Wideband Dipole Research Articles

Adaptive adjustment method of segment linear frequency modulation excitation for wideband dipole logging

Abstract Wideband dipole signal is the basis for dipole dispersion correction and near-borehole imaging. Segment linear frequency modulation (SLFM) sound source signal is an effective method to broaden the dipole frequency band. In the actual logging process, the formation environment changes in real time, and the SLFM sound source with fixed parameters cannot compensate the bending wave excitation intensity curve at any time, which affects the quality of logging. This paper presents a method for adaptive adjustment of the SLFM sound source signal. Adaptive parameter adjustment can be made according to the change of downhole environment, so that the signal can be adapted to the changing downhole geological environment.

Application of Resonant Modal Theory to the Design of Dual-Band Wideband Dipole Antenna

Application of Resonant Modal Theory to the Design of Dual-Band Wideband Dipole Antenna

Study on the Conductivity Effect on the Characteristics of a Wideband Printed Dipole Antenna Implemented with Silver Nanoparticle Ink

This study examined a flexible composite wideband dipole antenna implemented with conductive silver nanoparticle ink having different conductivities. Two identical split ring resonators (SRRs) were designed to encompass each arm of a dipole element, and each dipole arm and its coupled SRR were printed on the top and bottom sides of a dielectric substrate. The overall dimensions of the compact antenna were 10 mm × 74.8 mm × 0.254 mm (0.053λo × 0.399λo × 0.0014λo at 1.6 GHz). The characteristics of the antenna with different conductivities were numerically investigated and experimentally confirmed. Our investigation aimed to ascertain the proposed antenna's response to different conductivity values and to determine the range of conductivity values that generates major changes in the antenna's performance characteristics in terms of impedance bandwidth, gain, and radiation efficiency. At conductivity values less than approximately 6.0 × 104 S/m, the number of generated resonances changed from three to two, and the antenna experienced a nearly 3-dB gain reduction when the conductivity approached 5.8 × 104 S/m.

Dual-Polarized Dipole Antenna with Wideband Stable Radiation Patterns Using Artificial Magnetic Conductor Reflector.

This paper presents a wideband dual-polarized dipole antenna structure operating at 1.7-3.8 GHz (76.4%). For a traditional 4G dipole antenna that covers the band 1.71-2.69 GHz, it is difficult to maintain the satisfactory impedance matching and normal stable radiation patterns within the 5G sub-6 GHz band 3.3-3.8 GHz, mainly due to the fixed antenna height no longer being a quarter-wavelength. To solve this, a connected-ring-shaped metasurface structure is proposed and deployed to operate as an artificial magnetic conductor (AMC). As a result, stable antenna radiation patterns are obtained within the whole band 1.7-3.8 GHz. For verification, this wideband dipole antenna using AMC is implemented and tested. The measured results show that the proposed antenna has an impedance bandwidth of 80.7% (1.7-4.0 GHz). It has an average measured in-band realized gain of 7.0±1.0 dBi and a stable 70±5 half power beam width (HPBW) within the 4G/5G-sub 6GHz bands 1.71-2.69 GHz and 3.3-3.8 GHz.

A Wideband Dipole Based on Odd and Even Mode Fusion

A Wideband Dipole Based on Odd and Even Mode Fusion

A Mode-Compressed Wideband Dipole Antenna Integrated With Solar Cell for Dual-Functional Operation

A Mode-Compressed Wideband Dipole Antenna Integrated With Solar Cell for Dual-Functional Operation

A Dual-Circularly Polarized Wideband Dipole Antenna With Stable Axial-Ratio and Half-Power Beamwidths

