Low-profile Ultra Wideband Research Articles

Design and Validation of Loop-Based Ultraminiature Low-Profile Ultrawideband Capsule Antenna Inside Wistar Rat

Design and Validation of Loop-Based Ultraminiature Low-Profile Ultrawideband Capsule Antenna Inside Wistar Rat

Low-Profile Ultra-Wideband Dual-Polarized Omnidirectional Antenna for Indoor Base Station

A low-profile ultra-wideband omnidirectional antenna with dual polarizations for indoor mobile communication is presented. The horizontally polarized (HP) omnidirectional element is introduced by using twelve I-shaped slot antennas, which are arranged in a circle-shaped array and excited by a 1-to-12 power divider. The vertically polarized (VP) omnidirectional performance is introduced by using a dual-M-shaped monopole with a small ground plane. To enhance the impedance matching within an ultra-wide bandwidth, a top metal disk with four chunks, a bottom metal loop and a ring slot embedded in the ground plane are employed for the design of the VP element. After replacing the metal disk of the VP element with the designed HP element, the omnidirectional antenna with dual polarizations is then simply achieved. By utilizing this new method, an ultra-wideband dual-polarized omnidirectional antenna for indoor mobile communications is designed, manufactured and measured. It has an ultra-wide bandwidth of 117% (1.44-5.5 GHz), a high isolation of 30 dB, and a low profile of 0.16λ <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> denotes the wavelength at the lowest frequency of the operating band). Good omnidirectional radiation performance with gain variation < 2.6 dBi is obtained for both HP and VP ports over the ultra-wide operating band.

A Low-Profile Ultra-Wideband and Wide-Scanning Phased Array for UHF Applications

This article presents a novel low-profile ultra-wideband and wide-scanning array antenna using the transversely connected folded tightly coupled dipoles array (TCF-TCDA). The tightly coupled folded dipole arms are used to extend the operational frequency band with a simple feed structure. The capacitively-loaded metallic walls are adopted to move the problematic common-mode resonance out of the desired band and mitigate the bandwidth-limiting loop mode at the lower frequency, as well as reducing the weight and cost. A meta-surface-based wide angle impedance matching (MS-WAIM) layer is used to improve the beam scanning ability and lower the antenna profile, which consists of the star-shaped patches loaded on the dipole element. To demonstrate the wideband and wide scanning-range capability, a prototype is designed with an 8:1 bandwidth (0.41–3.3 GHz) at broadside, a scanning range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm \mathrm{75}^{\circ }$ </tex-math></inline-formula> from 0.5 to 3.25 GHz (6.5:1 bandwidth) in the E- and D-planes and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm \mathrm{50}^{\circ }$ </tex-math></inline-formula> from 0.6 to 3.3 GHz (5.5:1 bandwidth) in the H-plane for active VSWR < 3.6. The proposed antenna has a very low profile, which 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">$0.07\lambda _{\mathrm {low}}$ </tex-math></inline-formula> at the lowest operating frequency. A 16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 16 array prototype is fabricated and measured. Experimental results show that the design and measurement results have good agreement. The proposed antenna has an ultra-wide bandwidth, a wide scanning range, a very compact size and a low cost, which is a good candidate for modern wireless system.

A Low Profile Ultra-Wideband Antenna Design with Reconfigurable Notch-Bands for Wideband and Narrowband Applications

A Low Profile Ultra-Wideband Antenna Design with Reconfigurable Notch-Bands for Wideband and Narrowband Applications

Low-profile UWB antenna with unidirectional radiation pattern analyzed with the theory of characteristic modes

This paper presents a low-profile Ultra Wide Band (UWB) antenna with polarization diversity for new 5G base stations. The antenna consists of a metallic ring capacitively fed with four circular monopoles and reinforced with a cylindrical cavity to generate a unidirectional radiation pattern. The Theory of Characteristic Modes is used to analyze and explain the behaviour of the proposed antenna excited with differential feeding configurations. A prototype of the optimized design has been manufactured and measured, yielding good impedance matching (S11<-10 dB) from 3 GHz to 6 GHz with maximum directivity of 10.51 dBi. Measured and simulated results are in good agreement.

