Bow-tie Antenna Research Articles

Exact theory and approximations for optical resonators in a changing external medium

Finding reliably and efficiently the spectrum of the resonant states of an optical system under varying parameters of the medium surrounding it is a technologically important task, primarily due to various sensing applications. Computationally, it presents, however, a fundamental challenge owing to the nature of the eigenstates of an open system lacking completeness outside it. We solve this challenge by making a linear transformation of Maxwell's equations which maps perturbations of the surrounding medium onto effective perturbations within the system where the resonant states are complete. By treating such perturbations with a rigorous resonant-state expansion, we find the modified modes of the system for arbitrary homogeneous perturbations of the medium with any required accuracy. A numerically efficient single-mode approximation is shown to be highly accurate, as illustrated for various plasmonic nanoparticles, including gold nanospheres and silver bowtie antennas.

A room-temperature, low-impedance and high-IF-bandwidth terahertz heterodyne detector based on bowtie-antenna-coupled AlGaN/GaN HEMT

In this paper, a 330 GHz terahertz heterodyne detector based on bowtie-antenna-coupled AlGaN/GaN high-electron-mobility transistor (HEMT) is designed and demonstrated. The bowtie antenna and a silicon lens couple the terahertz wave into a transmission line, in which the HEMT's channel generates both self-mixing and heterodyne signals. Compared to field-effect detectors without front low-noise amplifiers and output impedance matching, this detector boosts the intermediate-frequency (IF) bandwidth to 2.9 GHz due to a low output impedance of 505 Ω while maintaining a comparable sensitivity. With further sensitivity enhancement, such detectors would be developed into room-temperature, high-sensitivity, and high-IF-bandwidth heterodyne arrays.

변형된 접지면 구조를 이용한 대역폭 확장 특성을 갖는 보우-타이형 준-야기 안테나

In this paper, a bow-tie quasi-Yagi antenna with a modified ground plane structure is proposed for wideband characteristics. The ground plane structure of the proposed antenna improved the impedance-matching characteristics by inserting a parallel plate ground with a width equal to the parallel-coupled feed line width. This simply modified ground plane structure can lead to an improvement in impedance matching by additional inductance, capacitance, mutual inductance, and mutual capacitance components. The proposed antenna has a −10-dB reflection coefficient fractional bandwidth of 30 % and a realized gain of 7.7 dBi at the center frequency.

Inhomogeneous lens design to increase the gain of antennas regardless of the specific focal point.

In this paper, an inhomogeneous lens is presented based on the ray inserting method (RIM). The focal length is a critical issue in designing kinds of lenses. Usually, the focal point of the lens should be located at the feed phase center. The proposed lens is useful for an array of radiators and antennas without a certain phase center. Also, it can be used for broadband antennas because their phase centers are naturally dispersive. An inhomogeneous lens is designed beside a broadband rounded bow-tie antenna. The proposed lens can be used in millimeter, terahertz, and optical frequencies. The parametric model has been considered based on design frequency. The designed lens proposed a good match to the feed antenna and the surroundings. The designed lens is realized with the perforated cells. The full-wave simulations using CST software confirm the results at the operation frequency.

Design of Bowtie Antenna With Rounded Edge and Middle-Sliced Modifications for UHF Partial Discharge Sensor

Partial Discharge (PD) detection using ultra-high frequency (UHF) method has been proven as more noise-resistant in GIS condition monitoring, compared to the conventional PD detection methods, where the common noise frequency range such as in the power plants is below UHF frequency range. However, noise in UHF range may occur at certain conditions. Thus, UHF sensor with high sensitivity is necessary to detect PD-induced electromagnetic wave in UHF range. This paper discusses the modified design of a bowtie antenna as UHF sensor and its performance in detecting PD in the air. The modification method is conducted through simulation using antenna design software, resulting in curved-edge and middle sliced bowtie antennas. The designed bowtie antenna has wider bandwidth of above 300 MHz, reflection coefficient lower than -10 dB, and the voltage standing wave ratio (VSWR) less than 2. During initial design, the antenna geometry including gap distance, wing radius, and flare angle are adjusted to obtain the optimum antenna characteristics. The final designed sensor is then fabricated on a printed circuit board (PCB) with FR4-epoxy substrate material and tested using Vector Network Analyzer (VNA). Furthermore, the modified antennas are also tested in the high voltage laboratory to detect PD in needle–plane electrode. The experiment results show that both modified bowtie antennas can successfully detect the PD signal with correct phase patterns, and that the middle-sliced modified bowtie antenna is more sensitive than the rounded edge modified bowtie antenna.

