| Metadata | Details |
|---|
| Publication Date | 2020-03-01 |
| Journal | Sensors |
| Authors | Amran Hossain, Mohammad Tariqul Islam, Ali F. Almutairi, Mandeep Singh Jit Singh, Kamarulzaman Mat |
| Institutions | National University of Malaysia, Kuwait University |
| Citations | 44 |
| Analysis | Full AI Review Included |
- Core Achievement: Development of a highly compact (29 x 24 x 1.5 mm3) Ultrawideband (UWB) antenna utilizing octagonal ring-shaped parasitic resonators and a slotted ground plane, optimized for Microwave Imaging (MWI).
- Bandwidth Performance: Achieved an extensive impedance bandwidth of 8.7 GHz (2.80-11.50 GHz) for a reflection coefficient (S11) less than -10 dB, corresponding to a fractional bandwidth of 121.67%.
- Gain and Efficiency: The prototype delivers a maximum gain of 5.8 dBi (at 9.45 GHz) and maintains a high average radiation efficiency of 75% across the entire operating band.
- MWI Optimization: The design generates three critical resonance frequencies (3.50 GHz, 6.45 GHz, and 10.20 GHz), which are essential for balancing high-resolution imaging (higher frequencies) and deep tissue penetration (lower frequencies).
- Design Methodology: Performance enhancement relies on three octagonal parasitic elements, a staircase diamond-shaped radiating patch, and a partial ground plane featuring rectangular and irregular staircase-shaped zigzag slots.
- Time Domain Validation: The antenna exhibits superb time-domain characteristics, confirmed by a high Fidelity Factor (FF) of 0.9091 in the Face-to-Face (F2F) setup, indicating minimal signal distortion.
| Parameter | Value | Unit | Context |
|---|
| Overall Dimensions (L x W x h) | 29 x 24 x 1.5 | mm3 | Compact prototype size |
| Substrate Material | FR-4 | N/A | Low-cost epoxy resin fiber |
| Relative Permittivity (Δr) | 4.3 | N/A | Substrate property |
| Loss Tangent (tan(ÎŽ)) | 0.02 | N/A | Substrate property |
| Operating Frequency Range | 2.80 - 11.50 | GHz | S11 less than -10 dB |
| Impedance Bandwidth | 8.7 | GHz | Total UWB coverage |
| Fractional Bandwidth (FB) | 121.67 | % | UWB suitability |
| Maximum Gain | 5.8 | dBi | Achieved at 9.45 GHz |
| Average Radiation Efficiency | 75 | % | Over the radiating bandwidth |
| Maximum Radiation Efficiency | 82 | % | Peak performance |
| Primary Resonance Frequencies | 3.50, 6.45, 10.20 | GHz | Crucial for MWI resolution/penetration |
| Fidelity Factor (FF) | 0.9091 | N/A | Face-to-Face (F2F) scenario |
| Feed Line Impedance | 50 | Ω | SMA connector matching |
- Initial Design and Substrate Selection: The antenna was designed on a minimal cost FR-4 substrate (h=1.5 mm, Δr=4.3). Initial dimensions were calculated based on the lowest operational frequency (2.80 GHz) using standard patch antenna equations.
- Radiating Patch Structure: A diamond-shaped radiating patch, modified with five incremental staircase rectangular sections, was used as the main radiating element to enhance bandwidth through electronic coupling with the ground plane.
- Front Parasitic Element Integration: Two identical octagonal, rectangular slotted ring-shaped parasitic elements were placed symmetrically alongside the 50 Ω feed line on the topside. A 0.5 mm gap was maintained to reduce inductive reactance and increase capacitance, thereby boosting bandwidth.
- Back Parasitic Element Integration: A third, larger octagonal, rectangular slotted ring-shaped parasitic element was placed in the middle of the backside of the substrate to increase radiation directivity and improve gain.
- Ground Plane Slotting (Top): Three rectangular slots were cut out at the top of the partial ground plane (H=7 mm) to adjust electromagnetic coupling effects, improving the reflection coefficient (S11) and gain.
- Ground Plane Slotting (Bottom): Two irregular staircase-shaped zigzag slots were etched at the bottom of the ground plane. This fractal-inspired slotting technique was used to control current distribution, enhance radiation directivity, and generate the required multiple resonance frequencies.
- Corner Chamfering: The bottom corners of the ground plane were chamfered (x=2.83 mm) to alter the current path diagonally, successfully shifting the upper operating frequency band from 11.0 GHz to 11.5 GHz.
- Simulation and Optimization: The entire structure was designed and optimized using the 3D electromagnetic simulator CST Microwave Studio 2018.
- Measurement Validation: Frequency domain measurements (S11) were performed using an Agilent N5227A PNA network analyzer. Radiation patterns, gain, and efficiency were measured using the UKM Satimo near field StarLab system.
- Time Domain Analysis: The Fidelity Factor (FF) and group delay were calculated for three transmission scenarios (F2F, SbS X-axis, SbS Y-axis) to confirm suitability for short-pulse UWB applications.
- Medical Microwave Imaging (MWI): Primary application for non-invasive, non-ionizing detection of tumors (e.g., breast cancer, brain tumors) by exploiting the dielectric contrast between healthy and malignant tissue.
- High-Resolution Diagnostic Sensing: The generation of multiple resonance frequencies (up to 10.20 GHz) allows for high-resolution image reconstruction, while the lower frequencies ensure adequate penetration depth into biological tissues.
- Ultra-Wideband (UWB) Radar and Communication: Applicable in short-range, high data rate wireless communication systems and radar sensing due to its wide bandwidth and compact form factor.
- Portable Sensing Systems: The compact size (29 x 24 mm) and use of low-cost FR-4 substrate make the antenna suitable for integration into portable, handheld diagnostic and sensing devices.
- Through-Material Detection: The directional radiation pattern and high gain enable applications in industrial or security sensing, such as through-wall imaging or non-destructive testing.
View Original Abstract
An Ultrawideband (UWB) octagonal ring-shaped parasitic resonator-based patch antenna for microwave imaging applications is presented in this study, which is constructed with a diamond-shaped radiating patch, three octagonal, rectangular slotted ring-shaped parasitic resonator elements, and partial slotting ground plane. The main goals of uses of parasitic ring-shaped elements are improving antenna performance. In the prototype, various kinds of slots on the ground plane were investigated, and especially rectangular slots and irregular zigzag slots are applied to enhance bandwidth, gain, efficiency, and radiation directivity. The optimized size of the antenna is 29 Ă 24 Ă 1.5 mm3 by using the FR-4 substrate. The overall results illustrate that the antenna has a bandwidth of 8.7 GHz (2.80-11.50 GHz) for the reflection coefficient S11 < â10 dB with directional radiation pattern. The maximum gain of the proposed prototype is more than 5.7 dBi, and the average efficiency over the radiating bandwidth is 75%. Different design modifications are performed to attain the most favorable outcome of the proposed antenna. However, the prototype of the proposed antenna is designed and simulated in the 3D simulator CST Microwave Studio 2018 and then effectively fabricated and measured. The investigation throughout the study of the numerical as well as experimental data explicit that the proposed antenna is appropriate for the Ultrawideband-based microwave-imaging fields.
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