Additional Articles

Antenna Design for the Arctic Weather Satellite Microwave Sounder

14 July 2023 Roland Albers, Anders Emrich, and Axel Murk propose an antenna design for the Arctic Weather Satellite (AWS), a prototype mission for an operational constellation of microwave sounders, complimenting existing meteorological sounders. The AWS is a microsatellite with a single cross-track scanning radiometer operating in the 54, 89, 183 and 325 GHz bands. Due to the small platform size, the core design focus of the radiometer’s quasi-optics is less complexity and a more compact setup than comparable spaceborne microwave sounders. The main challenge for instrument performance is that only one of the four horns can be located in the focus of the scanning reflector. Consequently, scan angle dependent spillover variations and beam asymmetries can occur. This paper details the simulation and optimisation efforts of the quasi-optics to minimise the aforementioned effects.

Tuning the Angular Characteristics of Biomimetic Antenna Arrays

11 July 2023 Ines Dorsch Dominik Schwarz, Sarah Forster, and Christian Waldschmidt present the concept and the design process of a tunable Biomimetic Antenna Arrays (BMAA). By electronically tuning varactor diodes, such an array can adapt its angular characteristics depending on the direction-of-arrival (DoA) and signal strength of a radar target. The theoretical requirements for the desired task are examined with general S-parameter simulations. Extensive circuit simulations of a proposed architecture unveil a variety of achievable designs of tunable BMAAs. Radar measurements of different implementations in the 77 GHz range and the theoretical analysis are in good agreement.

Receive Mode Time-Modulated Antenna Array Incorporating Subsampling—Theoretical Concept and Laboratory Investigation

07 July 2023 Edward A. Ball, Sumin David Joseph and Alan Tennant present an eight element Subsampling Time Modulated Array (STMA) operating in receive mode with a carrier at 2.4 GHz using bespoke Radio Frequency (RF) hardware. Each STMA cell incorporates subsampling functionality, with the sampling frequency significantly below the carrier frequency and requiring minimal additional hardware. By using this concept, the hardware required for a receiver incorporating an antenna array can be reduced and costs saved. STMA design equations and architecture strategies are presented, and a prototype hardware demonstrator is introduced.

A Dual Wide-Band Mushroom-Shaped Dielectric Antenna for 5G Sub-6-GHz and mm-Wave Bands

05 July 2023 Reza Shamsaee Malfajani, Hamed Niknam, Sampada Bodkhe, Daniel Therriault, Jean-Jacques Laurin and Mohammad S. Sharawi present the design and implementation of a dual wide-band mushroom-shaped antenna. The antenna consists of a cylindrical dielectric resonator (cDRA), a cylindrical dielectric rod as a waveguide (cDR), and a dielectric lens (DL). The cDRA in conjunction with the DL acts as a sub-6-GHz antenna. At the mm-wave band, the small cDR acts as a waveguide, which transfers the wave from the feed toward the larger cDRA and the DL in order to produce a high gain.

A Diffusion Model for Multi-Layered Metasurface Unit Cell Synthesis

04 July 2023 Chen Niu, Mario Phaneuf, and Puyan Mojabi propose a deep learning approach based on a diffusion model to yield metasurface unit cell designs. This method takes desired two-port scattering parameters along with the frequency of operation in an attempt to synthesize three-layered metasurface unit cells. The core of this approach lies in casting the three-layered unit cell synthesis process as conditional three-channel binary image synthesis. The conditions are governed by the desired scattering parameters at a given frequency whereas the binary nature implies the presence and absence of metallic traces.

A Deep Learning-Based Approach to Design Metasurfaces From Desired Far-Field Specifications

04 July 2023 Chen Niu, Mario Phaneuf, Tianke Qiu and Puyan Mojabi develop a deep learning neural network model in conjunction with a method to incorporate auxiliary surface waves for the macroscopic design of transmitting metasurfaces. The main input to the neural network model is the user-defined desired far-field specifications. This network is used to calculate the required tangential electromagnetic fields on the metasurface. These fields will then be augmented by incorporating auxiliary surface waves along the metasurface for power redistribution to satisfy the requirement for having lossless and passive metasurfaces.

Statistical Evaluation of the Role of GNSS Signal Propagation Orientation in Low-Latitude Amplitude Scintillation Severity

30 June 2023 Alison Moraes, Jonas Sousasantos, Bruno J. Affonso, Paulo R. P. Silva, Eurico R. De Paula and João F. G. Monico perform an analysis considering aspects of the orientation of the propagation of the radio signals through the plasma bubbles structures to evaluate how this geometry can affect the scintillation profile. The dataset covers five months of records from three stations over the Brazilian region during the last solar cycle maximum. The initial results indicate that propagation paths fully aligned are consistently related to larger values of S4 and more severe scintillation.

