Showing papers in "IEEE Antennas and Propagation Magazine in 2019"
TL;DR: Practical guidelines for designing wearable antennas pay particular attention to low-cost and time-saving fabrication techniques that distinguish between nontextile and fully textile antennas.
Abstract: This article provides a few practical guidelines for designing wearable antennas. A crucial requirement for this kind of antenna is to be noninvasive and "invisible" to the final user. To this end, an application-centered approach is required for both the design and the fabrication process, which leads to high cost, thereby limiting the large-scale production of wearable antennas. Accordingly, this article pays particular attention to low-cost and time-saving fabrication techniques that distinguish between nontextile and fully textile antennas.
70 citations
TL;DR: In the past five years, technologists at NASA's Jet Propulsion Laboratory (JPL) have designed, tested, and successfully flown these innovative and enabling small-satellite antennas as discussed by the authors.
Abstract: Small satellites (smallsats) provide low-cost access to space and have historically been used for flight technology demonstrations and limited-function space science activities. Novel antenna technologies have enabled high-performance smallsat telecommunications, science in Earth orbit, and the first CubeSat mission to deep space. In the past five years, technologists at NASA's Jet Propulsion Laboratory (JPL) have designed, tested, and successfully flown these innovative and enabling smallsat antennas. This article describes these innovations and their impact on smallsat performance for recent and future NASA missions.
62 citations
TL;DR: In this paper, a two-layer metasurface based on frequency-selective surfaces (FSSs) backed by a thin-grounded dielectric substrate is presented.
Abstract: In this article, a wideband metasurface for radar cross-section (RCS) reduction based on a polarization conversion is presented. The unit cell is composed of a two-layer metasurface based on frequency-selective surfaces (FSSs) backed by a thin-grounded dielectric substrate. The metasurface is able to rotate the polarization by 90d using special binary elements "0" and "1" in combination. The elements are arranged using a binary coding matrix formed by a group search optimization (GSO) algorithm. The optimized arrangement resulted in the distribution of scattered electromagnetic (EM) waves and suppression of the maximum bistatic RCS of the metasurface over a broadband of incident angles for both polarizations. Additionally, a polarization conversion ratio (PCR) of nearly 131% with an efficiency higher than 90% is achieved. The reflective two-layer metasurface is designed in such a way to generate a reflection phase difference of 180d between elements 0 and 1 on a broad frequency band. A theoretical analysis is performed on the ratio of the 0 and 1 elements using the least square error (LSE) method to find the best ratio value. The simulated and experimental results show that the structure can significantly reduce the RCS by 10 dB over a wide frequency range from 5.1 to 22.1 GHz (125%) at the normal incidence for both polarizations.
61 citations
TL;DR: The results confirm the potential for ZnO-based TCOs as suitable alternatives to indium tin oxide (ITO) for microwave applications, and mainly on doped zinc oxide (ZnO), as promising material for transparent antennas and filters.
Abstract: This article discusses challenges in designing optically transparent antennas and filters for smart city applications. The smart city concept seeks to alleviate urban challenges that include infrastructure and network capacity. The proposed frequencies for the next generation of wireless networks (5G) would result in shorter broadcast distances and network dead zones. Additional access points and signal repeaters embedded into the existing infrastructure, by inserting transparent antennas into windows via either meshed conductors or transparent conductive oxides (TCOs), would help to mitigate these issues. Glass-embedded frequency-selective surfaces (FSSs) can be used anywhere that requires microwave filtering and optical transparency. The cyberphysical system security in this forthcoming network also poses challenges to entities that require strict network security. This article focuses mainly on TCOs, particularly doped zinc oxide (ZnO), as promising material for transparent antennas and filters. To demonstrate the potential of ZnOs as highly transparent conductive materials for antenna and filter applications, we designed, fabricated, and tested a gallium-doped ZnO- (GZO) based optically transparent 2.4-GHz Wi-Fi antenna and two FSSs (bandpass and bandstop filters) operating in the 23-29-GHz frequency range. These results confirm the potential for ZnO-based TCOs as suitable alternatives to indium tin oxide (ITO) for microwave applications.
