In this paper, a wideband antenna is proposed for ultra-wideband microwave imaging applications. The antenna is comprised of a tapered slot ground, a rectangular slotted patch and four star-shaped ...parasitic components. The added slotted patch is shown to be effective in improving the bandwidth and gain. The proposed antenna system provides a realized gain of 6 dBi, an efficiency of around 80% on the radiation bandwidth, and a wide impedance bandwidth (S11 < -10 dB) of 6.3 GHz (from 3.8 to 10.1 GHz). This supports a true wideband operation. Furthermore, the fidelity factor for face-to-face (FtF) direction is 91.6%, and for side by side (SbS) is 91.2%. This proves the excellent directionality and less signal distortion of the designed antenna. These high figures establish the potential use of the proposed antenna for imaging. A heterogeneous breast phantom with dielectric characteristics identical to actual breast tissue with the presence of tumors was constructed for experimental validation. An antenna array of the proposed antenna element was situated over an artificial breast to collect reflected and transmitted waves for tumor characterization. Finally, an imaging algorithm was used to process the retrieved data to recreate the image in order to detect the undesirable tumor object inside the breast phantom.
A new design of a triple band perfect metamaterial absorber based on Pythagorean fractal geometry is proposed and analyzed for terahertz sensing applications. The proposed design showed an enhanced ...sensing performance and achieved three intensive peaks at 33.93, 36.27, and 38.39 THz, corresponding to the absorptivity of 98.5%, 99.3%, and 99.6%, respectively. Due to the symmetrical nature of the recommended design, the structure exhibited the characteristics of independency on the incident wave angles. Furthermore, a parametric study was performed to show the effects of the change in substrate type, resonator material, and substrate thickness on the absorption spectrum. At a fixed analyte thickness (0.5 μm), the resonance frequency of the design was found to be sensitive to the refractive index of the surrounding medium. The proposed design presented three ultra-sensitive responses of 1730, 1590, and 2050 GHz/RIU with the figure of merit (FoM) of 3.20, 1.54, and 4.28, respectively, when the refractive index was changed from 1.0 to 1.4. Additionally, the metamaterial sensor showed a sensitivity of 1230, 2270, and 1580 GHz/μm at the three resonance frequencies, respectively, when it was utilized for the detection of thickness variation at a fixed analyte refractive index (RI) of 1.4. As long as the RI of the biomedical samples is between 1.3 and 1.4, the proposed sensor can be used for biomedical applications.
In this paper, a new design of microstrip power limiter which is based on microstrip technology and zero bias Schottky diode is introduced. In this context, the FR‐4 substrate that was characterized ...by dielectric permittivity (4.4), dielectric thickness (1.6 mm), and the HSMS 286k Schottky diode is used to design the proposed power limiter. The planar resonators are designed, optimized, and simulated with the shunting of the HSMS 286k diodes by using Schematic solver integrated in ADS from Agilent Technologies. The simulation results are significant in terms of high impedance matching, strong insertion of the low power, and good limitation ratio of the high power. The proposed power limiter is fabricated and tested in the measurement part. It is observed that the results are in agreement with the numerical analysis in terms of matching, isolation, and power limitation. The achieved microwave power limiter offers simple construction, small size (44 × 40 mm2), wide bandwidth, and good limitation ratio less than 10 dBm when the input power reaches 30 dBm.
In this research work, a symmetrical four-capacitance loaded complementary circular split ring resonator is proposed, which uses an ultra-thin Zinc Selenide (ZnSe) substrate to realize a low-profile ...triple-band metamaterial (MTM) perfect absorber for application in the terahertz (THz) frequency range. The electromagnetic properties of the proposed structure were calculated and investigated using the Finite Integration Technique (FIT). The proposed structure exhibited three highly absorptive (nearly perfect) peaks at the resonance frequencies of 15.68 THz, 37.48 THz, and 39.55 THz. Furthermore, the absorber was found to be insensitive to the polarization and incident wave angles, due to its symmetrical design. The effects of the conductor type, substrate thickness, unit cell dimension, resonator gap, and substrate type on the reflection and absorption spectra were investigated. To validate the numerical results, the proposed design was analyzed using High-Frequency Simulation Software (HFSS) and Advanced Design System (ADS). The surface current, electric field, and magnetic field distributions at the three-resonance frequency were analyzed. It was concluded that the overall performance of the proposed MTM structure was superior compared to those reported in the literature. The proposed design could be a good candidate for application in stealth technology, imaging, and thermal energy harvesting.
