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2025-06-06
PIER Letters
Vol. 126, 57-67, 2025
download: 152
Intra- and Peritumoral Radiomics-Based Models for Preoperative Prediction of Lymphatic Vascular Invasion in Invasive Breast Cancer
Lingxia Wang, Weixing Pan, Yitian Wu, Huangqi Zhang, Aie Liu, Enhui Xin, Jiadong Zhang, Lei Chen, Hongjie Hu and Wenbin Ji
In this study, we evaluated the feasibility of intra- and peritumoral artificial intelligence (AI)-based radiomics from Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for preoperative prediction of lymphatic vascular invasion (LVI) in invasive breast cancer (IBC). Our results demonstrated that a radiomic model (area under the receiver operating characteristic curve AUC = 0.951) outperformed a clinical model (AUC = 0.644) in 193 patients. Optimal tumor segmentation using 3D RU-Net (Dice score > 0.75) and 3 mm to 4 mm isotropic 3D peritumoral expansion yielded the strongest predictive performance.
Intra- and Peritumoral Radiomics-based Models for Preoperative Prediction of Lymphatic Vascular Invasion in Invasive Breast Cancer
2025-06-05
PIER Letters
Vol. 126, 49-55, 2025
download: 177
Isosceles Triangle MIMO Antenna for Simultaneous 5G Communications
Mutte Bajibabu, Jetti Babu and Uppalapati Venkata Ratna Kumari
A four-element compact planar MIMO antenna is developed for the 3.5 GHz 5G sub-6 GHz band, ensuring reliable radiation performance and enabling simultaneous downlink and uplink communication. The proposed MIMO system incorporates four isosceles triangular elements, where two are allocated for uplink and the other two for downlink. Its compact structure facilitates simultaneous communication with separate provisions for uplink and downlink operations. The FR4 substrate has four antennas printed orthogonally to minimize mutual interaction between the elements. Triangles are more isolated and efficient when their corners are trimmed. Cutting the semi-circle yields the desired resonance frequencies. The proposed MIMO system measures 90 × 90 × 1.6 mm3. The performance of the proposed system was evaluated using multiple metrics, including far-field radiation patterns, S-parameters, channel capacity loss, envelope correlation coefficient, peak gain, diversity gain, and radiation efficiency. The simulated results closely aligned with the measured data, demonstrating strong agreement.
Isosceles Triangle MIMO Antenna for Simultaneous 5G Communications
2025-05-29
PIER Letters
Vol. 126, 37-48, 2025
download: 278
Low-Profile Reconfigurable UWB Fractal Antenna Enhanced by Parasitic Elements for Wireless Applications
Mohamed Marzouk, Ibrahime Hassan Nejdi, Youssef Rhazi, Mohamed Saih, Jamal Abdul Nasir, Abdulrahman Daher, Mousa Hussein, Zahriladha Zakaria and Ahmed Jamal Abdullah Al-Gburi
This paper presents an enhanced design of a reconfigurable fractal ultra-wideband (UWB) antenna, improved through the inclusion of parasitic elements. The antenna incorporates two plus-shaped parasitic elements and a hexagonal radiating patch, while maintaining compact dimensions of 30 mm × 22 mm × 1.6 mm on an FR4 substrate. A partial ground plane with an integrated rectangular slot is etched on the backside of the resonator. The antenna was designed using HFSS, fabricated, and experimentally validated. The measured results show good agreement with the simulations. It operates over a frequency range of 4 to 10.57 GHz, with resonant frequencies at 4.7, 7.92, and 10 GHz. The design achieves a gain between 2.76 and 5.83 dB and maintains high radiation efficiency ranging from 82% to 95%. To further enhance performance, two strategically placed HPND-4005 PIN diodes are incorporated, allowing tunable resonance characteristics by altering current distribution under various switch configurations. As a result, the reconfigurable antenna extends its operational bandwidth from 3 to 14 GHz, making it suitable for a variety of wireless applications such as Wi-Fi, WiMAX, WLAN, and C-, X-, and Ku-band communications. Notably, the design achieves this wideband reconfigurability using only two PIN diodes while maintaining a compact footprint - offering an advantage over previous designs. Its features support seamless integration into compact electronic devices, enabling manufacturers to incorporate multiple antennas with minimal complexity.
Low-profile Reconfigurable UWB Fractal Antenna Enhanced by Parasitic Elements for Wireless Applications
2025-05-27
PIER Letters
Vol. 126, 31-36, 2025
download: 257
Conception and Fabrication of a New Steerable Microstrip Antenna for ISM Band Applications
Abdelaaziz El Ansari, Shobhit Kisan Khandare, Kaoutar Allabouche, Najiba El Amrani El Idrissi, Zahriladha Zakaria and Ahmed Jamal Abdullah Al-Gburi
This paper presents the conception and fabrication of a new steerable microstrip antenna for ISM band applications. At first, the fundamental antenna element is designed, optimized, and miniaturized to operate at 2.45 GHz, exhibiting a narrow impedance bandwidth and a good gain. However, the standalone element lacks beam steering capability. To enable directional control of its radiation pattern, a novel 3 dB hybrid coupler is used to feed two identical optimized elements, forming a switched array antenna. The resulting configuration achieves a wide impedance bandwidth and improved gain with beam steering capability. The proposed steerable antenna is designed and fabricated on a Rogers RT/duroid 5880 substrate. The simulated results are validated with measured data, showing good agreement and confirming the design's performance.