With wide impedance bandwidth (IBW), wide axial-ratio bandwidth (ARBW), stable AR beamwidth, and stable half-power beamwidth (HPBW), a dual-circularly-polarized (DCP) crossed-dipole antenna is proposed. Each dipole consisting of two patches is fed by a pair of parallel transmission line, leading to a wide IBW. To enhance the ARBW and AR beamwidth, a quadrature wideband coupler is used, and the overlapping bandwidth of IBW and ARBW is up to 100%. The quadrature coupler is integrated with two pairs of parallel transmission line, and are printed on two substrates, which are squeezed into the space between the radiators and reflector, resulting into a compact antenna structure. With a total height of 0.016 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> , a prototype is fabricated and measured, showing 1.5-VSWR IBW of larger than 104% for both Left-handed CP (LHCP) and Right-handed CP (RHCP), 3-dB ARBW of up to 100% both for LHCP and RHCP, and port-to-port (polarization) isolation of lager than 30 dB in 1.70 - 2.82 GHz, so the effective bandwidth (EBW) is about 50% (1.70 - 2.82 GHz). 3-dB AR beamwidth of 76° ± 5°, stable DCP characteristics with average gain of 7.2 dBi and HPBWs of 67° ± 4° are achieved.

Third- and Fifth-Order Mode Compression of a Dipole Antenna

This communication proposes a novel tri-mode wideband dipole antenna with mode compression. Tri-mode operation and wide bandwidth (BW) are obtained by compressing the third- and fifth-order modes simultaneously and combining them with the first-order mode. The third-order mode is compressed using an elliptical loop formed by loading two identical semi-elliptical stubs at the current-null points of the third-order mode. The overlap area and size of the loop play a critical role to compress/shift the mode. Two symmetrical pairs of L-shaped stubs loaded at the second current-null points of the fifth-order mode compress the fifth mode. The amount of compression depends on the stubs’ length. The stub width and position affect the impedance matching. The proposed antenna has an operational BW from 2.75 to 7.43 GHz that equals to 91.9% BW. The peak gain and electrical size are 3.8 dBi and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.32\lambda _{L}\times 0.14\lambda _{L}$ </tex-math></inline-formula> , respectively. The radiation pattern is omnidirectional over the entire impedance BW. A prototype was developed, and the experiments were performed to validate the design concept and computational results. The experimental results are well within the range of the simulation results.

Antenna-coupled microbolometer based on VO2's non-linear properties across the metal–insulator transition region

This paper presents an antenna-coupled non-linear vanadium dioxide (VO2) microbolometer operating in the non-linear metal–insulator transition (MIT) region with an ultra-high responsivity of 6.55 × 104 V/W. Sputtered VO2 films used in this device exhibit 104 times change in resistivity between the dielectric and conductive states. The VO2 microbolometer is coupled to a wideband dipole antenna operating at 31–55 GHz and a coplanar waveguide for probed measurement. To enhance the sensitivity, the sensor is suspended in air by micro-electro-mechanical systems process. The large thermal coefficient of resistance of VO2 is utilized by DC biasing the device in the MIT region. Measurements for the fabricated sensor were performed, and a high responsivity was demonstrated, owing to non-linear conductivity change in the transition region. The measured sensitivity is &amp;gt;102 times higher than the state-of-the-art sensors. In addition, the concept of utilizing the proposed VO2 sensor in a mmWave imager was demonstrated by the radiation pattern measurement of a 4 × 4 (16 elements) antenna-coupled VO2 sensor array. The results presented in this work reveal the initial step to employ VO2's MIT for a hyper-sensitive sensor in future mmWave sensing and imaging applications.

A slotline‐fed wideband dipole with filtering gain response

A slotline-fed wideband filtering dipole with tuneable radiation nulls is presented in this paper. The proposed wideband filtering dipole is fed by the microstrip–slotline cross-junction. On account of the open-circuit fed-transmission-line structure (OFTL) loaded on the extending line of microstrip–slotline cross-junction, the wideband dipole generates two radiation nulls distributed at the lower and upper fringe of the operating band. The OFTL structure not only bring the filtering response but also can move the two radiation nulls simultaneously and keep the in-band radiation performance unchanged. To validate the proposed approach, the wideband filtering dipole is fabricated, and the measured results are consistent with simulated results. The impedance bandwidth of the proposed antenna is 22.4% (3.49–4.37 GHz), and the gain within passband is about 2.7 dBi. Moreover, the out-of-band radiation suppression levels are more than 20 and 10 dB within lower stopband (2.21–2.88 GHz) and upper stopband (4.92–5.78 GHz), respectively.

