Miniature Ultra-wideband Antenna Research Articles

Unidirective Miniaturized Ultrawideband Antenna for Sensing Buried Objects in Handheld Ground-Penetrating Radar Systems: A design approach

Ground-penetrating radars (GPR) using ultrawideband (UWB) technology have attracted a lot of research interests worldwide for high-resolution sensing and material characterization. This research contribution, therefore, introduces a miniaturized lightweight UWB antenna with high-gain characteristics for applications in handheld GPR systems. The high-gain antenna is developed to function in the 3.13–11.74-GHz wide frequency range such that it can allow high-resolution sensing of buried targets, such as landmines, metal pipes, and other structures. An elliptical quadrant-shaped UWB monopole radiator with a protuberant ground plane is conceptualized to constitute a highly miniaturized antenna of size 18 × 11 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The standalone UWB antenna realizes an impedance bandwidth of 3.07–11.67 GHz with a peak gain of 2.9 dBi. Next, a single-side copper-coated dielectric substrate as a reflector is placed beneath the antenna to attain a significant gain improvement. The proposed design with a reflector provides an average gain improvement of about 7.1 dB without influencing the original bandwidth. For experimental validation, a prototype is fabricated and characterized. The measured performance reveals close agreement with the simulation with an operating bandwidth of 3.19–11.83 GHz and a maximum gain of approximately 10 dBi at 4.02 GHz.

A Miniaturized Thin-Film UWB Monopole Antenna Implemented with High-Dk Adhesive

This paper presents the design of a miniaturized polyimide-based antenna for ultra-wideband (UWB) communication. Miniaturization is achieved through the utilization of adhesive material with a high dielectric constant (high-Dk). The goal of this work is to investigate the impact of such material on the antenna performance and to optimize its design for UWB operation. The manufacturing of the antenna using the proposed structure is developed, and the prototype of an antenna for the UWB high band (6–9 GHz) is measured and analyzed. By leveraging the high Dk of the adhesive material, the simulation and measurement results show that the proposed antenna with a high-Dk adhesive film can achieve compact dimensions with good performance in terms of the gain and time domain characteristics. The results of this study show the potential of exhibiting a reduction in the size of the antenna and will contribute to the advancement of miniaturized UWB antenna technology.

Miniaturization of ultra‐wideband Vivaldi antenna by utilizing double‐layer structure with slots

AbstractIn a Vivaldi antenna, a symmetrical double‐sided structure is introduced to reduce the lower‐side frequency. Multiple transverse and longitudinal slots loaded into the redundant conductor layer of the Vivaldi structure can stimulate resonant modes at the higher frequency end, further broadening the antenna bandwidth towards high frequencies. Meanwhile, impedance matching slots are introduced into the conductor layer on the feed side to achieve ultra‐wideband (UWB) antenna. The overall size of the final antenna is 23.5 mm × 30.0 mm × 2.4 mm, while the relative bandwidth (S11 &lt; –10 dB) reaches 142% (2.49–14.78 GHz). This miniaturized UWB antenna has similar directional patterns in the operating band, with an average gain of 4.82 dB.

Design and analysis of a CPW ‐fed flexible ultrawideband antenna for microwave imaging of breast cancer

This article presents a novel CPW fed ultrawideband (UWB) antenna for detection of unwanted tumor cells in the human breast. Here, a compact and miniaturized UWB antenna employed with dodecagonal edges is proposed for broadening the bandwidth from 2.26 to 13.71 GHz (measured fractional bandwidth of about 143.39%). The antenna is designed on a durable RT 5880 substrate having 0.254 mm thickness, efficiency of 85% and gain of 3.84 dBi. For its flexibility characterization, the prototype of the fabricated antenna is analyzed in both the flat and bending configurations. The simulated testing is carried out by permitting the antenna to emit radiation in conjunction to the human breast phantom to obtain desired antenna characteristics for the microwave imaging (MI) applications. The changes in reflection coefficient with the variation of dielectric content of the breast phantom structure are analyzed. The suggested antenna for MI technique is apt for human exposure because the antenna bids the highest SAR value of 0.932 W/Kg at 10.6 GHz. Moreover, the proposed antenna is flexible, compact and low-profile with low SAR values that can be useful for breast cancer detection.

A Frequency Selective Surface Loaded UWB Antenna for High Gain Applications

This paper presents the design of wideband and high gain Frequency Selective Surface (FSS) loaded antenna for ultra-wideband (UWB) wireless applications requiring high-gain. The antenna consists of a monopole and an FSS reflector. Initially, a conventional rectangular monopole antenna is modified using slot and stub to achieve wide operational bandwidth and size reduction. This modified antenna shows 50% miniaturization compared to a primary rectangular monopole, having a wide impedance bandwidth of 3.6–11.8 GHz. Afterward, an FSS is constructed by the combination of circular and square ring structures. The FSS array consisting of 8 × 8-unit cells are integrated with the antenna as a reflector to enhance the performance of the proposed miniaturized UWB antenna. The loading of FSS results in an improvement of at least 4 dBi gain in the entire operational bandwidth. Moreover, the antenna's bandwidth is also increased at the lower frequency band due to the presence of the FSS. A prototype of the antenna is fabricated and tested to verify the simulation results. The simulation and measurement results show that the antenna offers a wideband –10 dB impedance bandwidth ranging from 2.55–13 GHz with a stable peak gain of 8.6 dBi and retains the radiation pattern stability.

