Conical Beam Antenna Research Articles

A conical beam antenna array with filter characteristics for multi-rotor unmanned aerial vehicle measurement system

ABSTRACT This paper proposed a novel filter antenna with the conical beam, which consists of four magnetoelectric (ME) dipole antennas. By printing parasitic patches and etching open slots on the bottom of the substrate, two radiation nulls near the high frequency of the passband are introduced. Combined with the intrinsic radiation null of the ME-dipole antenna, the filtering response is obtained. In order to verify the design method, a prototype is manufactured and measured. The measurement results show that the impedance bandwidth (VSWR <2) of the antenna is 1.48 ~ 2.61 GHz (55.3%). In addition, the out-of-band suppression is more than 17.4 dB and the maximum radiation direction of the conical beam is stable around to Theta = 30°. The proposed antenna array can be promising candidates for multi-rotor unmanned aerial vehicle (UAV) measurement systems.

Broadband Polarization-Decoupled Metasurface for Generating Tailored Dual-Polarization Conical Beams

Conical beam antenna plays a significant role in providing stable access to satellite signals for moving communication terminals. Although metasurfaces have been used to generate conical beams, most of them can only reflect conical beams with identically distributed and mirror-symmetric phase responses for left-hand circular polarization and right-hand circular polarization, which can hinder the dual-polarization applications of metasurfaces. In this study, a metasurface is designed to independently manipulate dual-polarized excitations in broadband. To achieve the broadband control of conical beams, broadband conditions for both geometric and propagation phases are developed. Differently, metasurface designed in this study consists of three types of distinguishingly shaped elements, which can provide more degree of freedom in dual-polarization broadband design. In addition, a design method is developed for metasurface to generate the cone angle tailorable conical beams. Via fabricating a metasurface following the proposed method, the designed metasurface is verified in theorem, simulation, and experiment that it can generate desired conical beams with tailored divergent angles and phase responses covering a bandwidth from 12.5 GHz to 17 GHz.

A Broadband Gain-Enhanced Conical-Beam Antenna Loaded With the Multicircle Sectored Metasurface

A broadband gain-enhanced monopole antenna loaded with metasurface is designed in this paper, which is suitable for sub-6 GHz fifth-generation (5G) applications. The multi-circle sectored metasurface antenna is analyzed through the evolution process and field distribution. With the addition of the metasurface, the antenna’s relative bandwidth is increased from 23.25% to 48.5%, and the in-band gain is improved by 2 dBi. To validate the proposed working principles and design guidelines, the proposed antenna is fabricated and measured. Measured results agree well with the simulated ones and show that the -10 dB impedance bandwidth is 56% (3.25-5.78 GHz), covering the 5G frequency band (3.3-3.6, 4.8-5 GHz). The average gain in the desired band is 7 dBi with a variation of ±1 dBi, which is suitable for 5G indoor micro ceiling base station applications.

High‐gain ultra‐wideband quasi‐conical beam Fabry‐Perot antenna based on beam switching

To solve the contradiction between the high gain and wide coverage, the concept of the quasi-conical beam is proposed by using the high-gain pencil beam electrically switching along a cone to make full use of time redundancy. In a periphery-fed Fabry-Perot (FP)-type multi-beam antenna, the electrically switching is used to activate the different port corresponding to the different beam for the beam switching in the azimuthal plane, and the varying frequency is used for the continuous scanning in the elevation plane. Different from the lens or matrix multi-beam arrays, in this scheme, the FP cavity serves as both the beamforming network and the radiator to produce the multi-beam. Around eight planar antipodal Fermi-tapered slot antennas are placed around the FP cavity between the partially reflective surface and the metal ground plane as the primary feeds. The simulation and measurement results show that a relative impedance bandwidth of 53.3% with reflection coefficients below −10 dB from 11 to 19 GHz is obtained and the peak gain is 17.1 dBi at the central frequency of 15 GHz. The results also show that a high-gain beam scanning from 22° to 59° in the elevation plane is achieved and the peak gains are between 16 dBi and 20 dBi. In addition, when the electrically switching of the beam is along a cone, the proposed antenna may form quasi-conical beam. And in some applications, it may replace the conventional conical beam antenna with the advantages of wide coverage and high gain.