Compact Wideband and Variable Impedance Transformation Ratio Balun for Folded Dipole

Aiming at dipoles with different impedances, a wideband balun with adjustable impedance for the balanced port is proposed in this communication. The balun is directly connected to the dipole to form an antenna element, so it also needs to meet: no connection line is required; the overall size is less than a quarter of the wavelength. The proposed balun realizes balanced–unbalanced conversion through aperture coupling, and dual slot ensures its wide-band characteristics. Due to the high-impedance characteristics of the folded dipole (FD), the balun has achieved impedance conversion ratios of 6:1, 8:1, 10:1, and 12:1, and the corresponding bandwidths are 82.1%, 67.1%, 53.7%, and 44.4%, respectively. Finally, three types of wideband dipoles with different characteristic impedances are fabricated to verify the versatility of the balun.

Stretchable 3D Wideband Dipole Antennas from Mechanical Assembly for On-Body Communication.

The development of wearable/stretchable electronics could largely benefit from advanced stretchable antennas with excellent on-body performance upon mechanical deformations. Despite recent developments of stretchable antennas based on intrinsically stretchable conductors, they are often affected by lossy human tissues and exhibit resonant frequency shifts upon stretching, preventing their applications in on-body wireless communication and powering. This work reports a three-dimensional (3D) stretchable wideband dipole antenna from mechanical assembly to simultaneously reduce the frequency detuning and enhance on-body performance. The large bandwidth is achieved by coupling two resonances from two pairs of radiation arms, which is well-maintained even when the antenna is directly placed on human bodies or stretched over 25%. Such an excellent on-body performance allows the antenna to robustly transmit the wireless data and energy. The design of the 3D stretchable wideband dipole antenna with significantly enhanced on-body wireless communication performance was validated by an experimental demonstration that features a small difference in the wirelessly received power between the on-body and off-body use. The combination of the mechanically assembled 3D geometries and the coupled mechanical-electromagnetic properties can open up new opportunities in deformable 3D antennas and other microwave devices with excellent on-body performance and tunable properties.

A Dual Slant-Polarized Cylindrical Array of Tightly Coupled Dipole Antennas

This study proposes a design of a low-profile ultra wide-band cylindrical antenna array with plus/minus 45-degree dual polarization. The proposed compact cylindrical antenna array produces an omnidirectional radiation pattern in the azimuth plane to cover all directions. It consists of <inline-formula> <tex-math notation="LaTeX">$20\times 4$ </tex-math></inline-formula> dual-polarized elements within a diameter of 131 mm and a height of 116 mm. The array elements are tightly coupled slant-polarized wideband dipole antennas, and hence, rotational symmetry of radiation patterns in the horizontal plane is achieved for the two orthogonal polarizations. Furthermore, a metasurface structure has been designed and placed over the interconnected array elements to achieve ultrawideband capabilities. The proposed array provides less than &#x2212;10 dB reflection coefficient over a frequency band between 1.7 GHz and 5.9 GHz. The cross-polarization discrimination (XPD) is 15 dB at boresight in the azimuth plane. The electromagnetic characteristics of the cylindrical array and its corresponding planar array before bending have been evaluated and compared via simulations, and verified by measurements. The compact size, lightweight, and printable design of the proposed antenna array enable low-cost manufacturing and ease of installation. The proposed array design overcomes many challenges encountered in wide-band MIMO systems by covering the entire sub-6 GHz band while providing wide 360-degree coverage in the azimuth plane, hence, supporting multibeam applications.