Design and analysis of low profile and low SAR full-textile UWB wearable antenna with metamaterial for WBAN applications

In this paper, a low-profile wearable antenna with metamaterial (MM) for wireless body area network (WBAN) applications is presented. The designed antenna with MM operates in the ultra-wideband (UWB) between 4.55 and 13 GHz and it has a thickness of 4.68 mm. To the best of our knowledge, it is the lowest thickness reported in the literature for UWB antennas with MM. The proposed is designed and manufactured using fully flexible textiles. The designed antenna was simulated in free space and on the human body model. Simulation results show that gain, directionality, and front-to-back ratio of the antenna increase considerably with the placement of the MM. Also, in simulations, it is found that the specific absorption rate (SAR) values for the designed antenna reduce by 98.3% when MM is used. These SAR values calculated for the designed antenna with MM are well below the limits defined in European standards. The designed antenna and metamaterials were manufactured, too, and scattering parameters were measured. Measurement results are in good agreement with the results found in the simulations. It shows that the proposed antenna is very suitable for use in WBAN applications due to its low thickness, having low SAR, and UWB operation.

Ultrawideband Textile Antenna for Wearable Microwave Medical Imaging Applications

This article presents the design of a novel low-profile ultrawideband textile antenna for wearable microwave medical imaging systems. The proposed antenna is based on a monopole structure, where two triangles and a few parallel slots are cut at the bottom corners and top edge of the radiation patch, respectively, to achieve an optimized ultrawide bandwidth and a reduced size of the antenna. Polyester fabrics and conductive copper taffeta, which are universally available on the market, are selected to construct the antenna. Thus, the fabricated prototypes well suit the needs of wearable applications, where flexible components are required to conform to the curved human bodies. The measured results show that the antenna prototype can realize a bandwidth of 109% from 1.198 to 4.055 GHz, with a realized gain of 2.9 dBi. Furthermore, the on-phantom measurements show that there is limited effect on the operating bandwidth and realized gain of the antenna when it is working in the proximity to human bodies. The antenna is used to monitor the recovery process of a bone fracture that is emulated by a body-mimicking phantom with a size-varying blood strip. The time-domain reflection coefficient of the antenna varies significantly with the size of the fracture introduced, which demonstrates the applicability of the antenna for such use scenarios in microwave medical imaging.

Stub loaded, low profile UWB antenna with independently controllable notch‐bands

AbstractThe design and realization of a compact coplanar waveguide (CPW) fed ultrawideband (UWB) antenna having dual‐notched bands is presented in this article. The antenna possesses on demand notch bands at 4 to 5.78 GHz and 6.83 to 8.22 GHz. The presented design consists of a single iterated octagonal patch antenna designed on cheap FR4 substrate. The stub is utilized to achieve a wide impedance matching of 7.33 GHz (3.2‐10.5 GHz), while the notch‐bands are realized using split ring circular slots. These notch‐bands are controlled independently without affecting the overall performance of the antenna. Simulated and measured results showed that the antenna offers excellent performance with an overall size of 20 × 23 mm2, high efficiency of more than 90%, and a nearly omnidirectional maximum gain of 4.8 dBi. The performance of the proposed antenna is better than the antennas presented in the literature in term of size, stable gain, and independently controllable notch bands. Besides these advantages, the compact size allows the antenna to integrate into small devices easily and help manufacturers to produce a massive number of antennas comfortably.

A half cut design of low profile UWB planar antenna for DCS/PCS/WLAN applications

A miniaturized half cut coalesced kite shaped printed antenna is presented for the ultrawide band (UWB) characteristics. The proposed design bears a compact and small physical dimension of 25 (L) × 9 (W) × 1.6 (h) mm3. This structure produces higher impedance bandwidth as compared to the corresponding full structure of the antenna design. The variation of ground plane dimension is studied to get the optimized results of the antenna. The measured impedance bandwidth (return loss <10 dB) of the proposed antenna is found to be 16.12 GHz in the frequency range 1.02 to 17.14 GHz. The average measured gain for this design is 3.12 dBi for the entire band of operation. The far field radiation patterns are also presented at 1.18, 3.1, 6.85, and 10.6 GHz. The antenna performances are first analyzed by the CST Microwave Studio, the simulation software based on finite integration technology (FIT) and then the optimized structure is fabricated for the measurements. The proposed design structure reveals the recent state of art by using the half cut technique which not only miniaturizes the size but also covers the whole UWB range to be used for many wireless systems.