A 20-180MHz frequency band electrically tunable antenna for radiation immunity testing

Electromagnetic compatibility (EMC) is an essential part in today’s society and there are more products around us that emit electromagnetic waves than ever before. To make sure that all these products function properly under all circumstances EMC testing is needed. One test that is conducted is radiated immunity testing. A susceptibility antenna is needed to perform immunity testing. This research work aims to show that a tuneable antenna could be used for immunity testing in the frequency band 20-180 MHz and in the future replace the current antenna, which is not tuneable, used at SAAB Support and Services EMC. A simulation program called EZNEC+ was used to simulate different antennas that were tested in the semianechoic chamber at SAAB. Two antenna types showed better efficiency and reached lower in frequency than SAAB’s current antenna. These antennas were a bowtie antenna and an x-shaped antenna, both extending in

A Compact Dual-band Octal Patch Loaded with Bow-tie Parasitic MIMO Antenna Design for 5G mm-Wave Wireless Communication

A Compact Dual-band Octal Patch Loaded with Bow-tie Parasitic MIMO Antenna Design for 5G mm-Wave Wireless Communication

Graphene Based Room-Temperature Terahertz Detector with Integrated Bow-Tie Antenna

Graphene Based Room-Temperature Terahertz Detector with Integrated Bow-Tie Antenna

Design and Optimization of a Bowtie Antenna for Ground Penetrating Radar (GPR) System

Design and Optimization of a Bowtie Antenna for Ground Penetrating Radar (GPR) System

A Compact Broadband Stepped Bow-Tie Antenna for Ambient RF Energy Harvesting

A Compact Broadband Stepped Bow-Tie Antenna for Ambient RF Energy Harvesting

Design of Compact Bow-Tie Slotted Antenna for Satellite Communication

A printed antenna using the slot-loading technique is adapted in the design to achieve multiband. A rectangular microstrip (printed) antenna with a Bow-Tie shape slot embedded on the radiating patch using a glass epoxy substrate with dimensions 3.34 x2.47 x 0.16 cms. The antenna is simulated using high-frequency structure simulator software and fabricated using a photolithography process. Experimental results are measured using a vector analyzer. the proposed antenna is resonating at three different frequencies 4.62 GHz, 8.14 GHz, and 12.41 GHz with a return loss of -20.00 dB, -25.09 dB, and -26.45 dB respectively. The antenna is resonating between 4.62 GHz to 12.41 GHz frequency which covers applications in the field of satellite (space to earth)5.441 and mobile communication 5.463.

A dual-band high gain complementary splitring resonator (CSRR) loaded hexagonal bowtie antenna with enhanced bandwidth for Vehicleto- Vehicle (V2V) communication applications