A Compact Wideband Dipole Antenna With Wide Beamwidth

A wideband dipole antenna with wide beamwidth fed by a coaxial balun is presented. The proposed antenna contains a parasitic patch, a U-shaped reflector, and a pair of L-shaped metal arms. The parasitic patch located above the L-shaped metal arms (as an electric dipole) functions as a director. The combination of the U-shaped reflector and the pair of L-shaped metal arms acts as a magnetic dipole. The wideband impedance bandwidth and wide beamwidth are achieved by using the magnetoelectric dipole. The characteristic mode method is used to facilitate the analysis of the antenna. The measured results show that an impedance bandwidth of 0.78-3.05 GHz (118.5%) for VSWR ≤ 2 is obtained. The beamwidth is between 110° and 179° in the band of 0.78-3.05 GHz (118.5%) in the H-plane, and between 83° and 146° in the band of 0.78-2.47 GHz (104%) in the E-plane. The overall size of the antenna is 0.177λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.239λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.104λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> is the free-space wavelength at the starting frequency).

Single-Chip Two Antennas for MM-Wave Self-Powering and Implantable Biomedical Devices

Implantable biomedical applications arise the need for multi-band sensors with a wideband frequency channel for RF energy harvesting operation. Using a separate antenna for energy harvesting can simplify device circuit complexity and reduces operation frequency bands interference. This paper demonstrates the design of single chip with two separate integrated antennas for implantable biomedical applications. The two antennas have different structures with orthogonal polarization to achieve low mutual coupling and negligible interaction between them. The first antenna is a multi-band meander line (MBML) designed for multiple channels data communication, with quad operating bands in the MM-wave range from 22-64 GHz with area 1150 × 200μm2. The second antenna is a wideband dipole antenna (WBDA) for RF energy harvesting, operates in the frequency range extend from 28 GHz to 36 GHz with area 1300×250μm2. The proposed antennas are designed by using high frequency structure simulator (HFSS) and fabricated by using UMC180nm CMOS technology with total area 0.55 mm2. The MBML frequency bands operating bandwidths can reach 2 GHz at impedance bandwidth ≤ -10 dB. While, the WBDA antenna has gain -2 dB over the operating band extend from 28 GHz up to 36 GHz. The antenna performance is simulated separately and using the human-body phantom model that describes layers of fats inside body, and shows their compatibility for in body operation. Die measurements is performed using on wafer-probing RF PICOBROBES and shows the matching between simulation and measurement values.

A Compact Nonsymmetric Wideband Dipole Antenna for Borehole Radar Application

Borehole radar (BHR) is one of the most important types of ground-penetrating radar and has very strict requirements for antenna. Considering the detection resolution and the limited borehole size, the BHR antenna should be both wideband and compact. In this article, a compact nonsymmetric wideband dipole (NSWD) antenna is proposed. One arm of the NSWD antenna consists of several patches with different lengths, and the other one is a hollow metal tube. The combination of patches which are resistively loaded at the ends is used for increasing antenna bandwidth and frequency reconstruction. In addition, a three-section binomial matching transformer is designed for impedances match between antenna ( 120 Ω) and coaxial cable ( 50 Ω). Matching transformer and other radar system devices are housed in the hollow metal tube, which makes the BHR system much compact. The central frequency of the antenna is set to 86 MHz for long-range detection. The proposed antenna is fabricated and measured. The measurement results show that the proposed antenna has the advantages of wide bandwidth (~41.8% from 68 to 104 MHz) and high radiation efficiency (~65%). Finally, the antenna (including electronics) is assembled into a polyvinyl chloride pipe to form a BHR prototype, and we used it to conduct a field test in a water-filled borehole. The experimental results show that the NSWD antenna can work well with the BHR system inside borehole.