Low-Profile Low-Cost Ultra-Wideband Circularly Polarized Slot Antennas

Aiming for ultra-wideband (UWB) indoor wireless access, three low-profile UWB circularly polarized slot antennas are proposed in this paper, all of which are made by a pair of curved tapered slots. The slots are miniaturized to allow a short direct microstrip feeding. The first antenna is a bidirectional antenna with a measured -10 dB impedance bandwidth of 110% (2.94 - 10.06 GHz), and a 3 dB axial ratio (AR) bandwidth of 89% (3.19 - 8.26 GHz). Its measured peak gain is 7.5 dBic and its size is 0.80 λ max × 0.80 λ max × 0.5 mm (λ max is the free-space wavelength at the lowest frequency, 3.19 GHz). Its performance is similar to that of a traditional spiral antenna, but it has a much simpler structure with a more complete ground plane, making it possible to integrate with other components (e.g. filter and amplifier) on the antenna body to reduce the overall size of the system. The second antenna is a directional antenna with a simple solid metal reflector placed 21 mm away from the radiator. This configuration increases the peak gain to 8.6 dBic, but reduces the impedance bandwidth to 52% only. The third one is a directional antenna with a meshed reflector. It has a maximum gain of 9.6 dBic, which is higher than that of the second antenna, while its -10 dB impedance bandwidth is 99% (3.37 - 9.94 GHz) and its 3 dB AR bandwidth is 84% (3.70 - 9.07 GHz), which is similar to that of the first one. Also distance between the radiator and the reflector (antenna's height) is reduced to 9 mm only (0.111 λ max ). The proposed antennas demonstrate high efficiency, simple and low profile structures, wide impedance and AR bandwidth, making them excellent candidates for in-door base station and UWB positioning systems.

Design of a Multimode UWB Antenna Using Characteristic Mode Analysis

In this communication, a low-profile ultrawide band (UWB) antenna is designed, fabricated, and measured for TV white space devices (TVWSDs). Starting from a simple annular ring, the proposed design procedure is guided by the characteristic mode analysis. First, a closed-form estimation to the resonant frequencies of the first two characteristic modes for the annular ring structure is provided. Then, the annular ring is modified to introduce more characteristic modes resonating within the interested spectrum. To excite these modes and to achieve a wideband antenna covering the whole ultrahigh frequency (UHF) TV spectrum, the feeding structure is also carefully designed and refined. Finally, a prototype is fabricated and measured to verify its UWB performance, and radiation patterns at different frequencies are presented to prove the switching of dominating resonating modes. The analyses and performance evaluation show that the proposed antenna is a strong contender to be used for TVWSDs. Furthermore, thanks to the simplicity of tuning and controlling modal resonant frequencies, this procedure can be flexibly applied to various antenna designs.

A Compressed Low-profile Ultra Wideband Antenna for Biomedical Applications

This paper introduces a smaller planar ultrawideband (UWB) microstrip reception apparatus for microwave medicinal applications. The proposed reception apparatus has a position of safety structure, comprising of an altered transmitting patch with stair steps and open openings, microstrip encourage line, and T-like shape spaces at the ground plane. The enhanced recieving wire is fit for being worked in recurrence scope of 3.06–11.4 GHz band having great omnidirectional radiation example and high pick up, which fulfills the necessities of UWB (3.1–10.6 GHz) applications. The radio wire framework has a reduced size of 18×30×0.8mm3. These elements make the proposed UWB reception apparatus a decent contender for microwave therapeutic imaging applications.

A Low Profile UWB Antenna for WBAN Applications

In this paper, we propose a low-profile ultra-wideband (UWB) antenna for wireless body area networks. The proposed antenna is low-weight and easy to produce by printed circuit board manufacturing. Optimized shape of the radiation patch and shorted top-loading patches are introduced to broaden the bandwidth and reduce the profile of the antenna. The height of the antenna is $0.05\lambda _{0}$ , where $\lambda _{0}$ is the free-space wavelength at the lowest operating frequency. The simulated and measured results show that an enhanced impedance bandwidth of about 162% in the range of 2.5 to 24 GHz (S11 < −10 dB) is achieved. Besides, the influence of the human body to the proposed antenna is minimal. The time-domain behavior of the low-profile UWB antenna is tested, and the results show a satisfactory performance in transmitting and receiving pulse signals.

Measurement Analysis of Ultra-Wideband Monopole Antenna With Defected Ground Structure

This article describes how a compact, low profile Ultra-wideband (UWB) monopole antenna with a defected ground structure is designed and demonstrated experimentally. The design and experimentation activities have been carried out with the help of a CST Microwave studio tool. The UWB characteristics of the proposed antenna are achieved with a modification of the ground structure of the referenced antenna with novel L shaped defected ground structure (DGS). Both antennas are fabricated on the same substrate with the dimensions of 28.3 x 24 mm2. The comparative analysis of the results for both antennas clearly indicate that the proposed UWB monopole antenna enhanced the impedance bandwidth from 3.7 GHz – 14.9 GHz without DGS and to 3.4 GHz – 20 GHz with DGS. The enhanced bandwidth, constant group delay and good radiation characteristics of the proposed antenna have identified it as a good candidate for portable UWB applications.