53 citations
TL;DR: In this article, different techniques for transmitting a high-information-rate signal using a narrow-band (high-Q-factor) antenna are presented from an energy balance and thermodynamic point of view.
Abstract: The fundamental limits of antennas tie its electrical size to its quality factor (Q-factor) and radiation efficiency. The Q-factor is linearly proportional to the inverse of the instantaneous bandwidth for a narrow-band antenna. However, the thermodynamic definition of the Q-factor is equal to the ratio of stored energy to the dissipated power per cycle multiplied by 2p. In this definition, the frequency and type of stored energy are not considered; therefore, one can transmit information by modulating the frequency and/or type of stored energy, while maintaining the total stored energy with a rate higher than that which is restricted by fundamental limits. In this article, we show that instantaneous bandwidth does not necessarily define the maximum information rate of an antenna. Different techniques for transmitting a high-information-rate signal using a narrow-band (high-Qfactor) antenna are presented from an energy balance and thermodynamic point of view. A few examples are presented as proof of concept. To help with understanding this concept, we have applied some of the proposed modulation schemes to a pendulum system as a second-order mechanical resonator. Finally, the proposed modulation techniques are confirmed using simulations.
34 citations
TL;DR: In this article, a wide-scan and broadband focal plane array (FPA) concept is introduced, which provides high antenna gain and effective isotropic radiated power (EIRP) with electronic beamsteering within a relatively large field of view (FoV), up to +/- 20°.
Abstract: A wide-scan and broadband focal-plane array (FPA) concept is introduced in this article, which provides high antenna gain and effective isotropic radiated power (EIRP) with electronic beamsteering within a relatively large field of view (FoV), up to +/-20°. The antenna uses a bifocal double-reflector concept that optimizes the illumination of the focal-plane region. In this way, we have reduced the required size of the feed array and have maximized the number of simultaneously active array elements. By using a photonics beamformer, a broadband system for the 20-40-GHz band can be created with a fiber-based interface to a central processing unit. This hybrid antenna system is a very interesting concept for future 5G and beyond [5G millimeter-wave (mm-wave) base stations, two-way satellite communication systems, and point-to-point wireless backhaul systems]. A silicon BiCMOS low-noise amplifier (LNA) and a photonic integrated circuit (PIC) for the optical beamformer have been developed and integrated into the overall system. A system-level demonstrator was developed and experimentally validated in receive mode. Our concept provides an antenna gain of more than 40 dBi over an FoV of +/-15° at 28.5 GHz.
33 citations
TL;DR: Results show that optimized planar meander line antennas meet the lower bound on the radiation quality factor (Q-factor) (maximizing single-resonance fractional bandwidth) but are far from reaching the associated physical bounds for efficiency.
Abstract: Considerable time is often spent optimizing antennas to meet specific design metrics. Rarely, however, are the resulting antenna designs compared to rigorous physical bounds on those metrics. Here, we study the performance of optimized planar meander line antennas with respect to such bounds. Results show that these simple structures meet the lower bound on the radiation quality factor (Q-factor) (maximizing single-resonance fractional bandwidth) but are far from reaching the associated physical bounds for efficiency. The relative performance of other canonical antenna designs is comparable in similar ways, and the quantitative results are connected to intuitions from small antenna design, physical bounds, and matching network design.
32 citations
TL;DR: A robust attempt at such an evaluation is overdue becauseAntenna designers, often not fully schooled in optimization, can be confused as to which algorithm in which software package should be used.
Abstract: Numerous software packages exist for solving antenna design optimization problems, with many of these employing a variety of approaches, leading, in turn, to variations in optimization performance. Antenna designers, often not fully schooled in optimization, can be confused as to which algorithm in which software package should be used. A wrong choice can cause the failure of the optimization or the expending of considerable time on the computationally expensive 3D electromagnetic (EM) simulations involved. While it is true that the various algorithms, combined with the variety of complex challenges found in different real-world scenarios make a direct comparison among tools difficult, a robust attempt at such an evaluation is overdue.
32 citations
TL;DR: In this article, a dual-mode wideband circularly polarized (CP) DRA is implemented by using a stair-shaped microstrip feed line, a pair of L-shaped slots in the ground plane, and a rectangular DR.
