A new electrically small antenna for on-demand 3.6/5.8 GHz wireless applications

This article presents a highly miniaturized dual-band electrically small antenna (ESA) for on-demand 3.6 and 5.8 GHz wireless applications. A partial rectangle-shaped structure is printed on the back face of the dielectric material, forming the antenna's ground (GND) plane. The radiating structure of the antenna consists of a C-shaped structure and a U-shaped ring connected to it, which is printed on the dielectric material's front face. The overall dimensions of the designed antenna are 0.160λo × 0.160λo × 0.02λo at the lowest operating frequency. The proposed antenna has a ka value of 0.56 at the lowest operating frequency, which is 3.59 GHz. Thus, the proposed antenna is considered as electrically small. The characteristic mode analysis is adopted to provide a clear understanding of the antenna's resonance behavior. The antenna has been fabricated and the simulation results were validated through measurements. Good agreement between simulated and measured results was obtained. Dual-band operation at 3.62 and 5.75 GHz was achieved, according to the measured reflection coefficient. The proposed antenna offers an adequate performance in terms of gain and efficiency, based on simulation and measurement results. Because of these characteristics, the antenna is well-suited to new wireless applications.

Innovative Design and Analysis of an Electrically Small Reconfigurable Antenna for GPS and Blue Tooth Applications

In this paper, an electrically small, planar antenna with broad side radiation pattern is presented. The design contains a dipole and a segmented circular loop which works equivalent to that of a magnetic dipole. A circular patch with slots is used to provide impedance matching. In general, electrically small antennas suffer from narrow bandwidth. In this paper, the reconfigurability of the small antenna for two different applications, 1.5GHz and 2.4GHz, is discussed. This reconfigurability was achieved by using a BAR 64-03W pin diode to adjust the resonant frequency. Two reconfigurable frequency bands were achieved at 1.5GHz and 2.4GHz with broad side radiation patterns.

Small Antenna Design of Triple Band for WIFI 6E and WLAN Applications in the Narrow Border Laptop Computer

This paper presents the design of a small antenna for use in a wireless local area network (WLAN) and Wi-fi 6E on a narrow-border laptop. The dimensions of the antenna are 43 × 3 × 0.4 mm3, and it features a grounding system simulated by a 200 × 260 mm2 copper plate. At low-frequency bands, a couple-fed right arm can excite the fundamental at 2.45 GHz in the λ/4 resonant mode to cover the range of 2.4–2.848 GHz. At higher bands, the couple-fed left arm and direct-fed right arm can control the higher 3λ/4 mode at 5.825 GHz and 5λ/4 mode at 6.85 GHz. The direct-fed left arm excites the fundamental at 5.16 GHz in the λ/4 resonant mode and, with integration of 5.16, 5.825, and 6.85 GHz, can fully cover the range of 5.15–7.125 GHz. In far-field measurements, the peak gain and efficiency in a WLAN with Wi-Fi 6E were 0.82 and 2.58 dBi and 53% and 68% in the low and high bands, respectively. Overall, the experiments revealed that the antenna exhibits a sufficient level of performance for a narrow-border laptop.

A Convex Optimization Approach for the Design of Supergain Electrically Small Antenna and Rectenna Arrays Comprising Parasitic Reactively Loaded Elements

<div><div><div><p>A convex optimization formulation is provided for antenna arrays comprising reactively loaded parasitic elements. The objective function consists of maximizing the array gain, while constraints on the admittance are provided in order to properly account for reactive loads. Topologies with two and three electrically small dipole arrays comprising one fed element and one or two parasitic elements respectively are considered and the conditions for obtaining supergain are investigated. The admittance constraints are formulated as linear constraints for specific cases as well as more general, quadratic constraints, which lead to the solution of an equivalent convex relaxation formulation. A design example for an electrically small superdirective rectenna is provided where an upper bound for the rectifier efficiency is simulated.</p></div></div></div>

A Convex Optimization Approach for the Design of Supergain Electrically Small Antenna and Rectenna Arrays Comprising Parasitic Reactively Loaded Elements

<div><div><div><p>A convex optimization formulation is provided for antenna arrays comprising reactively loaded parasitic elements. The objective function consists of maximizing the array gain, while constraints on the admittance are provided in order to properly account for reactive loads. Topologies with two and three electrically small dipole arrays comprising one fed element and one or two parasitic elements respectively are considered and the conditions for obtaining supergain are investigated. The admittance constraints are formulated as linear constraints for specific cases as well as more general, quadratic constraints, which lead to the solution of an equivalent convex relaxation formulation. A design example for an electrically small superdirective rectenna is provided where an upper bound for the rectifier efficiency is simulated.</p></div></div></div>

Intraflagellar Transport Proteins as Regulators of Primary Cilia Length

Primary cilia are small, antenna-like organelles that detect and transduce chemical and mechanical cues in the extracellular environment, regulating cell behavior and, in turn, tissue development and homeostasis. Primary cilia are assembled via intraflagellar transport (IFT), which traffics protein cargo bidirectionally along a microtubular axoneme. Ranging from 1 to 10 μm long, these organelles typically reach a characteristic length dependent on cell type, likely for optimum fulfillment of their specific roles. The importance of an optimal cilia length is underscored by the findings that perturbation of cilia length can be observed in a number of cilia-related diseases. Thus, elucidating mechanisms of cilia length regulation is important for understanding the pathobiology of ciliary diseases. Since cilia assembly/disassembly regulate cilia length, we review the roles of IFT in processes that affect cilia assembly/disassembly, including ciliary transport of structural and membrane proteins, ectocytosis, and tubulin posttranslational modification. Additionally, since the environment of a cell influences cilia length, we also review the various stimuli encountered by renal epithelia in healthy and diseased states that alter cilia length and IFT.

Metamaterial-inspired electrically small antenna for microwave applications

Electrically small antennas are becoming more important to compete with the rising modern civilization. Hence, this study presents a new approach of electrically small antenna inspired by a metamaterial structure which creates an impact by achieving a multi-band property that can be applied for different microwave applications. A high-frequency electromagnetic simulator was utilized to design, simulate, and analyze the antenna performance. About 58% reduction was achieved due to the incorporation of the modified electric field-driven capacitor-driven metamaterial. The initial length of the antenna was 0.61λ0 × 0.58λ0 × 0.12λ0; however, after embedding metamaterial, 58% reduction was achieved and the size of the electrical length of the reduced antenna becomes 0.254λ0 × 0.207λ0 × 0.013λ0, where λ0 denotes free-space wavelength. The electrical limitation factor (ka) of the antenna that was 0.94 (below 1) satisfied the conditions of electrically small antenna. The antenna achieved the highest measured gain of 4.79 dB. Due to its compact miniaturized size and resonance characteristics, the proposed antenna is compatible for broad spectrum of applications in the field of microwave communication.