Recent Articles
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On Embedded Element Radiation Function and Beam Direction of Wide-Scanning Array Antennas
28 June 2024 Prabhat Khanal and Jian Yang presents a rigorous new analytical derivation of the theorem on the embedded element radiation function of ideally infinite planar array antennas, along with a formula for accurately calculating the main beam direction of finite-sized array antennas based on the theorem. It validates the previously established formula of the embedded element radiation function, where the amplitude is proportional to cosθ, based on the intuitive reasoning that the effective area of an element should be proportional to its projected area in the direction of interest angle θ, provided that the array antenna has no grating lobes for the full scan, no surface waves, no losses, and active impedance matched.
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Optimal Design of Low Sidelobe Sparse Linear Arrays
20 June 2024 Li Wang, Fenggan Zhang and Banghuan Hou propose an improved Differential Evolution (DE) algorithm integrating the Cauchy-Gauss mutation strategy to optimize the antenna performance in a sparse linear array (SLA) subject to specific constraints of the antenna aperture, number of elements and element spacing. The initial value of the algorithm is generated through the chaotic Piecewise map, while the scaling factor is adjusted dynamically in line with the iterations and fitness values.
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3-D-Printed Encapsulated Dielectric Resonator Antennas With Large Operation Frequency Ratio for Future Wireless Communications
18 June 2024 Reza Shamsaee Malfajani, Reza Damansabz, Sampada Bodkhe, Daniel Therriault, Jean-Jacques Laurin and Mohammad S. Sharawi introduce a novel Encapsulated Dielectric Resonator Antennas (E-DRAs) designed for operation at sub-6-GHz and mm-wave bands for 5G and beyond applications. The DRA part of the antenna consists of an array of small cylindrical DRAs (cDRA) encapsulated in a larger cylinder. At mm-wave band, the small cDRAs are radiating elements while the larger cylinder acts as a lens to enhance the gain and provide beam switching at discrete angles by switching the feed between the small cDRAs. At sub-6-GHz band, the large cylinder is the main radiator.
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Unbalanced-Fed TCDA Performance Improvement Using a Scan Impedance Model
12 June 2024 Eric D. Robinson and Carey M. Rappaport present a scan impedance model which describes performance in terms of a combination of even and odd monopole and dipole radiating modes. An intermodal coupling term is included to account for performance when scanning in the E-plane. Each mode is calculated individually in a full-wave solver and the model is then validated by comparing the proposed combination to a full simulation of the unbalanced-fed TCDA. A coaxial extension technique is then introduced to increase the impedance of the monopole-like radiating even mode, allowing the unbalanced-fed array to match the performance of the balanced-fed version without shorting posts or significant redesign of the elements or lattice.
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Consequences of the Potential Gauging Process for Modeling Electromagnetic Wave Propagation
12 June 2024Thomas Reum presents this predominantly theoretical article that focuses on a qualitative discussion of peculiarities, which are introduced in practical electromagnetic (EM) wave propagation scenarios when the gauge for the electrodynamic potentials is not chosen in accordance to the appropriate space-time metric of the underlying physical framework. Based on ordinary vector calculus, this is done for the viewpoint of radio frequency (RF) engineers by using two examples of guided EM waves: one large-scale case of a terrestrial scenario and one small-scale case involving a device level setup. Readers may benefit especially from this practical orientation, since gauging is often analyzed primarily mathematical by solely arguing on terms of equations instead of discussing concrete applications.
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A Single Radiator-Based Circularly Polarized Antenna for Indoor Wireless Communication Applications
12 June 2024 Heng-Tung Hsu, Yi-Fan Tsao and Arpan Desai introduce a novel technique for inducing circular polarization in a single radiator through the implementation of a sequentially rotated feeding network. Analogous to the operational principles of sequentially rotated antennas employing multiple radiators, the creation of circular polarization (CP) with a solitary radiator becomes achievable through the distinctive phase and angular arrangement facilitated by the feeding network. This innovative approach not only results in a substantial reduction in complexity but also contributes to an overall reduction in antenna size, all while upholding commendable CP performance in terms of both axial ratio (AR) bandwidth and beamwidth.
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State of the Art on Advancements in Wireless Capsule Endoscopy Telemetry: A Systematic Approach
05 June 2024 Sara Fontana, Simona D’Agostino, Alessandra Paffi, Paolo Marracino, Marco Balucani, Giancarlo Ruocco, Salvatore Maria Aglioti, Francesca Apollonio and Micaela Liberti prepare this systematic review according to PRISMA guidelines focuses on the main technological advances of data transmission from the in-body ingestible capsule to an external receiver in Wireless Capsule Endoscopy (WCE). A total of 142 studies were screened from a comprehensive literature search, performed in Scopus, Science Direct, and IEEE Xplore database. A final number of 47 met the inclusion criteria and were included in the review. The results highlight innovative technologies to optimize the wireless link efficacy and safety to an external receiver. High gain, wideband, omnidirectional radiation pattern, and low levels of specific absorption rate (SAR) are of crucial importance.
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Sub-THz Conformal Lens Integrated WR3.4 Antenna for High-Gain Beam-Steering
1 June 2024 Akanksha Bhutani, Joel Dittmer, Luca Valenziano and Thomas Zwick demonstrates the first conformal lens-integrated rectangular waveguide antenna that achieves high-gain beam-steering in the sub-THz range of 230 GHz to 330 GHz, to the best of the authors’ knowledge. The antenna consists of a 2×32 array of elliptical slots (E-slots) fed by a standard WR3.4 rectangular waveguide, ensuring that the antenna operates in its dominant TE10 mode. The E-slots are spaced by less than half of the guided wavelength, which causes them to be fed with a constant phase difference, thus leading to a progressive phase shift along the antenna aperture. Consequently, the antenna main lobe steers from -71° to -16° as the operating frequency varies from 230 GHz to 330 GHz, respectively.
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Sub-GHz Wrist-Worn Antennas for Wireless Sensing Applications: A Review
06 May 2024 Sanjeev Kumar, Gholamhosein Moloudian, Roy B. V. B. Simorangkir, Dinesh R. Gawade, Brendan O’Flynn and John L. Buckley review wrist-worn Sub-GHz antennas reported in the literature, analyzing key antenna parameters such as antenna topology, size, impedance bandwidth, peak realized gain, radiation efficiency, and specific absorption rate (SAR). Additionally, it underlines antenna design challenges, limitations, current trends, and presents potential future perspectives.
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Analysis and Design of Planar Surface Wave Lenses and Application to Leaky-Wave Antennas
19 February 2024 Maksim V. Kuznetcov, Davide Comite, Symon K. Podilchak, Alois P. Freundorfer and Yahia M. M. Antar present planar metasurface lens structures based on microstrip technology, optimized to control the propagation of surface waves (SWs). Two different lenses are studied, i.e., a converging or plane-wave-like lens and a diverging lens. Near-field simulations and measurements are reported to demonstrate the guiding features of the designed lenses, which have also been proposed as a feeding system for planar leaky-wave antennas (LWAs). Far-field results show improvements in terms of reduced cross polarization and sidelobe level as well as increased realized gain when compared without these SW lenses.