This paper presents the design strategy of a microwave low noise amplifier (LNA) in microstrip technology for sub-6 GHz 5G communication systems. A microstrip coupler is exploited to design a DC ...block in order to avoid unwanted parasitic effects generated by lumped elements and to facilitate fabrication. Bias and matching networks are implemented using microstrip transmission lines. Based on the designed circuit, a prototype is fabricated and measured using an Agilent Technologies (hp)® ATF13786 field effect transistor. The proposed LNA is simulated and measured at 3.5 GHz. The results demonstrate that the proposed LNA achieves high gain of 12.7 dB, noise figure less than 2 dB, input and output reflection coefficients less than –10 dB, and unconditional stability over the desired bandwidth. Regarding the large signal results, the proposed LNA yields excellent performance with an output power of 16.4 dBm, and a power added efficiency (PAE) of 18%. Furthermore, the proposed LNA exhibits good linearity with an output compression point at 1 dB (OP1dB) of 0 dBm, and a third-order intercept point (OIP3) greater than +37.7 dBm.
In this study, various breast phantom (BP) models for microwave breast imaging (MBI) are investigated and the creation and assessment of designed models are presented. Symmetrical and asymmetrical BP ...models have been constructed. based on 3D printed structures stuffed with various mixed material combinations that roles various breast tissue layers (skin, healthy fat tissue, glandular tissue, heterogeneous mix tissue, and tumor tissue) in terms of permittivity over the ultra-wide band frequency (3.1-10.6GHz) range. However, the main issue in making such phantoms is coming up with adequate material mixes that mimic those characteristics across the frequency band, as well as creating the phantom with realistic approach. The complex dielectric characteristics are tested after fabrication with a dielectric probe kit coupled to a VNA. Then, the measured complex dielectric properties are compared to the real human breast dielectric values. The symmetrical and asymmetrical phantoms' integrated structure allows the tumor and BPs to be dynamically combined to provide a test setup based on MBI technologies. Once the breast phantom has been produced, antenna arrays are positioned around it to collect scattering parameter data for tumor characterization. Finally, the extracted feature data was used to reconstruct the image in order to find the undesirable tumor component within the breast phantom using an imaging algorithm.
•Suggested antenna has a wider BW of 7 GHz (4.1–9.7 GHz).•Good radiation efficiency of more than 85% and realized gain of 5.1 dBi are obtained.•Small size, high gain and UWB capability, the antenna ...is a strong candidate for MWI applications.•The antenna performs admirably in both frequency and time domains with a good fidelity factors of 73% in FtF and acceptable value of 56.7% in SbS.
In this work, a small multilayer ultra-wideband (UWB) patch antenna for microwave breast imaging (MWI) applications was developed both theoretically and experimentally. However, to improve the antenna performance relating to the bandwidth (BW), the radiating element of the suggested initial antenna is modified by adding a modified split ring resonator (SRR) and slits in the patch as well as the ground plane. Then, to achieve the requisite antenna properties for MWI applications such as the gain and directivity, the antenna is equipped with a uniplanar artificial magnetic conductor (AMC) structure made up of a 3 × 3 array of square modified SRR unit cells. The final proposed prototype has a relatively small size of 20 × 19 × 1.6 mm3 and it accomplishes a return loss below -10 dB (S11< -10 dB) at overall BW of 7 GHz (4.1 – 9.7 GHz) with more than 5 dBi realized gain. In this way, the characteristics of the fabricated antenna are measured to examine the antenna performance. Indeed, the fidelity factor of face-to-face (FtF) and side-by-side (SbS) scenarios are also noticed for the same frequency range. In the final analysis, a simulation model of the antennas, which operate as a transceiver, and a breast phantom model with tumor sample are proposed for detecting cancerous tumor cells within the breast.
Hence, the proposed design is suitable in the biomedical applications such as tumor cell detection.
A small ultra-wideband (UWB) patch antenna for microwave breast imaging (MWI) applications is shown off in this paper. However, to improve the antenna performance relating to the bandwidth (BW), the ...radiating element of the suggested antenna is modified by adding slits in the patch as well as the ground plane. The proposed prototype has a relatively small size of 20 × 19 × 1.6 mm3 and it accomplishes a return loss below −10 dB (S11< −10 dB) at an overall BW of 7 GHz (4–11 GHz) with more than 3 dBi realized gain. The antenna is designed and simulated by using a finite integration technique-based simulator. In this way, the characteristics of the fabricated antenna are measured to examine the antenna performance. Indeed, the fidelity factor of face-to-face (FtF) and side-by-side (SbS) scenarios are also noticed for the same frequency range. In the final analysis, a simulation model of the antennas, that operate as a transceiver, and a breast phantom model with tumor sample is proposed for detecting cancerous tumor cells within the breast. Hence, the proposed approach is suitable for UWB based MWI applications in tumor cell detection.
A compact wideband band‐pass microstrip filter based on triangular split ring resonators is presented. The center frequency of the proposed structure is 3.1 GHz and the 3 dB bandwidth results 1.05 ...GHz. Good agreements between the simulated and measured results demonstrates the effectiveness of the proposed design. The size of the filter is 14 × 50 mm2 only.