Abstract: An examination of a new kind of rectangular dielectric resonator antenna (DRA) demonstrates that it delivers better gain and radiation efficiency for operating in the Worldwide Interoperability for Microwave Access (Wi-MAX) (3.3-3.7 GHz) band. The new dual-mode wideband circularly polarized (CP) DRA is implemented by using a stair-shaped microstrip feed line, a pair of L-shaped slots in the ground plane, and a rectangular DR.
30 citations
TL;DR: In this paper, the authors categorized existing dual-polarization antennas into three separate groups according to their topologies and discussed various cross-coupling mechanisms between orthogonal polarizations.
Abstract: Existing dual-polarization antennas are categorized into three separate groups according to their topologies. Various cross-coupling mechanisms between orthogonal polarizations are specifically discussed in three categories and related to port isolation and cross-polarization radiation. Some representative antennas of each group are presented, and their performance is compared in terms of port isolation, cross polarization, frequency bandwidth (BW), dimension, and complexity. The techniques to enhance the polarization purity is discussed in the context of example antennas. Finally, further research opportunities in each category are introduced.
30 citations
TL;DR: Reflectarray antennas are proposed as an attractive solution for the design of novel MBA configurations to produce multispot coverage, with a smaller number of apertures than conventional MBA systems based on reflector technology.
Abstract: This article presents some recent developments in multiplebeam antennas (MBAs) based on reflectarrays for communication satellites in the Kurz (K) and Kurz-above (Ka) bands. The existing high-throughput satellites commonly employ four reflector antennas to provide cellular coverage that is formed by multiple spot beams in a four-color scheme. Reflectarray antennas are proposed as an attractive solution for the design of novel MBA configurations to produce multispot coverage, with a smaller number of apertures than conventional MBA systems based on reflector technology. Single and dual reflectarray configurations have been considered for the purpose of exploiting their ability to produce independent beams in different polarizations and frequencies.
TL;DR: In this article, the authors present a comprehensive literature study that examines the advantages and limitations of using magnetodielectric materials and propose a step-by-step simulation procedure for the development of reconfigurable antennas using magnetic materials.
Abstract: The growing demand for low-profile, efficient compact antennas with reconfigurable characteristics has prompted antenna engineers to use novel materials in place of conventional dielectrics. Magnetodielectric materials combining both dielectric and magnetic properties have been widely investigated. In this article, we present a comprehensive literature study that examines the advantages and limitations of using these materials. We focus primarily on magnetodielectric materials exhibiting anisotropic behavior and tunable permeability by means of physical mechanisms (e.g., by applying an external magnetic field). This article provides theoretical background, modeling guidelines, and a step-by-step simulation procedure, and aims to be a straightforward and useful guide for the development of reconfigurable antennas using magnetic materials. We explain the reasons for selecting ferrimagnetic oxides for antenna applications and discuss their fundamental properties. The critical parameters that should be taken into consideration for the determination of the permeability of ferrimagnetic oxides in various magnetization states are reported. To demonstrate the proper use of this analysis, we have designed, simulated, and implemented a reconfigurable ferrite antenna prototype. The proposed simulated procedure is validated via measurements.
TL;DR: In this paper, various fractal geometries have been introduced for antenna applications, and the main objective of fractal applications is to reduce the size of the antenna for wideband characteristics, while maintaining other design parameters at an acceptable level.