A highly reliable and efficient communication system is needed for a vehicle to navigate and drive to the destination without human control (known as an autonomous or self-driving vehicle). In this work, we consider various parameters for the antenna design, ensuring reliable communication amongst vehicles and infrastructure. Specifically, we consider the type of antenna, the method used, operating frequency, substrate type (with thickness and permittivity), size and shape, gain, and bandwidth. An optimal threshold value or range of these parameters is identified. Moreover, a complementary split-ring resonator (CSRR) metamaterial (MTM) based hexagonal bowtie antenna for a high gain V2V communication environment is presented. This antenna covers sub- 6 GHz fifth generation (5G) bands (3.15-3.95 GHz) and Wi-Fi band 2.4GHz. Printing was done on a low-cost FR4 substrate for the radiating patch. Antenna Bandwidth is enhanced using a partial ground plane. The radiating layer is based on hexagonal patches printed on the double side of the substrate, and the CSSR structure is etched from patches to enrich antenna gain and bandwidth. More importantly, the proposed CSRR employed antenna provides gain and bandwidth of 1.6dBi / 6 dBi and 100MHz/ 8000MHz at 2.4GHz /3.5GHz, respectively. A highly known software, CST microwave studio, simulates the proposed antenna. Simulated and measured results make this arrangement a potential candidate for 5G high gain V2V communication.

High-Tc Superconducting Josephson Junction Harmonic Mixers with Stub Tuners on Integrated Bowtie Antennas

Ordinary mixers can hardly meet the requirements in terahertz (THz) communications due to the low-power and expensive THz sources. Sensitive harmonic mixers have been widely studied to avoid this problem, owing to the fact that the higher the number of harmonics, the lower the local oscillator (LO) frequency, and the lower the cost. High-Tc superconducting (HTS) Josephson junction (JJ) mixers are performing candidates for THz receiver frontends because of the advantages of excellent sensitivity, wide bandwidth, high harmonic number and low LO power requirement. However, the normal-state resistance of HTS JJ is so low that traditional antennas are difficult to match it. In other words, it is quite a challenge to match the input impedance to a low input impedance for traditional antennas, especially for antennas fed by coplanar striplines (CPSs). In this work, based on the structure of bowtie, two types of stub tuners were integrated to decrease the impedance of the bowtie antenna so as to improve the coupling efficiency between the traditional bowtie antenna and the JJ. Furthermore, HTS YBa2Cu3O7-δ (YBCO) JJ harmonic mixers coupled with the proposed structures and fed by CPSs are fabricated and measured. The measurements show that the JJ mixer coupled with a pair of open-end stubs of the bowtie antenna achieves up to 88 harmonics, with a conversion efficiency of −69.6 dB. In contrast, the JJ mixer coupled with a pair of lumped-element stubs of the bowtie antenna only attains to 30 harmonics, with a conversion efficiency of −73.4 dB. Additional numerical simulations indicate that the coupling efficiency is enhanced when the complex impedance of the antenna is explicitly considered. Compared with other coupled traditional antennas, the JJ mixer with bowtie antenna has the largest harmonic number. This work paves the way for the future application of low-frequency and low-cost LO for THz communications.

Enhanced quantum efficiency and Purcell factor of incoherent light-emitting source modulators coupled with nanoantennas: DDA modeling and optimization

Gated tunable materials-based devices have proven efficient structures to dynamically control quantum emitters’ (QEs) photonic density of states. The active permittivity control enabled by these materials allows manipulating the coupling and dissipation of evanescent modes radiated by the QE, hence controlling the emission parameters. In this sense, we propose here the design and optimization of a plasmonic device coupled with nanoantennas capable of dynamically manipulating the QEs’ emission at visible wavelengths using a thin gated doped titanium nitrate layer. We explore the use of metallic cubic and bow-tie antennas and study their unique characteristics related to enhancing the QEs’ emission. For the nanoantenna geometrical parameters optimization, we propose a discrete-dipole-approximation (DDA) method to accurately calculate all the radiation parameters of a QE embedded in a layered medium coupled to a nanoantenna. This technique allows calculating the decay behavior of QEs arbitrarily distributed, which is only feasible with knowledge of the Purcell factor and quantum efficiency mapped for all possible positions, easily achieved with the proposed model. We show that by employing the proposed DDA, the time required for optimizing and building those maps to evaluate the device’s response is drastically reduced (98%) compared to conventional numerical techniques. Using the DDA to optimize the antenna allowed the device’s quantum efficiency to be enhanced from 1.8% (no nanoantenna) to 8% and 10.5% using the cubic and bow-tie nanoantenna, respectively. In addition, the nanoantenna helps decrease the QE lifetime by a factor of approximately 2, allowing faster modulation speeds. Finally, our modeling and findings can be used to pave the way for the design of new gated optical modulators coupled with nanoantennas for applications that require amplitude modulation.

