IEEE Open Journal of Antennas and Propagation - OJAP

[Frequency Diverse Array for Signal Geofencing in Wireless Communications: Does it Work?] Simone Del Prete, Marina Barbiroli and Franco Fuschini carry out a detailed analysis of the sensitivity of the geofencing effectiveness to the main array parameters. The analysis covers many aspects of the design, including the selection of the geometrical layout and the number of elements of the array, the frequency increase policy and the frequency offset across the elements and their spacing. The study also discusses the trade-offs between different design choices and provides insights into the performance in terms of focus efficiency and size of the focus area. Results show that bidimensional layouts, e.g., circular or planar, often represent effective solutions, whereas the linear arrangement can be a viable option only in case the frequencies are spread across the elements in a random-like fashion. Read their article here: https://lnkd.in/g2YQSeJi #PhasedArrays #ExtraterrestrialMeasurements #FrequencyDiversity #WirelessCommunication #Interference #AerospaceElectronics #TimeFrequencyAnalysis #APS #IEEE #OJAP

[Dual-Polarized Wideband Filtering Antenna Array Based on Stacked-PCB Structure] Matti Kuosmanen, Sten E. Gunnarsson, Johan Malmström, Juha Ala-Laurinaho, Jari Holopainen and Ville Viikari investigate a thin low-pass filtering antenna array based on dual-polarized Vivaldi elements. The low-pass filtering in the antenna elements reduces the requirement for the front-end filtering between the antenna and the microwave electronics, resulting in improved overall out-of-band suppression, size reduction, and lower cost. The array employs a novel stacked-PCB structure, where simple two-sided PCBs are stacked on top of each other. The via-connected metal layers of all PCBs form a tapered slotline along the surface normal of the PCBs. The filtering effect is realized by corrugating the tapered slotlines, which provides effective, space-saving integration of the filters that fit into a half-wavelength lattice. Read their article here: https://lnkd.in/gucBmtj4 #SlotLines #Filters #MicrowaveAntennaArrays #SlotAntennas #Dispersion #DirectiveAntennas #CutoffFrequency #APS #IEEE #OJAP

[A Metallo-Dielectric Groove Gap Waveguide Slotted Array Antenna With Hybrid Glide-Symmetric Holes & “Mushroom”-Type Metasurfaces] Panagiotis Petroutsos and Stavros Koulouridis present a hybrid multilayer slot array antenna, targeting next-generation wireless communication systems, particularly in mmWave bands like the Ka-band. The hybrid structure utilizes a high-performance metal Groove Gap Waveguide (GGW) feeding network and facilitates the practical manufacturing of slotted antennas and dielectric substrate metasurfaces using printed circuit boards. The proposed antenna incorporates a hybrid glide symmetric holey metasurface into the GGW feeding. This integration addresses assembly challenges between metal and dielectric layers, avoiding delicate welding techniques. It prevents energy leakage between the two different materials, even when a small air gap is maintained between them. Read their article here: https://lnkd.in/gAD-bSfY #AntennaArrays #SlotAntennas #PeriodicStructures #Metals #NonhomogeneousMedia #Metasurfaces #Antennas #APS #IEEE #OJAP

[Advanced Metasurface-Based Antennas: A Review] Wanchen Yang, Jinghao Li, Dongxu Chen, Yue Cao, Quan Xue and @Wenquan Che present a series of combinations of metasurface and antennas from the perspective of design methods and innovative features, which are divided into three sections: performance improvement, function manipulation and other applications. In the section of performance improvement, three typical applications of metasurface are presented, including using non-periodic metasurfaces to raise aperture efficiency, introducing multi-mode resonance metasurfaces to expand bandwidth, and introducing capacitive loading metasurfaces for miniaturization. Read their article here: https://lnkd.in/gd6KsjN4 #Metasurfaces #BroadbandAntennas #ReflectorAntennas #ElectromagneticScattering #SlotAntennas #Antennas #PeriodicStructures #APS #IEEE #OJAP

[Compact Dual-Band Dual-Sense Circularly Polarized Fragmental Patch Antenna Optimized by Improved Simulated-Annealing-Based Algorithm] Tianyu Shu, Bowen Feng, Long Zhang, Chuyue Chen, Hui Chen, Yaling Chen and Qinyu Zhang present a compact dual-band dual-sense circularly polarized (CP) fragmental patch antenna that advanced by an improved simulated-annealing-based optimization algorithm. This design replaces truncated corners of traditional truncated patch antennas with fragmental structures, generating dual-band dual-CP radiation with a small frequency ratio and a high front-to-back ratio. The proposed optimized framework tackles the multi-objective optimization problem through hierarchical optimization to achieve an optimal balance among various performance metrics. Read their article here: https://lnkd.in/g8t-_-_Z #Antennas #Optimization #DualBand #PatchAntennas #PerturbationMethods #Convergence #AntennaArrays #APS #IEEE #OJAP

