Tailorable optical scattering properties of the V-shaped plasmonic nano-antennas: a computationally efficient and fast analysis

We introduce an efficient computational scheme based on Macro Basis Function (MBF) method, to analyze the scattering of a plane wave by the V-shaped plasmonic optical nano-antennas. The polarization currents and the scattered fields for symmetric and anti-symmetric excitations are investigated. We investigate how the resonant frequency of the plasmonic V-shaped nanoantenna is tailored by engineering the geometrical parameters and by changing the polarization state of the incident plane wave. The computational model presented herein is faster by orders of magnitude than commercially available finite methods and is capable to characterize also other nanoantennas comprising of junctions and bends of nanorods.Comment: Final version published in JOSA A (6 pages, 9 figures). Work sponsored by DARPA/MTO Young Faculty Award #N66001-11-1-414

Eight-Element Compact UWB-MIMO/Diversity Antenna with WLAN Band Rejection for 3G/4G/5G Communications

An eight element, compact Ultra Wideband-Multiple Input Multiple Output (UWB-MIMO) antenna capable of providing high data rates for future Fifth Generation (5G) terminal equipments along with the provision of necessary bandwidth for Third Generation (3G) and Fourth Generation (4G) communications that accomplishes band rejection from 4.85 to 6.35 GHz by deploying a Inductor Capacitor (LC) stub on the ground plane is presented. The incorporated stub also provides flexibility to reject any selected band as well as bandwidth control. The orthogonal placement of the printed monopoles permits polarization diversity and provides high isolation. In the proposed eight element UWB-MIMO/diversity antenna, monopole pair 3-4 are 180o mirrored transform of monopole pair 1-2 which lie on the opposite corners of a planar 50 x 50 mm2 substrate. Four additional monopoles are then placed perpendicularly to the same board leading to a total size of 50 x 50 x 25 mm3 only. The simulated results are validated by comparing the measurements of a fabricated prototype. It was concluded that the design meets the target specifications over the entire bandwidth of 2 to 12 GHz with a reflection coefficient better than -10 dB (except the rejected band), isolation more than 17 dB, low envelope correlation, low gain variation, stable radiation pattern, and strong rejection of the signals in the Wireless Local Area Network (WLAN) band. Overall, compact and reduced complexity of the proposed eight element architecture, strengthens its practical viability for the diversity applications in future 5G terminal equipments amongst other MIMO antennas designs present in the literature.Comment: 25 page

Ultra-compact dual-polarised UWB MIMO antenna with meandered feeding lines

An ultra-compact dual-polarised ultra-wideband multi-input multi-output antenna made with a single-shared-radiating element and two meandered feeding lines are proposed. Miniaturisation is achieved by using a combination of techniques, including a resonant stub connected to the ground through which shorts the excessive coupled energy before it reaches the other port and minimises coupling, slots etched in the radiator that also help minimise mutual coupling, while the meandered lines allow to bring the antenna closer to the greatly reduce the overall size of the antenna. Slots etched in the radiator and the use of a stub connected to the ground through, help to minimise the mutual coupling. The formation of orthogonal surface currents provides the necessary dual polarisation. Simulated and measured results demonstrate the wideband impedance matching, low mutual coupling and low envelope correlation coefficient. This antenna has an extremely compact size (22 7 24.3 mm2, including the ground plane) that makes it an excellent candidate for portable and handheld devices. \ua9 The Institution of Engineering and Technology