A miniaturized UWB antenna with reconfigurable dual band notch characteristics

In this paper, a miniaturized ultrawideband (UWB) antenna with dual reconfigurable band notch characteristics is proposed. Band rejections at 5G (3.3−4.4 GHz)/WiMAX (3.3−3.6 GHz) and WLAN (5.150−5.825 GHz) are obtained by introducing two C-shaped slots on the radiating patch of the antenna. Reconfigurable dual band notch function is achieved by integrating two PIN diodes on the slots. By etching a nested structure of C-shaped slots, an efficient top-cut circular-shaped radiating patch is designed, which realizes a compact size of 18.0 mm×19.5 mm. The proposed antenna operates in 4 states in the case of common interference scenarios. The simulated and experimental results show that the bandwidths of notch bands in single band notch states are 3.2−4.9 GHz and 5.2−6.0 GHz respectively, while the bandwidths of notch bands in dual band notch state are 3.25−4.75 GHz and 5.3−6.1 GHz. The antenna also exhibits a good radiation pattern with a maximum peak gain value of 2.8 dBi. dBi.

A Negative Index Metamaterial to Enhance the Performance of Miniaturized UWB Antenna for Microwave Imaging Applications

A new, compact planar wideband negative index metamaterial based on a modified split ring resonator (SRR) is studied to enhance performance of ultrawideband antenna. A compact, metamaterial (MTM)-inspired microstrip antenna is presented for microwave imaging system (MIS) application. Two layers of left-handed metamaterial array (2 × 4) of the unit cell are placed on the radiating patch and the ground plane, respectively. Each left-handed metamaterial (LHM) unit cell was constructed by modifying a square split ring resonator (SRR), resulting in negative permeability and permittivity with a stable negative refractive index. The results shows that it has a significant impact on the performance of conventional patch antenna in terms of transmission co-efficient, efficiency and low loss. Compared to antenna without LHM, it is shown that the bandwidth is significantly broadened up to a few megahertz and becomes more convergent leading to the achievement of desired properties for ultra-wideband (UWB) applications leading to microwave imaging. The proposed MTM antenna structure is fabricated on commercially-available, flame-retardant material of size 26 × 22 × 1.6 mm3 with 4.6 dielectric constants, due to its low cost and convenience for making multilayer printed circuit boards (PCBs). The antenna achieves 3.1 GHz to 10.71 GHz of impedance bandwidth (−10 dB), which covers the full UWB band. The use of double-layer negative index MTM unit cells enhances UWB performance, and the improved radiation efficiency, nearly directional radiation pattern, acceptable gain, stable surface current and negative refractive index make this MTM antenna a suitable candidate for UWB applications.

A MINIATURIZED VOLKSWAGEN LOGO UWB ANTENNA WITH SLOTTED GROUND STRUCTURE AND METAMATERIAL FOR GPS, WIMAX AND WLAN APPLICATIONS

A novel concept of using slotted ground structure and a single circular split ring resonator (SRR) to achieve multiband operation from a miniaturized UWB antenna is presented in this paper. Initially, a miniaturized Volkswagen logo ultrawideband (UWB) antenna having −10 dB impedance bandwidth of about 124% (2.9–12.4 GHz) in simulation and 116.7% (3.1–11.8 GHz) under measurement is designed. This miniaturization leads to about 10% increment in −10 dB reflection coefficient bandwidth and about 66.71% reduction in the volume of the proposed UWB antenna as compared to the conventional circular antenna. In order to reconfigure the proposed UWB antenna to operate it at 1.5 (GPS), 3.5 (WiMAX), 5.2 and 5.8GHz (WLAN) frequency bands, slotted ground structure with metamaterial is used. The proposed metamaterial is a circular SRR consisting of a single circular ring and is placed on the slotted ground structure of the proposed antenna to achieve 1.5GHz band. The proposed configuration has a volume of 0.290λ0 × 0.290λ0 × 0.015λ0 (30 × 30 × 1.6mm3) at a lower resonating band of 2.9GHz and is fabricated on a widely available FR4 substrate with a loss tangent of 0.02 and dielectric constant of 4.4. Simulated and experimental results show that the proposed design yields S11 < −10 dB at the targeted frequencies. Good impedance matching, stable radiation characteristics with cross-polarization level less than −15 dB (both in E and H planes), VSWR < 2, average gain of 3.09 dBi and radiation efficiency of more than 85% are observed at the designed band when the antenna is fabricated and tested.

UWB antenna based on SCRLH-TLs for portable wireless devices

A novel miniature ultrawideband antenna is proposed that exhibits excellent radiation characteristics. The antenna is based on the simplified composite right/left-handed transmission-lines (SCRLH-TLs) that are implemented using F-shaped and T-shaped slits on the antenna's ground-plane and radiating arms, respectively. The coplanar waveguide feed-line is impedance matched to the radiating patches using H-shaped microstrip stub. The antenna operates between 0.65 and 9.2 GHz, which corresponds to an impedance bandwidth of 173.6%. The maximum gain and efficiency measured are 3.5 dBi and 70% at 4.5 GHz, respectively. The antenna dimensions are 25 × 15 × 1.6 mm3 or 0.054λ0×0.032λ0×0.003λ0, where λ0 is free-space wavelengths at 0.65 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:69–71, 2016

A Miniaturized UWB Antenna for Wireless Dongle Devices

In this letter, a planar ultra wideband (UWB) antenna suitable for the integration in wireless universal serial bus (USB) dongles is described. The antenna has a bandwidth equal to 2 GHz from 3 GHz up to 5 GHz with return loss values below -10 dB in the whole frequency range. To comply with UWB system needs, the antenna presents good distortionless properties when employed in a TX/RX system. Moreover, thanks to its simple shape and miniaturized geometry, the proposed prototype can be easily integrated and printed on dongle PCBs. In order to assess the reliability and efficiency of the antenna, a selected set of results from the experimental validation are shown and compared with the outcomes of the numerical simulations carried out during the synthesis process.