A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection.

A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9–13.7 GHz) with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1–5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications.

Paper] Low Profile UWB Frequency Selective Surface based Antenna

In this paper, we present the design of a new ultra-wideband (UWB) frequency selective surface (FSS) based antenna, by using a wide stop-band FSS as a backing reflector for an UWB monopole antenna. A new single layer FSS, with UWB stop-band response and a reflection phase varies linearly with frequency, is firstly designed and thereafter, it is integrated with an UWB electric monopole. The studies of the behavior of the proposed antenna reveal that a unidirectional radiation with a quasi-constant gain of an average of 9dBi and a compact profile of λ/10 are achieved. The features of the proposed UWB FSS and its based antenna make them good candidates for integration with low profile broadband printed circuits and UWB applications.

자기상보 원리를 이용한 UAV 탑재용 초광대역 반파장 루프 안테나

In this paper, we present a low-profile ultra-wide band half-wavelength loop antenna for UAV (Unmanned Aerial Vehicle) applications. The proposed antenna has an ultra-wide band using self-complementary principle. Also, the ground was located between radiators for reducing height of the antenna using image theory. Dimensions of proposed antenna have ( is the free-space wavelength at lowest frequency). Measured -10 dB bandwidth was ultra-wide band as more than 50 : 1(over 0.3 GHz ~15 GHz). The radiation patterns of the antenna was omnidirectional like monopole antennas. Moreover, we tried the antenna mounted on under a fuselage of a scaled UAV. As a result, the proposed antenna on the UAV maintained ultra-wide band and omnidirectional radiation patterns at all frequencies.

Axial ratio reduced ultra wideband slot spiral on hybrid impedance surfaces

This paper presents a low-profile ultra wideband slot spiral antenna backed by a hybrid impedance surface. A unique aspect of the spiral is its hybrid impedance surface cavity leading to reduced axial ratio over a wide bandwidth. This is an improvement over conventional cavity-backed wideband spirals. Measurements demonstrated that the slot spiral on the proposed hybrid impedance surface achieved a 10:1 bandwidth from 0.6 to 6 GHz with an axial ratio of <4 dB. The cavity depth is only 13 mm, corresponding to 0.03λ600 MHz at its lowest operational frequency. As such, this slot spiral is attractive in enabling low-profile ultra wideband antenna with excellent RF performance for conformal and wearable applications.

Low Profile UWB Log‐Periodic Dipole Antenna for Wireless Communication with Notched Band

ABSTRACTA low profile Log‐Periodic dipole microstrip antenna is proposed for ultrawideband (UWB) applications. Logarithmically scaled dipoles with defected ground plane are fabricated on both of the sides of the dielectric substrate. The triangular taper transition is used for providing better matching. The proposed antenna shows an impedance bandwidth of 3.3–20.7 GHz, which covers the entire C, X, and Ku bands and partially S and K bands. The antenna shows stable radiation characteristics with a good front‐to‐back ratio for entire operating band. Further, a U‐shaped slot is integrated with the UWB antenna to provide a rejection function at narrowband wireless communication system such as IEEE 802.11a in USA (5.150–5.350 GHz and 5.725–5.825 GHz). The notched band is created at 5.8 GHz. The measured results reveal that the proposed antenna offers a very wide bandwidth with notched band at 5.8 GHZ. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2901–2906, 2013

Superstrate-Enhanced Ultrawideband Tightly Coupled Array With Resistive FSS

An efficient low-profile ultrawideband tightly coupled array employing a resistive frequency selective surface (FSS) and a superstrate is introduced. The FSS suppresses destructive ground plane interference, resulting in an increase in the array bandwidth by a factor greater than two. A superstrate is used to alleviate losses due to the resistive FSS. It is shown that a properly designed superstrate reduces losses by about 2.5 dB. The proposed array, which employs tightly coupled bowtie elements, achieves very low profile <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$(0.055\lambda_{\rm low})$</tex> </formula> , 21:1 bandwidth, and radiation efficiency greater than 73% across the band. This paper presents the analysis and design of the array, particularly the FSS and superstrate. To validate the design, measurements of a prototype array are presented as well.