A Fabry–Perot Conical Beam Antenna With Multi-Polarization Reconfigurable Capability

In this communication, a Fabry–Perot (FP) conical beam antenna with multipolarization reconfigurable capability is proposed. A single-layer partially reflective surface (PRS) with circular slots is designed for the prescribed flare angle determined by the height of the FP antenna and resonant frequency. A group of Vivaldi patches with a set of shorting vias around a common central axis on a printed circuit board (PCB) are used as the primary source, which is fed by nested coaxial waveguide. Vivaldi patches coupled with parallel baluns, which are connected to the internal coaxial waveguide, are used to produce a horizontally polarized conical beam. A vertically polarized conical beam can be obtained when the external coaxial waveguide is used to feed the Vivaldi patches. When circularly polarized conical beams are required, the internal and external coaxial waveguides need to be excited at the same time with the same amplitude and the proper phase difference. A prototype of the proposed FP conical beam antenna with multipolarization reconfigurable capability at 12 GHz is designed, fabricated, and measured to verify the concept. The measured results are in good agreement with the simulated ones. A maximum gain of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\ge 12.8$ </tex-math></inline-formula> dBic is achieved with the proposed FP conical beam antenna for the two circular polarization states, with an axial ratio (AR) and impedance bandwidth (IBW) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\ge 16.7$ </tex-math></inline-formula> % and 8%, respectively. The maximum gain and IBW for the horizontal polarization (HP) and vertical polarization (VP) are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&gt;13.2$ </tex-math></inline-formula> dBi and 9.2%, respectively.

A Conical Beam Antenna Using a Monopole Wire and Rectangular Copper Probe with Four Parasitic Sleeves for UMTS/WLAN Applications

This paper aimed to present a wideband monopole antenna for base station applications of indoor reception for UMTS (B1) and WLAN (IEEE 802.11b) systems. The operating frequency was ranged from 1.92 GHz to 2.5 GHz. The proposed antenna was made up of a probe and four connecting parasitic sleeves from the upper copper circular patch to the ground. The rectangular probe structure technique was used to extend the frequency band and effectively improve the matching conditions. The results from simulation and measurement showed that the presented antenna had a proper matching impedance of |S11| (dB) lower than -10 dB in the frequency band from 1.71 GHz to 3.72 GHz and also from 1.58 GHz to 2.98 GHz, respectively. The percentage of bandwidth was 74.03% and 61.40%, respectively. The antenna had a conical radiation pattern. The simulated and measured gains were 2.93 dBi to 3.6 dBi and 2.58 dBi to 3.54 dBi, respectively.

A Transmitarray Illuminated by a Pencil Beam Source to Obtain Conical Beam With Fixed Linear Polarization and Circular Polarization

A linear polarization matching with fixed linear-polarized conical beam antenna has the superiority in some applications compared with the radially linear-polarized conical beam antenna. In this communication, a transmitarray illuminated by a pencil beam source to obtain conical beam with fixed linear polarization (FLP) is presented. The pencil beam source is also used to obtain the conical beam with circular polarization (CP). To achieve good circumferential symmetry, the transmitarray elements are distributed on rings. And the dimensions of the double-ring elements on the surface of the transmitarray are adjusted to compensate for the phase delay of the wave from the horn phase center and form a desired phase distribution on the transmitarray aperture. Based on this mechanism, three different cone angles of the FLP conical beam transmitarray are designed. A transmitarray illuminated by a horn to obtain conical beam with the radius of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.25\lambda $ </tex-math></inline-formula> has been designed and fabricated. The simulated results show that its gain is higher than 9 dBi at the designed frequency 12.5 GHz with a cone angle of 40°. Measured results agree reasonably well with the simulated ones. The conical beam antenna with CP has also been simulated and designed using the circular polarized feed source illumination.

To tailor the conical beam by using planar superstrate

Here, the planar superstrate is used to tailor the conical beam. In the applications of conical beam antenna, making a good balance between the wider coverage and the higher gain is always a challenge, while the planar superstrate provides the freedom of design. Through adjusting the parameters of the planar superstrate, it is possible to change the coverage range and to make the beam more flat. To verify the proposed method, some simulated results are presented and two prototypes with homogeneous dielectric slab superstrate and with patterned dielectric slab superstrate are fabricated and measured. The simulated results and the measured ones are in good agreement.