Physics-Based Coherent Modeling of Long-Range Millimeter-Wave Propagation and Scattering in Rain

12 June 2023 Behzad Yektakhah and Kamal Sarabandi present a fast and accurate numerical method for phase coherent modeling of wave propagation and scattering in random media, like rain. In this approach, the random medium is divided into sufficiently large finite slabs and each slab is modeled as a network with multiple input/output ports where ports represent rays with different polarizations propagating in different directions entering and leaving the slabs. The proposed method considers multiple scattering among all scatterers and thus the entire physics of wave-particle interactions is accounted for.

Bandwidth Enhancement of Low-Profile Metasurface Antenna Using Nonuniform Geometries

08 June 2023 Hayden A. Banting and Carlos E. Saavedra investigate artificial magnetic conductor metasurface antennas using a robust, surrogate-assisted, differential evolution optimization technique. Using a uniform metasurface array configuration as a starting point, multiple array configurations are parameterized and the differential evolution optimizer yields nonuniform array geometries exhibiting wideband performance. Two prototypes are fabricated and characterized to experimentally confirm the advantages of proposed designs.

Post-Fabrication Technique to Manage Material Variations in 3-D Printed Microstrip Antenna Substrates

08 June 2023 Zere Iman, Zubair Akhter, Yiyang Yu and Atif Shamim present a post-fabrication technique capable of compensating for variations in the εr of 3D printed substrates, focusing on microstrip patch antennas (MPAs). The proposed technique, suitable for correcting the fr of a single microstrip patch antenna, uses either a single blind via or an array of vias in the 3D-printed substrate. Two MPAs were fabricated on a 3D-printed substrate and it is shown that their fr values can be shifted upward or downward by following the proposed guidelines.

