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In this article, a super compact enhanced-bandwidth (EB) rat-race coupler (RRC) is initially proposed based on the combined technology of fractal geometry and lumped-element composite right/left handed transmission line (CRLH TL). The close-form broadband derivation and a set of design guideline for fractal implementation are provided which should be a reference value for future design. Fractal perturbation...
Ultrafast terahertz (THz) transients are of great interest for linear and nonlinear THz spectroscopy and compact particle acceleration. Tilted-pulse-front (TPF) [1] THz generation in lithium niobate (LN) has become ubiquitous due to its compatibility with easily accessible high-power 800 nm/1 µm laser technology. However, the use of diffraction grating (DG) based TPFs (DG-TPFs) present formidable...
In this paper, the design and particle simulation of a Ka-band stagger tuned gyro-twystron amplifier is presented. The concept of stagger tuning in gyro-twystron improves the bandwidth along with high RF output power which is suitable for radar application. The complete amplifier structure is modelled in “CST particle studio” for studying the beam wave interaction behaviour. The PIC simulation predicted...
In this work, two electro-optic (EO) modulation schemes based on the Pockels effect — the quasi-linear and nonlinear EO modulation are compared and analyzed. Then, we find that the modulation efficiencies with these two schemes are at the same level relation of Vπ and L, but the quasi-linear scheme has to face the critic limitation in the realistic EO modulation implementation process. Thereby, with...
The rise of big data and cloud computing applications is driving an explosion in the growth of data centers (DCs), and is already resulting in networking bottlenecks and performance degradation. The size and capacity of DCs are being constrained by the traditional packet-based switching architectures due to high energy consumption.
Planar chial meta-surface (PCM) is a class of meta-materials, consisted of a two dimensional surface grating with a chiral-shaped pattern in its unitcell. It has been reported that appropriate choice of film materials and the shape of chiral pattern made it possible to induce giant optical activity (polarization rotation) [1]. In this study we focused on Si/Si3N4/SiO2 PCM and investigated its potential...
The microstrip wideband antenna has attracted much attention due to the applications of multiple wireless communication systems, such as the global positing system (GPS at 1.575 GHz), the digital communication system (DCS at 1.8 GHz), the international mobile telecommunications-2000 (IMT-2000 at 2.1 GHz), the wireless local area network (WLAN at 2.45 GHz), the long term evolution-2600 (LTE2600 at...
This paper presents a third-order digital tunable bandpass filter based on digitally tunable capacitor loaded open ring resonator. Magnetic dominated mixed coupling is utilized to make the coupling coefficient meet the requirement of stable bandwidth response. Electric source-load coupling is designed to generate a transmission zero for improving the frequency selectivity. This filter is designed,...
In this letter, a composite metasurface for end-fire scattering is designed, fabricated and characterized. Based on the principle of scattering cancelation and method of end-fire antenna array, we proposed the lattice-like arrangement composite metasurface (LACMS). When EM waves normally illuminates on the metasurface, the scattering energy redistributes to the end-fire direction. Compared with the...
This manuscript represents the two half circular gap coupled disk patch antenna stacked with D.G.S. (Defected Ground Structure) for dual-wideband application. The antenna has an overall size of 40.0×40.0×1.6mm3 and gives the results of dual band performance. The proposed antenna can be used in military communication, wideband global satellite communication systems (WGS) (9.43–10.08 GHz) and in Airport...
In this paper, the performance of a new dual-band Frequency Selective Surface (FSS) structure based on square ring and three-pole loading was presented. Two applications which were carried out to verify the feasibility of the FSS structure are using the FSS as the high impedance surface to design absorbing material and as the radome to reduce the antenna Radar Cross Section (RCS). The wave-transparent...
This paper compares sequential subarrays of dielectric resonator and patch antennas in terms of circular polarization and impedance bandwidths, and realized gain using hybrid ring feeding networks. Aperture coupled antenna is used as the basic structure.
The present work investigates a novel cylindrical dielectric resonator antenna (CDRA) excited by a coaxial feed monopole, which is mounted on a circular substrate with a deformed ground plane. A vertical electric monopole is placed in the center of the DR. The wideband characteristic is achieved by the deformed ground plane. The features of the proposed antenna meet the essential requirements of X-band...
This paper proposes a novel heart-shaped band-notched UWB antenna with compact and simple structure. The antenna comprise of a microstrip feeding line, a heart-shaped patch to achieve UWB characteristic, and a defected ground with bevels to obtain good impedance match and stable gain in the operating band. The band-notched characteristic is achieved by a U-shaped slot on the patch. The measured results...
The features of omnidirectional band gap (OBG) in the two-dimensional (2D) plasma photonic crystals (PPCs) with triangular lattices are theoretically investigated as the off-plane incidence wave vector is considered, which are composed of the unmagnetized plasma cylinders inserted into the homogeneous and isotropic dielectric background. The simulated results show that not only a flatbands region...
Frequency selective surfaces (FSSs) are planar structures composed of a periodic array of unit cells that filter electromagnetic (EM) waves impinging on the surfaces. They have been widely used in stealth technology, electromagnetic countermeasure, and communication systems [1, 2]. Typical FSSs are composed of metallic grids or dipole arrays, which exploit the strong interactions between EM waves...
This paper presents the design of tri-band planar dipole antenna for PCS and WLAN services. A modification is made in the previously presented dipole antenna design [1]. The configuration of the proposed dipole antenna is given in Figure 1(a). The antenna design consists of a printed dipole and two parasitic elements which are behaving as resonators by coupling from the driving element. The proposed...
The generation of continuous THz-waves by photomixing has several promising features, such as extremely-wide frequency tunability, very narrow linewidth, good frequency stability, and the ability to transmit high-frequency signals through low-loss optical fibers. To make such a scheme work effectively, we developed an InP/InGaAs uni-traveling-carrier photodiode (UTC-PD) [1, 2]. The UTC-PD has a unique...
In this research article, a compact dual band asymmetric coplanar strip-fed printed antenna is designed and presented for Bluetooth, WLAN/WiMAX and public safety applications. The dual frequency operating bands (2.45 GHz and 5.25 GHz) have been achieved by attaching two simple meander shaped radiating strips to the ACS feed line. The proposed antenna geometry is printed on a low cost FR4 substrate...
The need to deliver efficient wireless services has spurred many network providers to access higher frequency bands on the millimetre-wave (mm-wave) platform which caters for larger system bandwidth and throughputs. This option offers networks the benefits of increased carrier flexibility and robust channel capacity, for many user applications, which are currently in high demand. The 60 GHz band is...
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