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Inverse Compton Scattering provides a unique way to produce quasi-monochromatic X-rays via the interaction of relativistic electrons with a laser pulse. This process has the advantage of producing a very high flux of X-rays with energies above a few tens of keV for a modest electron beam energy. In addition the output beam divergence is much larger than in classical synchrotron light sources and the...
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...
The main goal of this research is to design, fabricate, and test deployable VHF antennas for 6U Cubesat platforms to enable validation of root zone soil moisture (RZSM) estimation algorithms for signal of opportunity (SoOp) remote sensing over the 240–270MHz frequency band. The proposed work provides a strong foundation for establishing a technology development path for maturing a truly global direct...
The goal of the NASA SMAP L-band Active and Passive mission is to retrieve soil moisture with 4% accuracy for vegetated surfaces that have vegetation water content (VWC) less than 5 kg/m2. The satellite was launched in January 2015. After the failure of the radar on July 7, 2015, there has been increasing interest in using the Sentinel C-band radar data for the active part of the mission. In using...
Soil moisture plays a key role in many hydro-meteorological processes. Remote sensing of soil moisture in a bistatic mode has attracted increasing attention in recent years. Systematic simulation of bistatic scattering behaviors from a rough surface offers physical insights into designing bistatic radar configuration and field campaigns. In the study, the sensitivity of bistatic scattering to soil...
Recently the increasing anti-terrorism and disaster rescue operations underscore the requirement for effective detection and recognition of finer-grained human activity. Currently, the most effective technology is usually realized by exploiting time-frequency analysis to extract the micro-Doppler (MD) signature difference formed by different parts of the body movement. However, for inherently nonlinear...
Silicon optical modulators, one of the essential building blocks of silicon photonics technology, have made rapid progress in the last decade and start to show the competitive performances when comparing to traditional LiNbO3 and III–V optical modulators.
Rapid growth in the demand for data traffic has facilitated the introduction of high-capacity digital coherent transmission for long-haul optical fiber networks. For successful digital coherent transmission to metro-area networks or shorter ranges, the cost and size of transmission equipment and its components must be further reduced. Silicon photonics is a fascinating technology to meet this requirement...
Existing head-mounted Virtual Reality presents depth perception mainly through stereoscopic display technology which is based on biocular-parallax. The loss of nonocular physiological depth cues resulted in visual fatigues, an urgent open problem inhibiting the forward steps of head-mounted Virtual Reality. The super multi-view (SMV ) technique is seen as an ideal 3D display technology, which can...
Due to occurrence conditions of the coal and nature are different in the different coal mine and the different coal seam in the same mine coal mine, and the crushing of coal is random, so the force of heading machine during the cutting process is also different. A large number of mechanical characteristics can be obtained by measuring accurate cutting force, which will provide important gist for evaluating...
The total-internal-reflection (TIR) switch hasa lot of advantages as a true amplitude-control device, providing insensitivity to wavelength and mode of light and also to circumferential temperature. The TIR switches have been commercialized as the digital optical switch for optical communication systems, mainly based on polymer materials and thermo-optics. A representative example is a thermo-optic...
Optical modulators are central to a large number of applications in photonics particularly in the area of communication as they provide the function of writing electrical data onto an optical carrier. Silicon photonics provides a route to the realisation of low cost photonic integrated circuits through fabrication which is synonymous with CMOS electronic fabrication, i.e., high volume and high yield...
The respirable dust quality can be obtained by measuring the oscillating frequency of the oscillating tube, which can realize respiratory dust monitoring combined with flow measurement. But the manufacturing process of the hollow cone tapered element stainless steel oscillating tube is complicated, and the finished product rate is low; the product quality dispersion is larger than the others. With...
A new fractal like tree structure of circular patch antennas for multi-band and wide-band challenges in 5G technologies is presented in this paper. The elementary structure is shown in Fig. 1. The antenna is designed on low cost Rogers RT/duroid 5880 (tm) substrate fed by a 50-ohm micro-strip line. The antenna is simulated in High Frequency Structure Simulator Software (HFSS). The proposed antenna...
MOSFET type photodetectors, also known as phototransistors, have the advantages of not only high photo sensitivity and responsivity, but also integrability into conventional CMOS chips. In this work, flexible phototransistors with a back gate configuration based on transferrable single crystalline Si nanomembrane (Si NM) have been demonstrated [1–3]. The schematic illustration of the device fabrication...
Over the past two decades, great efforts have been made in the study of routing and manipulating light waves at the subwavelength scale with open nanostructures such as photonic crystal waveguides (PCWs), surface plasmon waveguides (SPWs), and coupled resonator optical waveguides (CROWs), for their great potential in many photonic technologies such as highly integrated photonic signal-processing systems...
In this work, we experimentally explore the possibility to circumvent some drawbacks of silicon ring-resonator index sensors [1, 2] by a new approach relying on the detection of the micro-ring resonator spectrum overall envelope. In the purpose of strong light-matter interaction, slot waveguides have been considered to operate in the near infra-red [3]. As a proof-of-concept experimental study, hollow...
Simulating laser ablation on an atomistic scale is a demanding task which requires millions to billions of atoms for sample sizes in the nano- to micrometer range.
Silicon photonics can potentially transform the photonics technology owing to its low-cost fabrication and large-scale integration advantages. To this end, integration density will be the key factors for its future development. This talk will review our work on high-density waveguide integration based on waveguide superlattices. Half-wavelength pitch waveguide arrays with very low crosstalk have been...
In this paper, a low cost broadband single layer reflectarray is proposed for X-band applications. The proposed reflectarray consists of truncated circular patch coupled to octagonalring delay line. The unit element is optimized to work at X-band with the center frequency of 10 GHz. A broad reflection phase range of more than 600° is obtained by varying the length of delay line. The reflectarray is...
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