3D Printed Hemispherically Radiating Antenna for Broadband Millimeter Wave Applications
23 May 2023 Lukas Engel, Danti Khouri, Konstantin Lomakin, Andreas Hofmann, Micha Kleinlein, Ingrid Ullmann, Martin Vossiek, and Gerald Gold present a 3D printed monolithic antenna for millimeter wave-sensing applications with a full hemispherical coverage. The antenna is designed as an ensemble of a waveguide horn antenna and a differentially fed dipole antenna. The slotted waveguide approach was utilized to improve the manufacturing quality on the waveguide inside.
Reflectarray Feeds Augmented With Size-Reducing GRIN Lenses for Improved Power Handling and Aperture Efficiency
19 May 2023 Eric B. Whiting, Galestan Mackertich-Sengerdy, Ryan J. Chaky, Colin A. Mussman, Sawyer D. Campbell, Pingjuan L. Werner, and Douglas H. Werner demonstrate highly effective approaches for optimizing GRIN lenses to achieve different design objectives including high gain radiation with a compact feed as well as improved aperture efficiency and power handling. Additive manufacturing is employed to fabricate the lenses, and measured results agree well with simulations.
Analytic Approximation of In-Body Path Loss for Implanted Antennas
15 May 2023 Mingxiang Gao, Zvonimir Sipus, and Anja K. Skrivervik present a simplified model of an implanted antenna that provides closed-form approximate expressions to estimate EM radiation from the implant. In particular, they extend the expressions for the reactive near-field losses to both deep and shallow implants, by taking into account the implantation depth.n The proposed approximate method is verified by comparing the results obtained with the full-wave simulations in the case of a miniature implanted antenna, and with both simulated and measured results from two practical examples found in the literature.
3-D Printable Synthetic Metasurface to Realize 2-D Beam-Steering Antenna
10 May 2023 Foez Ahmed, Touseef Hayat, Muhammad U. Afzal, Shiyu Zhang, Karu P. Esselle, and William G. Whittow present highly radio-frequency (RF) transparent phase gradient synthetic metasurfaces made of sub-wavelength-sized 3D printable meta-atoms with tailored permittivity that cannot be achieved with off-the-shelf, commercially available materials. The synthesized meta-atoms design uses one dielectric block of PREPERM ® ABS 1000 material with air and metallic inclusions to make low- and high-permittivity materials. The inclusions’ size and height are varied to achieve a complete phase range from 0 to 360°, while maintaining transmission magnitudes greater than −3.0 dB.
A 3D-Printed Encapsulated Dual Wide-Band Dielectric Resonator Antenna With Beam Switching Capability
09 May 2023 Reza Shamsaee Malfajani, Hamed Niknam, Sampada Bodkhe, Daniel Therriault, Jean-Jacques Laurin, and Mohammad S. Sharawi present the concept of encapsulated dielectric resonator antennas (E-DRAs). In E-DRAs, smaller-sized DRAs with a specific permittivity is embedded inside a larger DRA with a lower permittivity allowing for simultaneous efficient radiation at two widely separated and widely covered frequency bands. The proposed E-DRAs cover both the sub-6-GHz band (with a large size DRA) and mm-wave band (with smaller sized DRAs) for 5G and beyond applications.
3-D Printed All-Dielectric GRIN Lens Antenna With an Integrated Feeder
05 May 2023 Anastasios Paraskevopoulos, Francesca Maggiorelli, Ilir Gas Hi, Cristian Della Giovampaola, Matteo Albani, Stefano Maci present the design, fabrication, and experimental verification of a new type of Graded-index (GRIN) lens antenna with an integrated feeder. The continuously varying refractive index distribution is chosen appropriately to offer the rays collimation at the lens aperture. It is practically implemented by varying the material density in a host medium, thus realizing a new type of all-dielectric high gain antenna, entirely using 3D printing. This solution can find application to high gain wireless communication and measurement systems.
Planar Array Subarray Division Method in Microwave Wireless Power Transmission Based on PSO&K-Means Algorithm
27 April 2023 Qian He Zhang and Zhao Yang Shen propose a clustering algorithm based on a combination of the particle swarm algorithm and the K-means algorithm for the subarray partitioning of planar arrays to address the problem of maximizing beam collection efficiency in microwave wireless power transmission. The effectiveness of the proposed method is evaluated by integrating the beam collection efficiency with parameters such as the receiving area and the size of the planar array.
Fully Printed 3-D Antennas With Wideband Radiation Isotropy Based on Annular Currents Models
02 May 2023 Ruiqi Wang, Kirill Klionovski and Atif Shamim propose a theoretical model based on annular ring currents to synthesize quasi-isotropic antenna radiation patterns. The theoretical model shows that wideband radiation isotropy can be achieved by optimizing the combination of azimuthal currents. We subsequently present spherical and cubical ESA designs that achieve measured wide impedance and radiation isotropy bandwidths exceeding 10% for the GSM900 band.
Circularly-Polarized Patch Antennas With Enhanced Bandwidth Based on Capacitively Coupled Orthogonal Patch Radiators
02 May 2023 Qiong-Sen Wu, Xiao-Yu Tang, Xiao Zhang, Lei Zhu, Gary Zhang and Chun-Bing Guo propose circularly-polarized (CP) patch antennas with enhanced bandwidth based on capacitively coupled orthogonal patch radiators Several patch radiators are alternately arranged one by one along the x - and y -direction, producing orthogonal currents and far fields. The adjacent patch radiators are coupled to each other and the coupling structure not only contributes to power distribution but also introduces 90° phase shift for circularly-polarized radiation.
A Concept of Advanced Design Governed by Theoretically Predicted Current Distributions on the Ground Plane Beneath an Aperture-Fed Microstrip Antenna
02 May 2023 Debi Dutta, Debatosh Guha and Chandrakanta Kumar explore a way of mitigating near field issues based on theoretical analysis and propose a simple strategic approach to reform the same for a rectangular patch. A representative design, theoretical justification, and experimental studies with an S-band prototype have been presented. XP suppression by 11dB has been experimentally achieved in the diagonal (D-) plane with no considerable changes in its H- or E-plane. That eventually attains an overall XP discrimination by nearly 27dB from the perspective of 3D radiation scenario.