[Wideband Solar-Cell Integrated Yagi-Uda Antenna] Ahmed Ali, Heesu Wang, Yong Bae Park and Ikmo Park present a wideband ultra-low-profile Yagi-Uda type of solar-cell integrated antenna. The proposed antenna consists of a driver, reflector, and director, and is also designed to function as a solar cell. An ultra-low-profile copper indium gallium selenide (CIGS) based solar cell is used as a driver, and a slit is cut from it to make a built-in solar-cell antenna. A CIGS solar cell-based reflector and director are added to increase the impedance bandwidth and gain of the proposed antenna. A narrow slit is used, and the spacings between the reflector, driver, and director are minimized to increase the solar-cell form factor. A coaxial-to-microstrip line transition type feeding structure is used to excite the antenna, which is printed under the second substrate. Read their article here: https://lnkd.in/gD-8V7QG #PhotovoltaicCells #Antennas #Bandwidth #Impedance #Yagi-Uda antennas #OpticalSensors #RadioFrequency #APS #IEEE #OJAP

[Through-the-Wall Human Activity Recognition Using Radar Technologies: A Review] Jawad Yousaf, Satanai Yakoub, Sara Karkanawi, Taimur Hassan, Eqab R. Almajali, Huma Zia and Mohammed Ghazal presents an in-depth review of Ultra-wideband (UWB) radar systems for recognizing human activities in a room and through-the-wall (TTW) with other diverse applications. After briefly discussing different UWB radar working principles and architectures, the study explores their role in various TTW applications in real-world scenarios. An extensive performance comparison of the legacy studies is presented, focusing on detection tools, signal processing, and imaging algorithms. The discussion includes an analysis of the integration of machine learning models. Read their article here: https://lnkd.in/g68sRBTM #UltraWidebandRadar #RadarAntennas #RadarImaging #RadarDetection #RadarApplications #ArtificialIntelligence #Antennas&Propagation #APS #IEEE #OJAP

[Circular Polarized Dual-Band Wearable Screen-Printed MIMO Antenna Integrated With AMC for WBAN Communications] Arulmurugan S, T R SureshKumar, Johan Sidén and Zachariah Alex propose a novel dual-band circularly polarized MIMO wearable antenna that is screen-printed on a cotton polyester fabric to operate at 2.45 and 5.8 GHz wireless body area network communications. The MIMO fabric antenna is realized with two circularly polarized wearable antennas arranged in orthogonal directions, which provides a less than −10 dB bandwidth of 400 MHz from 2.2 to 2.6 GHz and 800 MHz from 5.3 to 6.1 GHz, with impedance bandwidth of 17 and 14% for lower and higher bands, respectively. The antenna provides an axial ratio bandwidth (below 3 dB) of 3% from 2.4 to 2.47 GHz and 8% from 5.45 to 5.94 GHz. Read their article here: https://lnkd.in/gCSXA762 #Antennas #Polarization #WearableAntennas #ReflectorAntennas #Substrates #DualBand #Bandwidth #APS #IEEE #OJAP

[Spillover Analysis and Mainbeam Characterisation of Arctic Weather Satellite Radiometer Using Method of Moments] by Roland Albers, Mustafa Murat Bilgiç, Karl-Erik Kempe, Alistair Bell and Axel Murk The Arctic Weather Satellite (AWS) is a single instrument mission consisting of a microwave sounder operating in the 54, 89, 183 and 325 GHz bands. The optical design of the instrument consists of a feedcluster directly illuminating a crosstrack scanning mirror, keeping the instrument compact. Due to the simple optics, the beams are not co-aligned and none are in the scanning mirror focal point, leading to beam divergence, asymmetry and scan angle dependent variations in spillover. Using Method of Moment (MoM) simulations of the optics as well as instrument structure, the complete farfield sphere of the instrument can be simulated up to 183 GHz. This paper contains detailed analysis of spillover, beam divergence and intercomparison of physical optics, MoM and nearfield antenna measurements for the mainbeam. Read their article here: https://lnkd.in/g6h429QW #Instruments #Mirrors #Methodofmoments #MicrowaveRadiometry #RemoteSensing #AntennaRadiationPatterns #Satellites #SpaceborneRadar #APS #IEEE #OJAP

[Active Gain-Controlled Beam-Steering Transmissive Surface] Seyed Ehsan Hosseininejad, Amirmasood Bagheri, Fan Wang, Mohsen Khalily, Rahim Tafazolli propose a gain-controlled beam-steering polarization-engineered transmissive surface to tackle the limitation on gain performance for limited space in scenarios for large-distance communication. To implement such a functionality, a transmissive unit cell properly integrated with transistors and phase shifters is introduced with the ability of simultaneous manipulation of phase, amplitude (reduction and amplification), and polarization. Then, a supercell including the array of unit cells with desired linear phase gradient is designed and analyzed using Floquet approach to tilt the transmitted beam. Finally, to verify the proposed idea, a surface including 12×12 unit cells is designed, fabricated and verified. It is demonstrated that a maximum gain of 25 dB compared to air aperture and 11 dB compared to the passive one are achieved by assuming a constant size at 5 GHz. Read their article here: https://lnkd.in/gTGMA9H6  #SurfaceWaves #Transistors #Antennasandpropagation #Gain #Electromagnetics #PhaseShifters #ElectromagneticScattering #APS #IEEE #OJAP