The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A square helix slow wave structure is proposed for high gain millimeter wave TWTs. The electromagnetic characteristics of this structure are calculated by HFSS. It is shown that, compared with the equivalent circular helix with the same cross section perimeter, the square helix structure holds higher interaction impedance and lower normalized phase velocity, which indicates higher output power and...
A theoretical model for the arbitrarily-shaped groove staggered double-grating array waveguide (SDGAW) slow-wave structure (SWS) is used to calculate the characteristics of dispersion and coupling impedance for a step-shaped staggered double-grating slow wave structure for W band TWT application. The results are compared with those obtained by CST-MWS code simulation.
Layered metasurfaces made of gold loop antennas are proposed for beam engineering at telecom band. Any transmitted amplitude or phase profile is designable by modifying the loop configuration cell by cell and layer by layer. Applications of 3D beam scanning and focusing are studied numerically and high efficiency of > 80% is achieved thanks to the low ohmic loss and the perfect impedance match...
A novel slow wave structure (SWS) called sine ridge waveguide (SRWG) has been proposed for a wideband high-power terahertz radiation source. The cold bandwidth of the SRWG is similar to the sine waveguide structure. Meanwhile, the interaction impedance of the SRWG is about 70% higher than sine waveguide at 0.65THz with the same dimensional parameters. Furthermore, it possesses low ohmic losses and...
A new technique for the analysis and attenuation calculation of sub-millimeter waveguides is proposed in this paper by dividing the domain into several slices, in which the propagation constant ß and impedance Z for each slice were calculated and then used to estimate the overall attenuation as well as the reflection and transmission coefficients. Variations of losses with the waveguide dimensions,...
This study is aimed at development of a moderate power sheet-beam traveling wave tube (TWT) amplifier with grating slow-wave structure (SWS). A fast and accurate code for calculation of eigenwaves in the grating SWS is developed, and results of numerical modeling of a G-band TWT are presented. Electron gun producing an intensive sheet electron beam is developed. Beam focusing and transportation is...
In this paper, a two-layered frequency selective surface with miniaturized elements is proposed for millimeter wave and terahertz applications. The advantages of this design are a harmonic free transmission response and low sensitivity of its frequency response to the angle of incidence. Performance of the designed structure is verified using full-wave electromagnetic simulations. The results show...
This article describes a semi-coaxial through glass via(TGV) interposer structure for high frequency three dimensional(3D) system applications. In order to overcome impedance mismatch in high frequency transition, a semi-coaxial structure is designed. The glass is 200 μm thick and the via's diameter is 50 μm. Re-distribution layer (RDL) line to TGV transition structure is designed and simulated to...
We report the design, fabrication and characterization results of 585 GHz focal-plane arrays (FPAs) using Sb-based heterostructure backward diodes (Sb-HBDs) integrated with lens-coupled folded-dipole antennas (LC-FDAs). Under impedance matching condition, a responsivity of 9,800 V/W at 585 GHz for a single array element detector can be achieved based on simulation results. In order to expand the single...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.