Uniform Analysis of Multipath Components From Various Scenarios With Time-Domain Channel Sounding at 300GHz
02 May 2023 Johannes M. Eckhardt, Alper Schultze, Ramez Askar, Tobias Doeker, Michael Peter, Wilhelm Keusgen, and Thomas Kürner present a uniform and collaborative data evaluation of measurement sets from two different time-domain channel sounders. The channels show a great variety of characteristics depending on the scenario, the line-of-sight condition and the signal-to-noise ratio requirements of the prospective communication system. The extracted multipath components are published as research data for future analytical studies and simulations in relevant scenarios for the sixth generation of mobile systems.
Indirect Applications of Additive Manufacturing for Antennas
10 April 2023 Jonathan D. Lundquist, Lauren Linkous, Umar Hasni, and Erdem Topsakal report the fabrication methodology of stereolithography (SLA) printed molds for metal and resin cast antennas. In the first method, a conical horn created using metal cast molds printed from a glass-filled resin utilizes a casting technique allowing for low-cost 3D printing to fabricate metal antennas. The second casting method demonstrates the interchangeability between creating parts via SLA printing with a glass-filled resin and using the same resin cast into a reusable Polydimethylsiloxane (PDMS) mold.
3-D-Printed Spiral Leaky Wave Antenna With Circular Polarization
05 April 2023 Tomás Lira-Valdés, Eva Rajo-Iglesias, and Francisco Pizarro present the design, manufacturing and measurement of a fully dielectric leaky wave antenna operating at 18 GHz. The antenna is composed of a grounded dielectric substrate with a top dielectric Archimedean spiral corrugation, which allows obtaining a directive pencil-beam in broadside direction with circular polarization depending on the turning sense of the spiral.
Practical Correlation-Matrix Approaches for Standardized Testing of Wireless Devices in Reverberation Chambers
30 March 2023 Kate A. Remley, Sara Catteau, Ahmed Hussain, Carnot L. Nogueira, Mats Kristoffersen, John Kvarnstrand, Brett Horrocks, Jonas Fridén, Robert D. Horansky, and Dylan F. Williams extend the autocorrelation-based approaches currently used in standards to full correlation-matrix-based approaches in order to identify correlation between both spatially adjacent and non-adjacent samples in reverberation-chamber measurements. They employ a scalar metric that allows users to identify the number of effectively uncorrelated samples in new types of stirring sequences.
3-D Printed Dually Symmetric Orthomode Transducer and Horn Antenna at X-Band
03 April 2023 Ian Goode, and Carlos E. Saavedra present a dually symmetric orthomode transducer (OMT) and horn antenna for both single port linearly polarized operation and dual port circular polarization use. The feed uses two waveguide splitters and a feed bend to feed a four-port horn antenna that has the two groups of ports orthogonal to each other to produce a symmetric radiation pattern. The feed is printed from 316L stainless steel while the horn is printed from a plastic polymer and metallized using aluminum tape.
Systematic Design Method for Mutual Coupling Reduction in Closely Spaced Patch Antennas
28 March 2023 Hui Deng, Lei Zhu, and Zhao-An Ouyang present a systematic design approach to reduce the mutual coupling between a pair of closely spaced microstrip patch antennas (MPAs). This method can effectively overcome the main drawback of previous two-path cancellation methods, i.e., lack a systematic design guideline and heavily rely on the time-expensive trial-and-error procedure to mitigate mutual coupling in a best-effort manner. They propose the concept and workflow of the systematic design method, and introduce the circuit-level modeling upon the proposed two coupling routes.
Angle-Dependent Synthesis Method for Holographic Multi-Feed Antennas
27 March 2023 Thomas Frey, Maximilian Döring, Nico Riese, Christian Waldschmidt, and Tobias Chaloun present a novel synthesis method for holographic multi-feed antennas to combine all sub-holograms into an angle-dependent shared holographic aperture. In order to find the global error minimum between the shared holographic aperture and all ideal sub-holograms, a non-pixel-based genetic optimization is used. For a more accurately implementation of the analytical impedance tensor an eigenvector approach taking all tensor components into account is introduced.
Additive Manufacturing of Linear Continuous Permittivity Profiles and Their Application to Cylindrical Dielectric Resonator Antennas
16 March 2023 Simon P. Hehenberger, Stefano Caizzone, and Alexander G. Yarovoy consider the utilization of additive manufacturing (AM) to engineer the permittivity profile of dielectric resonator antennas (DRAs). The capabilities of AM are exploited to create continuously swept permittivity profiles and applied to cylindrical DRAs. The spatial variant lattices (SVL) synthesis algorithm is implemented to create the desired permittivity profiles from a single material, and resulting geometries are manufactured using a high-permittivity material in a fused deposition modeling AM process.
Additively-Manufactured All-Dielectric Microwave Polarization Converters Using Ceramic Stereolithography
15 March 2023 Steve M. Young, Mark Kauf, Jeffrey Kutsch, and Anthony Grbic report a class of all-dielectric, additively-manufactured polarization converters with tailored temporal frequency responses within the Ku and Ka microwave bands (15– 40 GHz). These multi-layer devices consist of cascaded, subwavelength, high-contrast gratings with different fill fractions and orientations, providing control over the effective anisotropic properties of each layer. Three example devices based on alumina/air gratings have been monolithically fabricated using ceramic stereolithography: a broadband reflective half-wave plate, a broadband isotropic polarization rotator, and a dual-band linear-to-circular polarization converter.
Highly Efficient Calibration of Antenna Arrays by Active Targets in the Near-Field
08 March 2023 Matthias Linder, Benedikt Meinecke, Enes Halici, Dominik Schwarz, and Christian Waldschmidt propose a calibration setup employing active calibration targets (ACT) to reduce the calibration effort, hereby defined as the number of required measurements. The setup allows the storage of a multitude of data points within a single measurement. It is placed in the near-field of the array to relax the requirements on the size of the anechoic chamber. Employing multiple targets makes it challenging to compensate for the near-field effects.