Conception and Fabrication of a New Steerable Microstrip Antenna for ISM Band Applications
2025-05-05
PIER Letters
Vol. 126, 23-29, 2025
download: 312
Design and Performance Analysis of a Miniaturized Four-Port MIMO Antenna Module for 5G NR and WLAN Bands
Jiaping Lu, Lefei He, Qiangjuan Li and Gui Liu
This paper presents the design and in-depth performance analysis of a miniaturized four-port multiple-input multiple-output (MIMO) antenna module intended for integration on the rear cover of mobile devices. The four antenna elements are configured in a sequential rotation layout and fabricated on a low-profile circular substrate. Each antenna element features an E-shaped patch on the upper side of the substrate, coupled with a rectangular defected ground structure (DGS) on the lower side. A needle-like decoupling mechanism has been incorporated to improve the isolation between the antenna elements. The measured -10 dB impedance bandwidth ranges from 3.5 to 5.45 GHz, successfully meeting the demands of the 5G NR bands N77 (3.3-4.2 GHz), N78 (3.3-3.8 GHz), N79 (4.4-5 GHz), as well as the wireless local area network (WLAN) band (5.15-5.35 GHz). The isolation levels between the antenna elements exceed 17 dB. The average total efficiency is over 40.76%, and the envelope correlation coefficients (ECCs) are maintained below 0.01. The measurement outcomes indicate that the proposed MIMO antenna not only fulfills the requirements for the 5G and WLAN frequency bands but also successfully achieves miniaturization and superior wireless communication performance.
Design and Performance Analysis of a Miniaturized Four-port MIMO Antenna Module for 5G NR and WLAN Bands
2025-04-29
PIER Letters
Vol. 126, 17-22, 2025
download: 318
Compound Dielectric Resonator Antenna
Alexander P. Volkov, Andrey Kobyakov and David R. Peters
A dielectric resonator antenna (DRA) with the resonator body formed, or compounded, by multiple building blocks is proposed. The approach gives flexibility in adjusting the resonator's shape to control input impedance and resonance frequency of the antenna. A simplified method of attaching the resonator's building blocks to the grounded dielectric substrate allowed for reduced fabrication complexity and manual reconfigurability of this compound DRA (cDRA). Several cDRAs with variable resonator sizes were studied theoretically and experimentally.
Compound Dielectric Resonator Antenna
2025-04-26
PIER Letters
Vol. 126, 9-15, 2025
download: 340
3D Printed Waveguide Antenna at X-Band Frequency Band Using MSLA Printing Technology
Huda Bin Abdul Majid, Fahmiruddin Esa, Herdawatie Abdul Kadir, Azka Rehman, Hilman Harun, Muzammil Jusoh, Najib Al-Fadhali, Dian Widi Astuti and Noor Azwan Shairi
Rapid advancements in 3D printing technology have revolutionized antenna fabrication, allowing for the creation of intricate, lightweight, and high-performance structures with exceptional precision. This paper presents the design, fabrication, and experimental evaluation of a 3D-printed waveguide antenna operating in the X-band frequency range (8-11 GHz). The antenna was manufactured using Masked Stereolithography Apparatus (MSLA) technology with Magma X 12 K Dura ABS resin, which was selected for its excellent mechanical strength and dielectric properties. A 0.2 mm thick silver conductive coating was applied to enhance the electrical conductivity and minimize the surface resistance. The proposed antenna is based on a WR-90 rectangular waveguide configuration with an optimized aperture, which ensures minimal reflection loss and high radiation efficiency. Experimental results indicate an impedance bandwidth of 1.34 GHz, spanning from 8.56 GHz to 9.9 GHz, with an optimal resonant frequency at 9.45 GHz. The measured and simulated S11 parameters exhibited strong agreement, validating effective impedance matching and minimal energy dissipation. Furthermore, radiation pattern analysis revealed a directional gain of 6.85 dBi and an overall radiation efficiency of 98.35%. The measured 3 dB beamwidths were 60.5˚ in the E-plane and 105.8˚ in the H-plane, confirming the suitability of the antenna for applications in satellite communication, radar, and wireless sensing. The results demonstrate the viability of MSLA-based additive manufacturing for high-frequency waveguide antennas, offering a cost-effective, lightweight, and high-performance alternative to the traditional fabrication techniques. This study highlights the potential of 3D printing as an innovative approach for the development of next-generation microwave and millimeter-wave communication systems.
3D Printed Waveguide Antenna at X-band Frequency Band Using MSLA Printing Technology
2025-03-19
PIER Letters
Vol. 126, 1-7, 2025
download: 389
An Original Approach to Determine the Minimum Operating Frequency of Mode-Stirred Reverberation Chambers
Lionel Michard, Guillaume Andrieu, Philippe Leveque and Delia Arnaud-Cormos
The minimum operating frequency (MOF) of mode-stirred reverberation chambers is often assessed through statistical analysis using goodness-of-fit (GoF) statistical hypothesis tests such as Anderson-Darling or Kolmogorov-Smirnov. However, in the context of MOF determination, hypothesis tests are typically used with the aim of proving the null hypothesis made on the probability distribution of the electric field in the cavity, as opposed to the initial intent of the tests. A new approach avoiding hypothesis testing is proposed in this work by introducing a criterion based on normalized statistical distances. By normalizing the distances, it has been made possible to limit the influence of the sample size on the assessed minimum frequency, thereby improving the consistency of the results.
An Original Approach to Determine the Minimum Operating Frequency of Mode-stirred Reverberation Chambers