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In this paper, aberration theory will be introduced to estimate the frequency characteristics of reflectarrays. By introducing aberration theory, the mechanisms of the frequency characteristics of the beam squint and the phase errors on the aperture will be qualitatively clarified. The validity will be quantitatively verified by simulations.
Implantable medical devices are becoming smaller by the day, with more efficient electronics and smaller power demands. Nevertheless, there are some applications in which power demands are inherently high, and solutions must be found in order to keep the devices as small as possible. In this paper, we propose an antenna to be used in wirelessly powering a focal brain cooling implant based on a Peltier...
In this work an overview of the different additive manufacturing techniques will be presented. Each technique will be compared in terms of dimensional accuracy, surface roughness, and quality taking into account the most suitable applications for each one. Then, two applications will be studied: (a) fast prototyping of waveguide component designs using professional grade 3D printers for electromagnetic...
We present a novel non-iterative model based on ray analysis to characterize non-metallic, weak dielectric objects (like threat objects) on the surface of a highly conducting background (like the human body) using a focused continuous millimeter-wave sensor. For a simple constant thickness dielectric slab on a ground plane, there are five primary scattering phenomena that must be considered.
In this paper, high impedance periodic structure (HIPS) is applied to improve radiation pattern of the antenna element. The working mechanism of HIPS array is investigated. The structure could improve the surface-wave and the broad-beam radiation performance of the individual antenna element. It is benefit for the wide scan performance of the phased array. A microstrip antenna is fabricated and measured...
This paper presents the experience in designing LTCC antennas operated in F-band (90–140 GHz). A few examined structures are presented and their electrical parameters dependencies on LTCC technology limitations are shown. The paper is focused on two main aspects: the first one is related to the quality of multi-layered structures and the second one to the properties of metallization, which has a big...
This paper presents an all-metal parallel plate waveguide (PPW) Luneburg lens designed using an array of subwavelength Fakir bed of nails unit-cells. Variation of the metal post height and PPW-spacing modulates the effective refractive index. The lens operates in the Ku-band of frequencies, with more than 40% bandwidth, in a quasi-TEM mode. Broadband and low loss, with high directivity and wide field-of-view,...
Using newly developed silicon micromachining technology that enables low-loss and highly integrated packaging solutions, we are developing vertically stacked transmitters and receivers at terahertz frequencies that can be used for communication and other terahertz systems. Although there are multiple ways to address the problem of interconnect and packaging solutions at these frequencies, such as...
The localization of buried targets using Ground Penetrating Radar (GPR) is dealt with. The bi-static GPR is made of two identical Vivaldi antennas operating from 0.5 GHz to 3.5 GHz and installed in front of a sand box. The experimental data acquired in a controlled laboratory environment are validated by electromagnetic simulation. Then, both synthetic and experimental data are processed to detect...
A broadband and wide-beamwidth dual circularly polarized (CP) antenna is presented in this paper. The antenna consists of two bent dipoles placed in a crossed shape. The dipoles are individually fed with signals with quadrature phases from a 3-dB hybrid coupler chip. A metal cavity serving as a reflector is used to produce a unidirectional radiation pattern. Measurements show that the antenna has...
This paper presents a miniature antenna in Ultra High Frequency (UHF) band fabricated using liquid metal and additive technologies. Such an approach allows the accurate realization of compact and complex antenna structures. The design as well as the realization of the antenna are discussed. In order to assess the effectiveness of the proposed solution, simulated and measured results are reported....
This paper presents a wideband circularly polarized (CP) antenna with high gain and end-fire radiation. The antenna consists of two metal strips on the same side of two substrates separated at a distance of 0.09λg, where λg is the guide wavelength at the lowest operating frequency. The two metal strips are shorted together at three edges. Two pairs of tapered stubs are protruded from the metal strips...
We designed a leaky wave antenna based on X-type composite right/left handed (CRLH) transmission line. Due to the wide-band nature of X-type CRLH transmission line, the antenna can provide a wide impedance bandwidth. The antenna can provide 5dB scanning pattern from 5.6GHz to 7.6GHz. The presented antenna shows a significantly low level of cross-polarized patterns using the balanced symmetric.
A new metamaterial based subwavelength resonators configuration for X-band hollow waveguides is proposed and its application as a filter and crack detection sensor is discussed. The structure is composed of a complementary rectangular split ring resonator embedding a T-type resonator. The filter has a 0.9 GHz bandwidth at 9.11 GHz resonance frequency. The comparison between a perfect surface and a...
Under certain circumstances, plasmonic coatings could be a solution to the design of stealthy targets over the microwave range. In this communication, Perfectly Electrically Conducting (PEC) spheres with plasmonic coatings are studied in the microwave spectrum. Two main issues are raised. The first one is related to the fact that the exact computation of the Radar Cross Section (RCS) of finely textured...
A low-profile and decoupling dipole antenna array is achieved by combining patch type meta-surface with proposed parasitic cells. Based on the moment method analysis results, it is clarified that proposed parasitic cells can suppress mutual coupling of dipole antennas without additional impedance. In addition, the maximum decoupling effect of 13.3 dB is achieved.
In this paper a novel nanoparticle structure has been presented to be used in plasmonic photovoltaic to enhance its efficiency. The proposed structure enhances the light absorption inside the active layer of the photovoltaics (PV) in the visible and near infrared range of frequencies (200–900 THz). In this work, the proposed nano-antenna, nantenna, takes the shape of crescent with a gap on its narrow...
A frame antenna based on the inverted-F antenna (IFA) structure for the LTE (long term evolution) metal-casing smartphone is presented. The antenna uses a frame section along the short edge of the metal casing as the IFA's radiating strip. There are no gaps required at the two side edges of the smartphone. The frame section is connected to a feed circuit board (FCB) to achieve wider bandwidth. With...
A compact LTE frame antenna with a 2-mm narrow metal clearance for the metal-casing smartphone is presented. The antenna requires only a radiating metal frame section of about a half of the short edge of the smartphone. The metal frame section is fed by a radiating feed network, which includes a feed network and two radiating branches. The feed network includes an inductive feed path (L-path), a capacitive...
The resistively loaded 3D printed antenna demonstrates that commercially available thermoplastic filament which incorporates carbon particles can be used to print the radiating element directly, without any need to coat it with metal. Antennas used for Ground Penetrating Radar are generally resistively loaded in order to minimise late-time ringing which would obscure the returns from targets. Therefore...
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