Abstract: Until the 1980s, shielded dielectric resonators (DRs) were used as high-quality factor energy storage devices for filter and oscillator applications [1]. Later, they gained status as effective radiators due to the efforts of Long, McAllister, and Chen [2]. Since then, enormous DR antenna (DRA) designs have been explored and different feeding techniques introduced to achieve optimum antenna characteristics like high gain and low quality factor (Q-factor), etc. Compared to microstrip antennas, DRAs offer attractive features such as low loss, high efficiency, and wide impedance bandwidth (BW). Low-profile design and BW enhancement are two important aspects of effective antenna synthesis. Various BW enhancement techniques-like the compact slot DRA [3], aperture feeding, perturbation, cavity-backed disk, ring-shaped DRA, and the stacking of two or more dielectric layers [4]-can be applied on DRAs for this purpose. The stacked DRA, dual-segment, hybrid DRA, and slots in ground-plane approaches were also well suited to improve the impedance BW of DRA [5]-[10]. Various multilayer cylindrical DRA (MCDRA) structures have been proposed and investigated for BW enhancement like the stacked cylinder approach [11], [12], slotted coaxial layered structure [13], etc. More recently, various fractal geometries have been introduced for antenna applications. The main objective of fractal applications is to reduce the size of the antenna for wideband characteristics, while maintaining other design parameters at an acceptable level. Several antenna configurations based on fractal geometries have been previously examined [14].
TL;DR: In this paper, a circular microstrip patch is loaded with a metamaterial structure using a complementary split ring resonator (CSRR) with partially loaded nonuniform metasurfaces (NUMSs) on a ground plane.
Abstract: A smaller microstrip antenna design is essential for current and future wireless applications. For the design proposed in this article, researchers achieved size reduction when a circular microstrip patch is loaded with a metamaterial structure using a complementary split ring resonator (CSRR) with partially loaded nonuniform metasurfaces (NUMSs) on a ground plane. The designed antenna achieved a size reduction of 74% compared to a conventional microstrip antenna. The proposed antenna, resonating at 6.22 GHz, is designed, fabricated, and tested, and the measured results are then compared with the simulations as well as with the designs reported in the literature. The proposed antenna can be used for wireless applications, such as an indoor base-station antenna for vehicle-tovehicle communications.
TL;DR: This article aims to fill the void with a general description of early efforts that drove the development of AiP technology as the authors know it today.
Abstract: A ntenna-in-package (AiP) technology integrates an antenna or antennas with a radio or radar transceiver die (or dies) into a standard surface-mount package. AiP technology balances performance, size, and cost well. Thus, it has been widely adopted by chipmakers for radios and radars. Many papers and patents are devoted to AiP technology. However, little is known about the history of this important antenna and packaging technology. This article aims to fill this void with a general description of early efforts that drove the development of AiP technology as we know it today.
TL;DR: In this article, the authors performed the characteristic mode analysis (CMA) of general metallic-dielectric structures using the volume-surface integral equation (VSIE) and proved that only the substructure operator is symmetrical and therefore fulfills CMA's theoretic requirements.
Abstract: In this article, the characteristic mode analysis (CMA) of general metallic-dielectric structures is performed using the volume-surface integral equation (VSIE). The whole-structure and substructure formulations for the CMA are presented and discussed. It is proven that only the substructure operator is symmetrical and therefore fulfills CMA's theoretic requirements. Such a symmetrical operator ensures that the computed eigencurrents are orthogonal and the eigenvalues are real numbers. Numerical analysis verifies that the substructure formulation yields more accurate results than the whole-structure one. A smartphone chassis on an FR-4 substrate and a split-ring resonator (SRR) on a Teflon substrate are analyzed using the presented method. The influence of the mesh size is discussed and it is shown that the volume mesh density increases at a rate similar to the surface mesh. In short, the volume-surface integral formulation with a substructure treatment is versatile, stable, and reasonably efficient for the CMA of thin metallicdielectric structures with planar or curved shapes.
TL;DR: A circular conformal array antenna with beamsteering capabilities as well as omnidirectional performance at 3.5 GHz (S-band) with novel tunable T-junctions based on p-i-n diodes in microstrip technology is presented.
Abstract: A circular conformal array antenna (CAA) with beamsteering capabilities as well as omnidirectional performance at 3.5 GHz (S-band) is presented. The single radiating elements are formed by double-stacked microstrip patches placed on the planar faces of an octagonal holding structure fabricated with a 3D printer. An eight-way tunable feeding network (TFN) is designed, manufactured, and integrated into the conformal structure to excite the array elements. Novel tunable T-junctions (TTs) based on p-i-n diodes are proposed to form the TFN in microstrip technology. This novel T-junction allows a splitting configuration with uniform distribution to the two output ports or a switching mode to deliver the signal to either output port. In all T-junction operation modes, good input matching performance is achieved. The TFN network is integrated into the conformal antenna and digitally controlled by a microcontroller Arduino MEGA. A total of 29 states grouped in six modes with a global matching bandwidth of 17.2% can be selected. The omnidirectional radiation and beamsteered directional patterns (covering 360°) can be electronically tuned. The proposed antenna is suitable for future 5G terrestrial communications in the 3.5-GHz International Mobile Telecommunication (IMT) range, the primary candidate band for the first 5G networks.