Low‐profile ring slot SIW antenna based on higher‐order cylindrical cavity modes

A novel ring slot substrate-integrated waveguides (SIW) antenna is presented based on higher-order cylindrical cavity mode. First, TM02 is used to realise a conical beam antenna. Electric field distribution on slot aperture generates four pairs of magnetic monopoles, each rotated 90° with respect to the centre of the cavity, resulting in a conical beam. By applying an offset to the feed point, the loading effect of slots generates a hybrid mode, which is a combination of TM31 and TM12. The hybrid mode aligns the magnetic monopoles; thus, a high-gain antenna with broadside radiation can be realised. The measured results show a 10.5% impedance bandwidth, 11.5 dBi gain, and 90% radiation efficiency. The proposed antenna is low-profile and compact with a planar structure that could be integrated with other planar circuits; therefore, it could have many practical applications in communication systems.

Fixed‐frequency conical beam scanning antenna array with small ripple for Satcom‐on‐the‐Move system

AbstractA conical beam antenna array with fixed‐frequency scanning capability is proposed. Twelve open waveguide radiating elements filled with microwave ferrite on a metal ground plane are evenly distributed around a circle to realize small gain ripple and the array is fed by a planar feeding structure to realize low profile. The fixed‐frequency beam scanning can be realized by varying the magnetic bias field applied perpendicularly to the width of the waveguide. The coupled lines with two shorts are utilized to realize the high characteristic impedance. The measured results show that the conical beam scans from 13° to 31° at the center frequency and the gain is better than 8 dBi. The ripple is less than 0.5 dB. Good agreement has been observed between the simulated results and the measured ones.

Synthesis of concurrent multibeam and conical beam antenna arrays

An approach is presented to synthesize linear and planar antenna arrays to have concurrent multibeam radiation patterns as well as desired sidelobe levels. This approach is based on zeros perturbation of the pattern of linear arrays. Multibeam planar arrays are synthesized by both multiplying and transforming multibeam linear arrays. Besides, planar arrays having conical or ring type beam are synthesized by applying a special transformation to dual-beam linear arrays. Some examples are brought to verify the effectiveness of the proposed approach for both linear and planar arrays.

Topology Optimization of Conical-Beam Antennas Exploiting Rotational Symmetry

Microstrip conical-beam antennas are designed by the topology optimization of metallic patches combining the discrete optimization of vias. The antennas are designed to be angular-periodic structures with eight identical sectors, which makes the rotational symmetric radiation pattern more easily to be achieved and the optimization problem much easier to be solved. A restarting technique is introduced for the circular polarization design case, where the high cross-polarization discrimination (XPD) is hard to be realized. By increasing the weight of cross-polarization penalization function after the optimization restarts, much higher XPD is achieved compared to that of the antennas optimized with fixed subobjective weighting factors. By this method, two conical-beam antennas, which are linearly polarized and left-handed circularly polarized antennas, respectively, are designed. Simulated and measured results show that the antennas have expected conical shape radiation patterns, good matching, and high polarization purities.

Broadband conical beam antenna in planar environment

In this article, a substrate-truncated microstrip circular patch antenna with shorting vias is proposed for X-band applications. The bandwidth of the designed antenna is substantially increased by making two slots—one circular and another annular ring—at the top of the structure which actually helps in bringing two individual resonating frequencies closer to each other. The antenna is simulated using the Ansoft HFSS, and various parameters are optimized for better performance. The deigned structure is finally fabricated and tested, and the measured data fairly agree with the simulated results. The measured relative impedance bandwidth (|S11| < −10 dB) is found to be 28.5% (8.9-11.85 GHz). The proposed antenna is behaving like a monopole with the radiated beam of conical shaped in the entire operating band having a maximum gain of 7.2 dBi.

Truncated Circular Cone Slot Antenna Array That Radiates a Circularly Polarized Conical Beam

A truncated circular cone slot array antenna that radiates a circularly polarized (CP) conical beam is presented. The direction into which the conical beam radiates depends mainly on the tilt angle of the outer conductor as well as the proper arrangement of the positions of its two slot arrays. The CP property is realized by introducing quasi-perpendicular slots that are cut into the outer conductor of a truncated circular cone. To illustrate the performance characteristics of this CP conical beam antenna, the tilt angle is set to 45° and the beam angle is pointed at 45° from boresight within the operating band. A prototype was fabricated and tested. The measured results demonstrate that its −10 dB impedance bandwidth ( $\vert S_{{11}}{\rm{\vert \, dB) is 720 MHz, from 5.05 to 5.77 GHz; and its 3 dB axial-ratio (AR) bandwidth is 500 MHz, from 5.5 to 6.0 GHz. Its realized gain over this AR bandwidth ranges from 4.84 to 5.8 dB. The designed beam direction can be easily changed to meet specific application requirements. Moreover, it can be readily reconfigured to be a conformal antenna mounted on the top of a high-speed mobile platform.