Ultra-compact reconfigurable band reject uwb MIMO antenna with four radiators

A compact reconfigurable UWB MIMO antenna with four radiators that accomplish on-demand band rejection from 4.9 to 6.3 GHz is presented. An LC stub is connected to the ground plane by activating the PIN diode for each radiator. Two radiators are placed perpendicular to each other to exploit the polarization diversity on a compact 25 × 50 mm 2 FR4 laminate. Two additional radiators are then fixed obliquely on the same laminate (without increasing size) in angular configuration at ±45° perpendicular to the first two planar radiators still exploiting polarization diversity. The design is validated by prototyping and comparing the results with the simulated ones. On demand band rejection through the use of PIN diodes, wide impedance matching (2–12 GHz), high isolation amongst the radiators, compactness achieved by angular placement of the radiators, low gain variation over the entire bandwidth, band rejection control achieved by adjusting the gap between stub and ground plane, and low TARC values makes the proposed design very suitable for commercial handheld devices (i.e., Huawei E5785 and Netgear 815S housings). The proposed configuration of the UWB MIMO radiators has been investigated first time as per authors’ knowledge. ©2020 keywords: band rejected; envelope correlation co-efficient; four element MIMO; polarization diversity; ultra-wideband multiple input multiple outputEU H2020 Marie Skłodowska-Curie Individual Fellowship ViSionRF (grant no. 840854)COMSATS Research Grant Program (project no. 16-63/CGRP/CUI/ISB/18/847

Compact and Planar End-fire Antenna for PicoSat and CubeSat Platforms to Support Deployable Systems

A miniaturized planar Yagi-Uda antenna for integration with PicoSats or other SmallSat missions is proposed. Miniaturization techniques, such as meandering and 1-D artificial dielectric concepts to reduce the guided wavelength, are employed to overcome space constraints imposed by the SmallSat footprint while still maintaining good performance for the FR-4 antenna. Simulations and measurements have been carried out on the Unicorn-2 PicoSat chassis from Alba Orbital and are in good agreement. Also, antenna dimensions have been reduced between 15% and 66% when compared to a more conventional planar Yagi-Uda antenna working at the same frequency. This compactness allows for simple integration with the deployable solar panel array of the Unicorn-2 PicoSat spacecraft. Full end-fire radiation is achieved and peak gain values are about 5 dBi for the antenna when fully integrated on the satellite chassis, offering an attractive solution for downlink connectivity. This compact antenna design can also be used within an array for beam steering or integrated within the solar cell modules of other PicoSats, CubeSats and SmallSats. Applications include Earth observation, remote sensing, as well as SmallSat to ground station communications. The planar Yagi-Uda antenna may also be useful wherever end-fire radiation is required from a compact antenna structure

Printed Leaky-Wave Antenna with Aperture Control using Width-Modulated Microstrip Lines and TM Surface-Wave Feeding by SIW Technology

This letter presents a width-modulated microstrip line leaky-wave antenna (LWA) with substrate-integrated waveguide and microstrip feeding. In particular, the planar antenna system consists of an integrated surface-wave launcher and three identical rows of quasi-periodic width-modulated microstrip lines for TM leaky-wave excitation, which produces a tailored binomial-like aperture distribution on the guiding surface. The behavior of the antenna when changing the width-modulated lines for different aperture distributions is also analyzed and presented. The measured LWA demonstrates a fan beam pattern in the far field with realized gain values greater than 10 dBi and with a beam direction of about −20◦ from broadside at 23 GHz. Also, far-field measurements and near-field data indicate that the half-power beamwidth is below10◦, and the position of the main beam maximum is relatively stable, i.e., ranging from about −23◦ to −15◦ between 23 and 24 GHz. The measured prototype is also well matched over these frequencies and |S11| < −20 dB at 23.5 GHz

Organic Paper-Based Antennas

Advances in direct-write printing technology have enabled printable electronics practically on any substrates including paper. Paper is a material of very low cost, it is extremely flexible, and can be post-treated to obtain hydrophilic or hydropho-bic characteristics. Organic paper substrates have recently found extensive use in the development of antenna components. Many designs with different characteris-tics and for various applications have been made. In this chapter, a comprehensive description of printing technologies and recent dielectric measurements for paper substrates are described. Then, the time and frequency evolution of antennas on hydrophobic and hydrophilic paper substrates are presented. Antennas are approached from a principle of operation perspective and emphasis is given on their characteristics and the applications that span from omnidirectional radio fre-quency identification, WLAN and ultra-wideband antennas to recently developed QR code antennas for anti-counterfeiting and security applications