TL;DR: Four examples are used to illustrate the nature and modeling of multiphysics problems related to electromagnetic (EM) hyperthermia for cancer treatment, which requires solving EM and bioheat transfer equations for the planning and optimization of the treatment process.
Abstract: As computational methods for solving Maxwell's equations mature, we can now start to tackle much more challenging multiphysics problems that have numerous applications in science and technology fields. In this article, we use four examples to illustrate the nature and modeling of multiphysics problems. The first example is related to electromagnetic (EM) hyperthermia for cancer treatment, which requires solving EM and bioheat transfer equations for the planning and optimization of the treatment process. The second example concerns the heat problem in integrated circuits (ICs) due to EM dissipated power, its effects, and a potential cooling solution, which requires an electrical-thermal-fluid-mechanical cosimulation. The third example considers modeling of monolithic microwave ICs (MMICs), which consist of both distributive and lumped circuit components. The fourth example simulates the air and dielectric breakdown in high-power microwave devices by coupling EM modeling with various plasma models. With these examples, we detail some of the technical challenges typically encountered in multiphysics modeling and their potential solutions.
TL;DR: A novel planar chipless radiofrequency identification (RFID) tag composed of multiple miniaturized reflecting resonators based on a slowwave structure that offers a good miniaturization ratio and spectral coding efficiency and demonstrates the efficiency of the used approach to develop high-performance chipless tags.
Abstract: In this article, we introduce a novel planar chipless radiofrequency identification (RFID) tag. The tag is composed of multiple miniaturized reflecting resonators based on a slowwave structure. To validate the proposed approach, a tag with a coding capacity of 16 b was designed with a compact size of 15 t 21mm2. Tags with different pattern configurations were fabricated using a Rogers RO4003 substrate, and their radar cross-section (RCS) responses were measured. Compared to conventional multiresonator tags, the proposed tag offers a good miniaturization ratio and spectral coding efficiency. In addition, the measurements revealed a high quality factor (Q-factor) and coding robustness, which demonstrates the efficiency of the used approach to develop high-performance chipless tags.
TL;DR: In this article, a tapered-slit octagonal-shaped patch radiator was implemented to realize the CRLH microstrip antenna with wide-angle radiation using a proximity-coupled feed.
Abstract: A tapered-slit-patch antenna with wide-angle circularly polarized (CP) radiation and a compact rectifier was investigated for energy-harvesting systems. A tapered-slit octagonal-shaped patch radiator was implemented to realize the CP microstrip antenna with wide-angle radiation using a proximity-coupled feed. Eight tapered slits with length difference of 1.3% were embedded along the octagonal directions symmetrically on the microstrip radiator from the patch's center. The antenna prototype showed a gain of more than 5.8 dBic across the CP bandwidth of 7 MHz (894-901 MHz) with a 3-dB axial ratio (AR) beamwidth of more than 180°. A compact composite right/left-handed (CRLH)-based rectifier operating at 900 MHz was designed to be used along with the antenna for radio-frequency (RF) energy-harvesting system. A microstrip line forms the righthanded part of the CRLH transmission line (TL), and the lumped components form the left-handed part of the CRLH TL. The proposed rectifier was compact with size of 0.18λ
0
× 0.075λ
0
× 0.0002λ
0
at 900 MHz with a high RF-dc conversion efficiency of 43%.
TL;DR: The development of horn antennas is described from their inception in the 1890s to the present as mentioned in this paper, and the advancement of their fundamental features, which are often driven by applications, is described.
