Low-profile Ultra-wideband Antenna Research Articles

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.

A Low-Profile Ultrawideband Antenna Based on Flexible Graphite Films for On-Body Wearable Applications

This paper presents a low-profile ultrawideband antenna for on-body wearable applications. The proposed antenna is based on highly conductive flexible graphite films (FGF) and polyimide (PI) substrate, which exhibits good benefits such as flexibility, light weight and corrosion resistance compared with traditional materials. By introducing flaring ground and an arrow-shaped slot, better impedance matching is achieved. The wearable antenna achieves a bandwidth of 122% from 0.34 GHz to 1.4 GHz, with a reflection coefficient of less than −10 dB, while exhibiting an omnidirectional pattern in the horizontal plane. To validate the proposed design, the wearable antenna with a profile of ~0.1 mm was fabricated and measured. The measured results are in good agreement with simulated ones, which indicates a suitable candidate for on-body wearable devices.

A low profile dual-polarized tightly coupled dipole array of C-X-band.

Modern low-profile ultra-wideband antenna arrays are tightly coupled dipole array (TCDA). The paper presents a model of a low-profile dual-polarized of planar-type TCDA for operation in the 4÷12 GHz band with scanning in the sector of angles ±30° in two principal planes. In contradistinction to the well-known TCDAs, the proposed array is distinguished by its simplicity of design, the absence of balancing transformers, the extended period of 12x12mm, and the small height of 5.63mm (including the thickness of the upper homogeneous non-perforated matching layers of 1.67mm and the substrate layers of 3.968mm. The selected array period allows taking into account the special design requirements of the feed network for the array elements. The broadband of the TCDA (at VSWR&lt;3.6) is achieved using the upper matching layers. These layers also serve as the radome for the array.

Ultrawideband Circularly Polarized Antenna With Shared Semicircular Patches

A low-profile ultrawideband antenna of circular polarization (CP) is proposed in this communication. This antenna consists of two layers of Rogers RT/Duroid 5880 PCB board of 0.79 mm thickness. The size of the top PCB is 54.6 mm ×54.6 mm, and four pairs of semicircular patches are printed on both its top and bottom sides. This top PCB is placed 10.5 mm above the bottom PCB, which is 95 mm ×95 mm in size. On the top side of the bottom PCB is a 1-to-4 microstrip feeding network with 90° phase difference between the adjacent ports, while the ground plane is on its bottom side. The top PCB is supported by four small trapezoid-shaped PCB boards at the center of its four edges, respectively. A slot line is printed on each trapezoidal PCB to feed the patches. Both the simulation and measurement results show that this low-profile antenna has a very wide 10 dB return loss bandwidth from 2.9 to 9 GHz. Meanwhile, lower than 3 dB axial ratio can be achieved from 3 to 7.8 GHz and its right-hand circular polarized (RHCP) gain is higher than 8 dBic. The good performance of this antenna can justify that it is a promising candidate for indoor positioning applications that require CP.

A Conformal Band-Notched Ultrawideband Antenna With Monopole-Like Radiation Characteristics

A conformal, planar, and low-profile ultrawideband antenna with monopole-like radiation and band-notched characteristics is presented. A circular patch shorted to the ground is combined with two rectangular slots and two concentric rings, to achieve an ultrawide bandwidth from 3.8 to 8.3 GHz with a single rejection band from 5 to 6 GHz. The monopole-like radiation features, generated by combining TM $_{01}$ and TM $_{02}$ operating modes of a circular patch antenna, are maintained over the entire operating bandwidth. The antenna has only 0.046 $\lambda _{o}$ height at 3.8 GHz and is realized using polydimethylsiloxane conductive fabric composite technology making it highly flexible and physically robust. This was validated through severe bending tests with various curvatures.

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 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.

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, High-Gain, and Full-Band SubArray of Cavity-Backed Slot Antenna

A four-element array of cavity-backed slot antennas with high-gain and low cross-polarization is presented. The subarray is fed by a single microstrip line coupled to the low-profile cavity and provides the entire X-band bandwidth. This subarray is envisioned as the building block (tile) for the construction of scalable low-profile ultrawideband antenna arrays. The slot array is composed of a thin rectangular cavity of dimensions $1.2\lambda _{L}\times 1.2\lambda _{L}\times 0.15 \lambda _{L}$ ( $\lambda _{L}$ is the free space wavelength at the lowest frequency of operation) on which four slots are cut out for electromagnetic radiation. It is demonstrated that by inserting metallic septa with appropriate locations and sizes inside the cavity, multiple resonances with desired field distribution can be excited resulting in a wideband slot antenna with consistent radiation characteristics over 60% fractional bandwidth. Also, a compact end-launch microstrip to reduced-height waveguide transition is presented to feed the antenna. Silver 3-D printing is used to fabricate the cavity and the standard printed circuit board technology is used to fabricate the feed. The overall antenna bandwidth, when integrated with the microstrip feed section, is shown to be 40% over which a minimum gain of 11 dBi is demonstrated.

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.

A Simple Equivalent Circuit Model for Ultrawideband Coupled Arrays

Equivalent circuits are proposed to model the radiation impedance of low-profile ultrawideband antenna arrays with strong interelement coupling. Previous approaches provided rudimentary equivalent circuits and referred to much smaller impedance bandwidth arrays. In this letter, we extend these models to include antenna sections that overlap with adjacent array elements (as is the case with interwoven arms of tightly coupled spirals). The proposed equivalent circuits include dielectric superstrates and representations of higher-order grating lobes. Design optimization is carried out for an array of coupled and interwoven antenna elements to develop a 20:1 impedance bandwidth aperture. It is demonstrated that the radiation impedance obtained via the proposed equivalent circuit is in excellent agreement with full-wave simulation.

Low profile and compact size coplanar UWB antenna working from 2.8 GHz to over 40 GHz

AbstractA square monopole coplanar antenna with a circular base is proposed for ultra wideband (UWB) communications. The design parameters are analyzed and optimized to obtain a good performance and the measured return loss below −10 dB is from 2.8 to over 40 GHz. The proposed antenna has advantages of low profile, small size, UWB, and omni‐directional pattern. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 408–411, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24062

Compact UWB monopole for multilayer applications

A novel compact, dual-layer UWB monopole antenna is presented. This low profile ultra-wideband antenna is fed by a 50 Ω shielded strip-line with an array of metal vias making the conducting walls. A printed disc monopole with a circular cut is the radiating element. The dual-layer, shielded strip-line feed allows for integration in multilayer technologies. The ultra-wideband, monopole characteristics of the antenna are confirmed experimentally.

Low‐profile ultra‐wideband antenna for mobile phone applications

AbstractA novel low‐profile ultra‐wideband (UWB) antenna suitable for mobile‐phone applications as an internal antenna is presented. The proposed antenna mainly comprises a planar metal‐plate monopole folded into a low‐profile structure and a matching tuning portion for achieving a very wide operating bandwidth (about 1.89–10.14 GHz in this study). With the very wide bandwidth obtained, the proposed antenna can easily cover the UMTS (1920–2170 MHz) band for mobile communications and the 2.4‐GHz (2400–2484 MHz) and 5.2/5.8‐GHz (5150–5350/5725–5875 MHz) bands for WLAN communications. Characteristics of the proposed UWB antenna applied to a UMTS/WLAN mobile phone are presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 7–9, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20358