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.
Through silicon vias (TSVs) are arranged to form a rectangular resonant cavity to improve performance of silicon based antenna in this paper. On the basis of fundamental theory of rectangular resonant cavity, the model of cavity made of through silicon vias is analyzed. Considering the size of millimeter-wave antenna, the three dimensions of cavity for mode TE101 is calculated. Applying the resonant...
Directly current-modulated 980-nm vertical-cavity surface-emitting lasers (VCSELs) with oxide-aperture-diameters of 1.5-μm exhibit small-signal −3-dB modulation bandwidths of 31 and 25-GHz and maximum single-mode light-output-powers of 3 and 2-mW at 25 and 85°C, respectively. The side-mode-suppression-ratio exceeds 40-dB at bias currents above threshold.
This paper proposes a compact circularly-polarized (CP) Substrate Integrated Waveguide (SIW) cavity antenna for 5G application operating in 28 GHz band. The antenna consists of a patch with perpendicular-arrows-shaped on a SIW structure. Longitudinal slot etched on the SIW top metallic surface are also used to excite the radiator. The CP radiation is obtained by using a three-quarters-circle-shape...
A novel broadband circularly-polarized (CP) antenna fed by strip-line is proposed. The CP operation is achieved by corners truncated and can be significantly improved by introducing a pair of half loop strips around two opposite corners of the square patch. The bandwidths for the axial ratio (AR < 3 dB) and relative impedance (|S11| < −10 dB) is 7.6% (16–17.2 GHz). The proposed antenna also...
For aperture sizes greater than 0.25λ the Vivaldi antenna design and implementation is quite easy. Criticality sets in, if the aperture size is less than 0.25λ. Keeping this aspect in view, in this paper, parametric studies have been carried out on a Vivaldi antenna with a novel taper with exponential plus sinusoidal function. For matching at the lower frequency end, a novel additional circular cavity...
In this paper, a directive, robust, and light weight antenna for Unmanned Arial Vehicles (UAV) communication applications is presented. The proposed antenna exhibits dualband operation from 4.53 GHz to 5.16 GHz with a bandwidth of 13.26% and from 5.3 GHz to 5.9 GHz with a bandwidth of 10.7%. Furthermore, it is characterized by good and stable radiation characteristics with overall realized gain of...
Air-coupled transducers are used to conduct fast non-contact inspections in NDT. Normally, the bandwidth of a conventional transducer can be enhanced, but with a cost to its sensitivity. However, low sensitivity is very disadvantageous in air-coupled NDT. This paper presents a methodology for improving the bandwidth of an air-coupled diaphragm transducer without sensitivity loss by connecting a number...
Capacitive Micromachined Ultrasound Transducers (CMUTs) have become a better alternative to traditional piezoelectric transducers because of their better impedance matching characteristic and wider bandwidth. These advantages make CMUTs ideal for medical ultrasound imaging, ultrasonic flow metering, gesture sensing and other airborne applications. However conventional vacuum CMUTs have narrow bandwidth...
Air-coupled transducers are used to conduct fast non-contact inspections in NDT. Normally, the bandwidth of a conventional transducer can be enhanced, but with a cost to its sensitivity. However, low sensitivity is very disadvantageous in air-coupled devices. This paper presents a methodology for improving the bandwidth of an air-coupled micro-machined ultrasonic transducer (MUT) without sensitivity...
Dispersion compensation is vital for the generation of ultrashort and single cycle pulses from modelocked lasers across the electromagnetic spectrum. However, no such scheme have been successfully applied to terahertz (THz) quantum cascade lasers (QCL) for short and stable pulse generation in the THz range. Here we show a monolithic on-chip compensation scheme for a modelocked QCL, permitting THz...
A G-band rectangular beam multi-gap Extended Interaction Klystron (EIK) with unequal-length gaps is proposed. The high-frequency features indicates that the designed model has wide frequency intervals with π mode, which has a good uniformity in field distribution with the maximum (R/Q)•M2. The PIC simulation shows a stable output power of 1378 W without oscillation in 218.9 GHz, with the efficiency...
In this paper, a wide-band circularly polarized (CP) crossed dipole antenna is proposed. The CP crossed dipole antenna is backed by a cavity reflector to achieve wide-band CP radiation with enhanced gain and uni-directional pattern accompanied by high front to back lobe ratio. A comprehensive study on the effect of the vertical walls of the cavity reflector on the CP radiation performance has been...
The dependence of the quality factor (Q) of a reverberation chamber as measured using a time-domain approach on the total bandwidth included in the time-domain signal has been investigated. Time-domain measurement of the Q factor of a mechanically stirred, metal cavity has been been performed using synthesized pulses of different bandwidth with the cavity both loaded and unloaded by absorbing material...
We report a broadband ytterbium-doped femtosecond fiber laser around 980nm. The cavity is based on the all-normal dispersion (ANDi) configuration, including a diffraction-grating which plays a crucial role as a narrow-band spectral filter. The spectral bandwidth of mode-locked pulse reaches 11.4 nm, which approaches the gain bandwidth (about 13nm) of the ytterbium doped fiber around 980 nm. The pulse...
The huge increase of datacom traffic requires laser sources of ever-widening modulation bandwidth. Vertical-Cavity Surface-Emitting Lasers (VCSEL) are strategically relevant given that their wide use for short communication links such as in datacenters and are, in light of recent developments, good candidates to address such demands. We propose to increase the modulation bandwidth by vertically integrating...
Passive optical resonators are important tools for enhancing the sensitivity of spectroscopic measurements [1], and for enhancing the peak and average power of femtosecond laser pulses to the levels necessary for high-order harmonic generation (HHG), e.g. for the generation of XUV frequency combs [2]. The optical bandwidth and thus the pulse duration in such enhancement cavities (ECs) is typically...
Lasers with high optical frequency stability have played a significant role in numerous applications including metrology and spectroscopy. A laser with better frequency stability allows shorter integration time and higher accuracy. To achieve this, one of the most crucial factors is the stability of the cavity length of the laser. The length of the cavity is always disturbed by environmental noises...
Hybrid quantum technologies seek to combine the advantages of two individual quantum architectures by transferring the information between the two systems. We want to benefit from the high mobility and ease of transmission of photons for quantum communication and exploit the excellent readout and storage capabilities of atomic qubits as a quantum memory, which is essential to build up quantum repeater...
To study the relationship between the performance and the size of the filter, a W band rectangular waveguide bandpass filter was designed. First, a four cavity bandpass filter was designed, and then improved its structure to generate a transmission zero on both sides of the passband. The cross coupling structure reduces the rectangular coefficient by 25.7% and enhances out of band rejection. The simulation...
In this paper, a novel design of bandpass filter with both reconfigurable center frequency as well as controllable fractional bandwidth is presented. Proposed is a three-pole configurable evanescent mode (CEVA) filter that based on low loss Rogers 5880 and consists of two arrays of metallic electromagnetic bandgap (EBG) posts that oriented in both horizontal and vertical direction. In simulation model,...
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.