Abstract: The development of horn antennas is described from their inception in the 1890s to the present. Our main objective is to describe the advancement of their fundamental features, which are often driven by applications. The horn antennas discussed here were selected based on their significant concept advancements and are listed in chronological order within each class based on their first publication. Until the 1960s, only metal horns were used. In the 1970s, horns with dielectric loading were developed and resulted in several new and advanced horn designs. The latest renaissance in horn technology was fueled by the advent of metamaterials over the last 15 years, enabling horns with metasurfaces (metahorns) and horns with metalenses in particular. We now have air-filled, dielectric-loaded, and metamaterial-loaded horns; from inception, we have seen the transformation from metal horns to metahorns. More details will be supplied in the following sections.
TL;DR: In this paper, an inkjet-printed tree-shaped fractal antenna (FA) with a small metal footprint is presented along with its method of fabrication on a flexible substrate, and their characteristics were measured.
Abstract: In this article, an inkjet-printed tree-shaped fractal antenna (FA) with a small metal footprint is presented along with its method of fabrication on a flexible substrate. The antenna includes a tree-shaped fractal part, a tapered matching line, and a coplanar waveguide (CPW) line with filleted grounds. The fractal tree is formed by repeating a scaled V-shaped unit cell in each iteration. As the fractal iterations of the antenna are increased, the resonance frequency of the antenna shifts in a large range of frequencies while its radiation properties, dimension, and metal footprint remain almost constant. Six different versions of the proposed FA were fabricated by an inkjet printer on a flexible substrate, and their characteristics were measured. Simulation and measurement results showed that a 16% increase in the antenna's metal footprint shifts the resonance frequency from 16.38 GHz to 5.08 GHz. The shift of 3.22 times of the resonance frequency after four iterations is 61% higher than the state of the art of tree-shaped FAs in the literature. The proposed FA provides a 1.36-GHz bandwidth (BW) and a torus-shaped far-field radiation pattern with a 92d half-power beamwidth (HPBW) in the azimuth direction at 5.08 GHz, whereas the wavelength-normalized metal footprint is 87% smaller than a rectangular patch antenna and at least 60% smaller than other similar FAs. The area of the proposed antenna is more than 3.54 times smaller than similar FAs in the literature. The proposed flexible FA weighs about 2.08 g, of which 1.54 g is the weight of its SMA coaxial connector. The antenna thickness is 130 mm. The lightweight construction and low profile of the miniaturized antenna make it a good candidate for spaceborne and wearable applications.
TL;DR: The article presents the design of a Ka-band synthetic aperture radar (SAR) instrument based on innovative phased-array antennas, with steering capability in azimuth and elevation, with a marginal reduction in performance compared to conventional phasedarray solutions previously developed for SAR instruments.
Abstract: The article presents the design of a Ka-band synthetic aperture radar (SAR) instrument based on innovative phased-array antennas, with steering capability in azimuth and elevation. To limit the complexity and costs associated with conventional large active arrays with regular layouts, a sparse array concept is presented. The proposed approach results in a 40% reduction in the number of active controls, with a marginal reduction in performance compared to conventional phasedarray solutions previously developed for SAR instruments. Additionally, a preliminary thermomechanical design is presented to assess the challenges associated with the industrial production and to identify options for accommodation on the spacecraft.
TL;DR: In this article, the authors proposed two new frequency-selective surface (FSS) designs based on specific combinations of a multiple number of semicircles, which were simulated with commercial electromagnetic simulation software.
Abstract: This article proposes two new frequency-selective surface (FSS) designs based on specific combinations of a multiple number of semicircles. One of the proposed designs makes use of four semicircles, yielding a single-band frequency response. The other consists of a combination of eight semicircles arranged in a square-like shape, producing a dual-band frequency response. The proposed designs were simulated with commercial electromagnetic simulation software.
TL;DR: In this article, the authors compared the performance of microstrip and substrate integrated waveguide (SIW) technologies in terms of dielectric loss and directivity performance in a two-level corporate feeding network.