Wideband Ferrite-Loaded Bow-Tie Antenna of Extremely Low-Profile

A large ground plane can severely degrade an antenna’s performance if its polarization is parallel to the ground and its profile is only a very small fraction of the operating wavelength. In this article, a wideband and very low-profile bow-tie dipole antenna is proposed to operate in the VHF/UHF band, which can be placed above a large ground plane. A step-by-step design with three main strategies: adding parasitic shorted walls, inserting parasitic triangle patches, and employing ferrite material, is introduced to make the antenna radiate in a wide band and maintain a very low profile. Another two methods using folded strips and modified interfingered structure are adopted to achieve the challenging goal of its realized gain greater than 2.0 dBi over a bandwidth of 218–650 MHz. The antenna’s profile is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.036~\lambda _{0}$ </tex-math></inline-formula> and its area is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.22\times 0.44\,\,\lambda _{0}$ </tex-math></inline-formula> , where <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 lowest frequency of 218 MHz. Experimental verification is carried out, and the measured results are in good agreement with the simulated ones.

Research and Application of Compact Air-Coupled Ground Penetrating Radar in Thin-Layer Asphalt Thickness Testing and Vibration Resistant Calibration Method

For high-precision continuous thickness measurement of thin-layer asphalt loose paving, the paper proposes a compact ground penetrating radar (GPR) solution with smaller volume than the conventional air-coupled antenna. It takes into account the minimum identifiable thickness of the GPR tailing characteristics of radar signals, the common thickness range of thin-layer asphalt, and the vibration of construction machinery. In general, the overlap between bottom reflection and surface reflection of thin-layer asphalt can be solved by subtracting the reflection of the asphalt surface from the calibration waveform file of a metal plate. However, because the operating environment of asphalt paving is not suitable to realize the frequent static calibration of metal plates, the paper designs a bow-tie antenna loaded with high loss absorbent material substrate, which significantly improves the signal tailing phenomenon and greatly reduces the size of the air-coupled antenna. At the same time, in view of dynamic change of paver vibration and the requirements of the construction site, less calibration is more advantageous. Based on the full-amplitude reflection method, a fitting formula for the dielectric constant of asphalt suitable for mechanical vibration is proposed in this paper, to further improve the engineering applicability of the detection system. Finally, static calibration asphalt thickness, dynamic measured dielectric constant asphalt thickness, and manual sampling thickness under three construction conditions are compared, and the capability of the compact air-coupled GPR detection system proposed in this paper is comprehensively verified.

Flexible Gas-Permeable and Resilient Bowtie Antenna for Tensile Strain and Temperature Sensing

As a wireless basic unit, flexible antennas hold a wide range of applications in wearable electronics, soft robotics, and Internet of Things (IoT). However, most of the current flexible antennas are encapsulated by silicone elastomers with poor gas permeability, which severely hinders the evaporation of skin moisture and sweat. In addition, conventional rigid metals as high-frequency conductors are limited by poor elasticity and susceptibility to oxidation for on-skin application. Here, we developed a highly permeable and stretch-resistant flexible bowtie antenna that can capture changes in tensile strain and temperature. A low-impedance flexible carbon nanotube-silver (CNT-Ag) substrate was fabricated as the conductor of the antenna. By optimizing the multibeam bowed geometry and wrapping it in porous thermoplastic polyurethane (TPU) fibers, the final five-beam antenna was obtained and was able to withstand a relatively large tensile stress of 25.2 MPa, yet achieve a high vapor transmission rate of 48.2 mg cm−2 h−1. The antenna obtained an ideal impedance match at 2.28 GHz with doughnut-like radiation and a high radiation efficiency of over 85%. Furthermore, the antenna was successfully used to capture the strain in the wrist epidermis during bending and to detect thermal changes in the beaker of hot water, respectively. Finally, demonstrations of the antenna, such as permeability, radiation to the human body, and integrality in connection with flexible circuits, were carefully developed to reveal its feasibility in the real world. We expect this work to pave the way for the future establishment of epidermally flexible antennas for soft electronics.