Stretchable wideband dipole antennas and rectennas for RF energy harvesting

The ultimate application of bio-integrated, stretchable electronics hinges on the indispensable modules of stretchable wireless data transmission and power supplies. While radiofrequency (RF) antennas and rectennas could enable wireless communication and RF energy harvesting in the far-field, their performance deteriorates because of the frequency detuning from mechanical deformations. Here, stretchable wideband antennas and rectennas are introduced to robustly operate and combine received RF power over their wideband upon mechanical deformations. Devices with stretchable wideband antennas and rectennas create application opportunities such as self-powered systems, remote monitoring of the environment, and clean energy. A comprehensive set of manufacturing schemes, device components, and theoretical design tools for the stretchable wideband antennas and rectennas is reported. A stretchable wideband rectenna integrated with various functional sensing modules and its demonstration with enhanced effective efficiency over the state-of-the-art by 10–100 times illustrates a system-level example of this technology.

Ink-printed flexible wideband dipole array antenna for 5G applications

This article presents a novel flexible wideband ink-printed dipole array antenna for emerging medical sensing and human body wearable electronics applications. The antenna operates from 23 GHz to 30 GHz, including 24.5 GHz and 28 GHz for 5G application. The antenna consists of simple layered screen printed structure, which is suitable for rapid prototyping with printing technology. Both simulation and measurement results are presented, which shows a percentage bandwidth of 26.4% and a maximum forward gain of 4.2 dBi. Further investigations are conducted to analyze the effects of imperfect fabrication process on the antenna performance.

Design of wide band compact bend triangular resonator artificial magnetic conductor and its application for antenna gain enhancement

SummaryIn this paper, a compact bend triangular resonator (CBTR) structure is proposed as artificial magnetic conductor (AMC) to enhance antenna gain for wide frequency bandwidth. This paper presents the metamaterial properties of the CBTR structure like absorbance and reflection phase. The CBTR unit cell gives in‐phase reflection (0° ± 90°) for 55.2% bandwidth. The CBTR unit‐cell reflection phase analysis is presented for the different height of normal incident wave. The CBTR AMC performance is validated using a wideband dipole antenna. For −6‐dB impedance bandwidth, the standalone dipole antenna covers ultrawide frequency range 3.1–12 GHz and for −10‐dB impedance bandwidth, antenna has dual band frequency response 3.4–4.4 GHz and 8.3–11 GHz. The antenna shows good impedance matching and radiation characteristics for frequency range, where the unit‐cell reflection phase is 135° to 45° for frequency range 2.5–6.5 GHz (bandwidth of 88.8%). The broadside directivity of 7 dBi is achieved for the dipole antenna with CBTR AMC in the frequency range of 2.5–6.5 GHz and broadside gain of &gt;5 dBi in the frequency range of 3.2–6.7 GHz (bandwidth of 70.7%). The antenna efficiency of 60% (minimum) is achieved for the frequency range of 3.68.0 GHz (75.8%). The proposed CBTR design is orthogonally symmetric and is useful for dual‐polarized wideband frequency applications like wireless local area network (WLAN) (2.4–2.5 and 5.15–5.85 GHz) and new radio (NR) 5G sub‐6‐GHz (3.3–5.0 GHz).

Mode Compression Method for Wideband Dipole Antenna by Dual-Point Capacitive Loadings

In this communication, a dual-mode compression method is proposed for wideband applications of thin dipole antennas. In this method, only two points along the thin dipole antenna are properly found and loaded by two capacitors, lumped or distributed. At these two loading points, there are current nulls of the third mode of the dipole. With two capacitive loadings, an obvious upshifting of the first mode's resonant frequency is observed but with little effects on the third mode. By compressing the first and third modes, an enhancement of the antenna bandwidth is achieved. In addition, a parallel line is used as a transformer for impedance matching. A prototype of the design has been fabricated and tested. The measured results agree well with the simulated ones. In the thin structure of 1.01 × 0.09 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free space wavelength at the center frequency), a wide bandwidth from 1.88 to 3.18 GHz (51.4%) is achieved, performing an omnidirectional radiation pattern with gain of 2.0-4.0 dBi in azimuthal plane.