High Gain Conical Beam Antenna Array Exploiting Grating Lobes

The alternative solution is presented for single- and multi-ring arrays with a high-gain and wide elevation coverage conical beam. Effects of ring radii, number of elements, beam switching and multi-ring operation are analyzed using array theory. Gain enhancement at the large flare angle is obtained by using grating lobes of the array factor with conical pattern elements. The switching technology is employed to improve pattern ripple in azimuthal plane and to exploit the grating lobes for achieving high gain. Excitations of all the elements are in phase. A prototype of a single-ring array with 13 elements has been fabricated and measured. Three sub-arrays each composed of four elements are arranged on the ring and the other single element is located at the center. Measured results show that elevation beam coverage is from 20° to 55° and the maximum radiation gain is 9 dBi at 48° elevation at 12.5 GHz.

Circularly Polarized Conical-Beam Antenna With Wide Bandwidth and Low Profile

This work introduces a circularly polarized (CP) conical-beam antenna with low profile and wide impedance & axial ratio (AR) bandwidths. The antenna structure simply consists of a wideband monopolar patch antenna and eight parasitic loop stubs for generating vertically polarized electric field Eθ and horizontally polarized field Eφ, respectively. The proposed antenna is low profile but wideband because of merging the TM01 and TM02 modes at around the center frequency. In order to obtain the wideband CP radiation, the eight parasitic loop stubs are printed and placed sequentially along the radiating edge of the patch. With the resultant radiations from both the patch antenna and the loop stubs, the CP conical-beam radiation pattern can be obtained. In addition, a parametric study of the shorting vias effect, number of loop stub elements, and loop widths are demonstrated how to design this wideband CP antenna. The antenna exhibits the wide impedance bandwidth of 28% from 4.9 to 6.5 GHz (for the reflection coefficient ≤ -10 dB) and the 3-dB AR bandwidth of 14.4% from 5.8 to 6.7 GHz. The thickness of this antenna is only 0.06λ in terms of the free-space wavelength at its lowest operation frequency. Stable omni-directional conical-beam radiation patterns are observed over the operating bandwidth with the peak gain of 4.9 dBic. The antenna can cover the uplink of standard C band (5.85 to 6.425 GHz) for satellite communication.

CONICAL BEAM WINDMILL-SHAPED ARRAY ANTENNA DESIGN BASED ON QUARTER-MODE SUBSTRATE INTEGRATED WAVEGUIDE

This paper presents a compact conical beam antenna based on quarter-mode substrate integrated waveguide (QMSIW). The antenna array is consisted of six isosceles right-angled triangle metallic patch printed on the upper side of the substrate in a windmill-shape and diagonal periodic metallic via holes drilled along the hypotenuse of the triangle patch. The planer structure exhibits conical beam radiation. The typical radiation is obtained at 5.2GHz with conical beam radiation pattern. The measured gain is about 5.36dBi and the radiation e-ciency is around 50%.

A Wideband, Low-Profile, Conical-Beam Antenna With Horizontal Polarization for Indoor Wireless Communications

A novel, horizontally polarized, conical-beam antenna is proposed. The antenna is low in profile (H = 0.1867lambda <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> ) and has about 38% impedance bandwidth (SWR < 2) and average antenna gain of 5 dBi. The radiation patterns are stable across the operating band. Good agreement between simulated and measured results is observed.

A new design of horizontally polarized and dual-polarized uniplanar conical beam antennas for HIPERLAN

It is shown that a conical beam 5.2-GHz antenna suitable for HIPERLAN application, but working in horizontal polarization, can be realized as a group of microstrip patch radiators in a ring formation. Layouts with three and four patches are described, and radiation patterns are found to agree well with predictions from a simple array model. The three-patch form is smaller and gives a closer approximation to an azimuth-independent pattern. Patterns are very similar to those achieved in vertical polarization with previously reported disk antenna realizations, giving peak radiation at about 50/spl deg/ elevation. Two methods of impedance matching are found to give satisfactory results. A dual-polarized conical-beam microstrip antenna, with a strictly uniplanar conductor pattern, is also presented and realized as an array of three square patches whose corners meet a central feed point. For the second polarization, the antenna functions as a series fed array. Fairly good conical beam patterns have been obtained, though only moderate polarization purity appears to be obtainable from three-element arrays.

A Conical Beam Antenna using a Probe Excited Hemispherical Loop on the Ground Plane

A Conical Beam Antenna using a Probe Excited Hemispherical Loop on the Ground Plane