Study of metasurface coated bowtie antenna to decouple closely coupled arrays

This paper presents the numerical studies of the bowtie antenna with and without metasurface in cross-coupled arrays. The single bowtie antennas coated by the metasurface are designed at the neighboring frequency of 3 GHz. The cloaked frequency of the cloaked bowtie antennas is controlled by components that consist of metasurface such as the dielectric constant of the supporting material, slot width, spacing of the slot, and the height of the material. The cloaked bowtie antenna has characteristics such as the minimum reflection from the antenna at the designed frequency and, at the same time the radar cross section has a low value at the cloaked frequency. This characteristic has been intensively explored with closely cross-coupled antennas in array configurations as 1D lateral arrangement and 2D arrangement for the sequential and simultaneous modes. It is numerically confirmed that the characteristics of the cloaked coupled arrays are kept the same as those of a standalone array, which is shown to have robust characteristics to the mutual coupling between strongly coupled elements.

Hybrid OTA Chamber for Multidirectional Testing of Wireless Devices: Plane Wave Spectrum Generator Design and Experimental Demonstration

This article investigates practical implementation aspects of a novel hybrid chamber concept that has been recently introduced for over-the-air (OTA) testing of wireless devices. The chamber allows to synthesize a spectrum of plane waves (PWs) incident on a device under test (DUT) from a wide range of angles of arrival (AoAs) through exploiting multiple field scattering inside the overmoded waveguide (WG) chamber. An optimal design approach for the plane wave spectrum generator (PWSG) array inside the chamber is presented considering: 1) array antenna impedance matching for the desired test zone (TZ) quality and AoAs’ range; 2) an operational frequency bandwidth of the test environment and an instantaneous signal bandwidth; and 3) the impact of PWSG excitation errors. A robust linearly constrained minimum variance (LCMV) beamformer is formulated to realize the desired test environment over a wide frequency band, while accounting for the varying number of the WG propagating modes as excited by PWSG array. Numerical simulations and measurements with the first prototype of the hybrid chamber for FR1 frequency band (~3.5 GHz) are presented. This prototype includes a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${7\times 7}$ </tex-math></inline-formula> bowtie antenna element PWSG array, a 1.00 m <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times1.25$ </tex-math></inline-formula> m <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times1.75$ </tex-math></inline-formula> m metal WG chamber, an off-line optimal array beamforming setup, and a planar scanner for TZ characterization.

Low-Profile and Wideband Unidirectional Antenna With Ferrite Loading for UHF Applications

A low-profile and wideband unidirectional antenna with ferrite loading is presented for ultrahigh-frequency (UHF) applications. This design comprises a slotted bowtie antenna with parasitic elements placed 50 mm over a ground plane. A small amount of ferrite loaded on the center of the ground plane plays a crucial role in improving the performance of the low-profile antenna. The ferrite used here is a new type of magnetodielectric material with relatively high permeability and permittivity, as well as low magnetic and dielectric loss. The loaded ferrite introduces an additional phase change of the electromagnetic field reflected by the ground to improve the impedance matching, bandwidth, efficiency, and gain of the low-profile antenna. The evolution process and mechanism of the proposed antenna are elaborated. For validation, an optimized antenna prototype was fabricated and measured. The measured results are consistent well with their simulations, which shows the realized gain of 7.2–9 dBi over <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert \le -10$ </tex-math></inline-formula> dB impedance bandwidth of 38% (480–705 MHz). The overall profile of this antenna is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.08\lambda _{0}$ </tex-math></inline-formula> , where <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 lowest frequency of operation.