Abstract: Several low-cost feeding network configurations have been tested for an antenna array eligible for a 5G communication environment. Microstrip and substrate integrated waveguide (SIW) technologies have been evaluated in the feeding network and compared in terms of dielectric loss and directivity performance. Although microstrip dielectric loss is lower, a higher gain value is obtained with an SIW feeding network due to the directivity maximization. Three gain values have been implemented with different array sizes of 4 × 4, 8 × 8, and 16 × 16 radiating elements with a two-level corporate feeding network (CFN) in SIW and microstrip technologies. Measured matching bandwidth under -10 dB more than 20%, whereas the -1-dB gain bandwidth is 6%.
TL;DR: In this article, a Truncated-corner probe-fed (TCPF) antenna with a very low axial ratio (AR) was used to provide approximately 0.3% CP bandwidth (AR l 3 dB along with S11 l-10 dB).
Abstract: Truncated-corner probe-fed (TCPF) patches are popular for their simple design that provides circularly polarized (CP) radiation with a very low axial ratio (AR). For a thin substrate (s 0.026lg), this antenna provides approximately 0.3% CP bandwidth (BW) (AR l 3 dB along with S11 l-10 dB). However, as the substrate thickness is increased for enhancing the matching BW, an offset among the frequencies featured with minimum AR and optimum S11 is observed. This degrades the effective BW, with an overlapping of both S11 l-10 dB and AR l 3 dB.
TL;DR: A new methodology based on the GO and DE is presented and shown to achieve accurate results when compared with real measurements, providing a computational time reduction of up to 90% compared to the conventional approach using GO with the UTD and DE.
Abstract: In this article, we compare deterministic methodologies for characterizing channel behavior in heterogeneous and composite scenarios. These techniques include one that combines a 3D ray launching (RL) approach based on geometrical optics (GO), a second based on GO and the uniform theory of diffraction (UTD), and another that includes a diffusion equation (DE) method based on the equation of transfer. A new methodology based on the GO and DE is presented and shown to achieve accurate results when compared with real measurements. The proposed technique provides a computational time reduction of up to 90% compared to the conventional approach using GO with the UTD and DE.
TL;DR: In this paper, the impact of mutual coupling on the far-field peak sidelobe performance of a finite planar phased-array antenna having a circular aperture shape and containing 2,066 elements arranged in a triangular grid was investigated.
Abstract: This article will deal with the impact of mutual coupling on the far-field peak sidelobe performance of a finite planar phased-array antenna having a circular aperture shape and containing 2,066 elements arranged in a triangular grid. The radiator that is used is of the open-ended rectangular waveguide type, vertically polarized. The computation of the far-field performance of the array antenna is based on the use of embedded element patterns (EEPs). The effect of mutual coupling on the EEPs is taken into account through measured coupling coefficients.
TL;DR: In this article, the authors describe the different antenna designs developed at MDA using the DFMAIT approach and presents automated test and integration setups developed for higher-volume production, such as steerable antenna designs, fastener-free feedchains, 3D-printed antennas as well as automated assembly and test setups.
Abstract: The commercial satellite industry, which has primarily been focused on highly customized geostationary satellites, is seeing increasing interest in constellations of small satellites (smallsats) operating in nongeostationary orbits. These smallsat constellations require larger quantities of antennas that are cost-/mass-effective and compact. Ideally, this is achieved by designing for manufacturing, assembly, integration, and test (DFMAIT). Maxar Technologies Company (MDA), a global leader in antenna systems, developed its expertise through R&D, establishing itself as a key supplier for antennas on constellations such as Iridium-NEXT, O3b, and OneWeb. These capabilities range from innovative steerable antenna designs, fastener-free feedchains, 3D-printed antennas as well as automated assembly and test setups. MDA is also leveraging this acquired knowledge to develop new products for future geostationary missions. This article describes the different antenna designs developed at MDA using the DFMAIT approach and presents automated test and integration setups developed for higher-volume production.
TL;DR: The quest for more competitive space segment cost to maintain an attractive commercial proposition of satellite communication services has never been as noticeable as it is today because the end user is becoming more technology agnostic with a large and diverse range of services from which to choose.
Abstract: The quest for more competitive space segment cost to maintain an attractive commercial proposition of satellite communication services has never been as noticeable as it is today. This is mainly because the end user is becoming more technology agnostic with a large and diverse range of services from which to choose.