3 GHz for the DL array are obtained. A simple isolation enhancement layer is integrated with the shared BFN to recover from the imbalances and asymmetric leakages with an isolation improvement of up to 50 dB more than a 2.8-MHz tuneable bandwidth. The envelope correlation coefficient (ECC) is used to quantify the similarity between circular Tx/Rx array modes, and the ECC g0.6 for M1 Tx/mixed-modes Rx and g0.75 for M1 Tx/M0 Rx are achieved.

Antenna Systems for Simultaneous Transmit and Receive (STAR) Applications

Abstract Several novel wideband co-polarized circulator-less monostatic antenna and array designs for co-channel simultaneous transmit and receive (STAR) applications are presented. The monostatic STAR apertures are demonstrated first by utilizing multi-arm spiral antennas where a set of arms is used for transmitting (TX) and the other set for receiving (RX). Then, square and hexagonal broadside STAR arrays utilizing closely-spaced spiral antennas are introduced. Finally, (quasi) omnidirectional circular STAR arrays based on phase modes orthogonality principles are realized using four wideband monocone antenna elements. The studied configurations are integrated with the proper beamforming networks to excite the desired modes of TX/RX operations leading to theoretically infinite isolation between TX and RX ports. Practically, the achieved isolation is limited by the electrical asymmetries of the used components. Overall, consistent wideband operation, high isolation, and decent far-field performance are achieved for all proposed STAR approaches.

Mutual Coupling Mitigation in Broadband Multiple-Antenna Communication Systems Using Feedforward Technique

An efficient method to mitigate the forward scattering (shadowing) effect and the near-field coupling among elements of broadband multiple-antenna communication systems is proposed. The technique is based on provision of a passive feedforward coupling among elements to cancel out the mutual couplings. Electrical current paths, with appropriate shape, location, and length, between adjacent elements are established to provide current distributions on adjacent elements that are approximately equal in magnitude and out of phase with the induced current on the same antenna due to the near-field coupling and scattering effects. As the coupling level decreases, the radiation pattern of an excited array element, in the presence of the other array elements, approaches the pattern of the antenna element in isolation. The technique is first detailed for a two-element wideband monoconical antenna array and is then extended to a uniform 12-element circular array of the same monoconical antennas where only feedforward paths are applied to circumferentially adjacent elements to reduce the coupling over a very wide bandwidth. The experimental results indicate that the application of the proposed feedforward technique to a 12-element circular array of monoconical antennas can provide a minimum of 2-dB reduction in the average gain deviation from omnidirectional radiation over an about 30% fractional bandwidth. Another important feature of the feedforward technique is removal of radiation nulls of the array elements at all frequencies and all directions.

Miniaturization of Ultrawideband Monocone Antennas Using Dielectric Loading

A so-called intelligent approach for miniaturization of monocone antennas using dielectric loading is presented. Two impedance mismatches causing the degradation in impedance bandwidth due to high permittivity dielectric loading are identified. The input impedance mismatch is addressed by modifying the structure of the antenna feed. Adding a spatial quarter-wave transformer matches the wave impedance of the loading region to that of free space. The feasibility of such a loading scheme is validated by effectively miniaturizing a monocone antenna with a material of ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 9.0. Simulations show the diameter of the ground plane is reduced by 55.2%, while the miniaturized monocone has a relative impedance bandwidth of 106.3%. The proposed dielectric loading concept is further applied to miniaturize three other monocone antennas to show its generality. In addition, the feasibility is further validated through miniaturization of monocone antennas using dielectric materials of various permittivity values. Finally, a miniaturized monocone antenna using a dielectric material of ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 9.0 is fabricated and measured to experimentally verify and validate the concept.