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.
The structure of microwave diplexers based on two-dimensional (2D) electromagnetic crystals of various size has been theoretically and experimentally investigated. In the proposed devices with high-frequency selective properties two rows of microstrip quarter-wave resonators electromagnetically connected with each other and with the input of the strip conductor are used. This allows splitting the...
New multimode irregular microstrip resonators and designs of wideband bandpass filters based on them are being theoretically and experimentally investigated. A central multimode resonator electromagnetically connected with single-mode or two-mode resonators at the input and output of a structure are used in the developed filters. It is the first experience giving the possibility of combining inherent...
Recent years have seen development of variety of dual band antennas specifically for next generation wireless communications systems that will require increased bandwidth and higher data rates. These dual band antennas find application in mobile terminals, such as cellular devices or portable laptops, Wi-Fi dongles. Antennas employed in such systems have certain requirements: High gain, stable and...
A Microstrip Patch antenna for radar application is presented. There is a variety of shapes available for Microstrip patch antenna. In this paper, conventional shapes like Rectangular, Triangular and Circular Microstrip patch antenna are designed and analyzed. The antenna is designed to resonate at X-band frequency. The X-band frequency range lies between 8 to 12 Gigahertz and are widely used in radar...
The resonance characteristics of cross-dipole planar antennas are analyzed by using Theory of Characteristic Modes (TCM) in this paper. The resonant frequency, bandwidth, current distribution and other characteristics of the antenna are compared here. Unlike the traditional analysis methods, the mode decomposition is proposed here. It considering the radiating structure as a whole, seek the support...
Filter in telecommunication is a device which has function like a frequency band selector. it plays an significant role especially to select the frequency band that is wanted to be passed through. At this advanced technology era where every device is getting compact in design and size, the filter model also has been challenged in order to meet and fit the recent situation. The microstrip filter is...
Millimeter wave technology has facilitated new commercial gigabit wireless applications which require large bandwidth. Circular polarized millimeter wave antennas act as an efficient tool for suppressing the multipath fading effects seen in millimeter wave band. In this paper, a circularly polarized substrate integrated waveguide fed aperture coupled antenna at 60 GHz is presented. The circular polarization...
In this paper, the finite element method is used to investigate the influence of matching layer on the center frequency and the frequency bandwidth when the borehole wall ultrasonic imaging logging transducer operates in the mud. Our numerical results show that the characteristic impedance and the thickness of the matching layer influence the resonance frequency and the harmonic peak. With the increase...
A new type of tri-axial piezoelectric accelerometer is proposed in this study. It consists of a seismic mass and four cantilever beams that is distributed in a shape of X. Analytical model and FEM analysis were conducted to study its charge sensitivity and the fundamental/first order resonance frequency in the Z-axis, X-axis and Y-axis direction. The errors between the calculated results from analytical...
This article presents a compact piezoelectric vibration energy harvester (VEH) using multiple nonlinear techniques. Spring-plate and a manually tunable stopper-plate was used to tune the resonance frequency and broaden the bandwidth of VEH. Experimentally, the VEH can be operated in three kinds of work modes according to the gap distance between the spring-plate and the stopper-plate. The simulation...
We report on a detector-free on-chip dual frequency comb setup based on terahertz quantum cascade lasers. The presented dual-comb covers a bandwidth of 630 GHz with a centre frequency of 2.5 THz. Instead of a fast detector one of the lasers has been used as a fast detector itself. The frequency comb spacing was analysed using frequency counting techniques revealing an accuracy down to δfrep/fcarrier...
Two designs of fundamental mode rectangular to circular waveguide TE10 to TE11 mode converter are presented. The waveguide transitions are optimized for operation as an input coupler on a 372 GHz gyro-TWA for Dynamic Nuclear Polarization (DNP) enhancement of NMR imaging. A T-junction input coupler and a multiple hole directional coupler were optimized for operation between 360–384 GHz. The T-junction...
A planer antenna is developed for metallic framed tablet computer for various applications. The open slot dual antenna system for the 2G/ 3G/ LTE/ WWAN/ WiMAX bands is presented. The proposed antenna system can fit inside the tablet in such a manner that the display screen is above this antenna and the metallic frame of the tablet computer is below this antenna as a ground plane. The antenna composed...
An approach to bandwidth- and frequencyreconfigurable planar filters is proposed. Switching elements are used in a modified dual-mode microstrip resonator to independently tune the centre frequency (up to 10 %) and the bandwidth (4%) of the filter. In order to demonstrate the feasibility of the proposed approach the design of a 2nd-order tunable filter is presented along with simulation and measurement...
The key parameters for the design of a capacitive micromachined ultrasonic transducer (CMUT) cell are the dimensions of the vibrating plate, i.e. plate diameter and thickness, and the gap height. These dimensions together with the magnitude of the dc bias voltage determine the transducer's center frequency, bandwidth, and transmit and receive sensitivity. For a given center frequency, choosing the...
This paper discusses SAW-BAW-based band reject filters. They are composed of the impedance converters, where capacitive elements are replaced with SAW/BAW resonators. First, basic properties of the unit cell are studied. It is shown how basic properties of a unit cell change with the design. It is also shown that when two notches caused by the resonators are placed in proximity, two synergy effects...
Microwave moisture meters are used for fast measurement of the water content in organic and inorganic bulk materials like grain, sand, and animal feed. The operating principle is based on the very high relative dielectric permittivity and loss factor of water, so the effective electromagnetic parameters of the tested sample depend highly on the water content. The density of the test sample also influences...
Accurate diagnostics of stenosis and blood flow distribution in carotid arteries requires transducers capable of producing 3D volume images with high frame rate for real time imaging. In the process of designing a matrix probe, an important goal is to realize the acoustic stack with high sensitivity and bandwidth. In this study, we employ a finite element analysis to evaluate the effect of sub-dicing...
Our work deals with the study of the dynamic characteristics of a single circular CMUT transducer under squeeze film damping effect. A simplified analytical approach is developed for parallel plate approximation for the electromechanical behavior and the squeeze film damping. Analytically calculated results demonstrates, that trends of resonant frequency with bias voltage are defined by the ratio...
Gradient metasurfaces have recently received significant attention for the unique opportunities they offer for advanced wave manipulation. Such metasurfaces are usually discrete implementations of surface impedance profiles, which are analytically derived to yield the desired operation. Several recent numerical and experimental studies have shown that gradient metasurfaces can work very well over...
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.