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 simple monopole antenna for hepta-band LTE/WWAN (824 ∼ 960/1710∼2690 MHz) Metal-framed mobile handset is proposed. Two slits are applied at the upper part of the metal frame. And the metal frame between slits is used for monopole antenna itself. The proposed monopole antenna structure is simple, slim and it has just one feed-line. For producing multiple resonances, impedance matching methods with...
The Lamb waves and horizontal shear waves' propagation in LiTaO3 thin plate is investigated as a function of Euler angles. Both velocity and electromechanical coupling factor largely depend on the plate's thickness. Around (0°, 30°, 0°), LiTaO3 thin plate has a high velocity and a suitable coupling factor for a high frequency filter. Authors fabricated A1 mode Lamb wave resonators in (0°, 39°, 0°)...
Compact Microstrip band pass filter (BPF) with nearly 4 GHz bandwidth based on defected ground structures (DGS) is proposed in this paper. Novelty of the design lies in the method of coupling and the defects used. Stepped Impedance Resonator (SIR) DGS and an L-shaped defect are introduced in the design. The width of the SIR-DGS is used to vary the coupling. The key advantage of this configuration...
A wideband ±45° dual-polarized base station antenna for 2G/3G/LTE bands is proposed in this paper. By embedding a metallic strip to the traditional loop dipole antenna and adopting T-shaped coupling feeding structure, a wideband impedance bandwidth from 1.7–2.7GHz with SWR≤1.5 was achieved, the isolation of two ports was more than 25dB. A stable 3-dB beamwidths of 65.82°±3.64° at horizontal plane...
An aperture-coupled stacked patch microstrip antenna based on Low-Temperature Co-fired Ceramic (LTCC) technology is presented in this paper. Inspite of using an antenna substrate with high permittivity of 7.1 and only 200 µm thickness, wide bandwidth characteristic is achieved by means of coupled resonances. The antenna physical features contributing to the coupled resonances include a rectangular...
In this continuous wave W-band TWT, a phase velocity step-tapering folded waveguide circuit was used instead of the uniform interaction circuit to improve the electron efficiency. The optimized pitch profile was proposed. The first prototype tube was assembled and tested. The output power in the 4GHz bandwidth of W-band was above 55W with about 15% overall efficiency.
The eigenwave dispersion of Q band 3-folded helical corrugation waveguide is simulated using CST software. The electron beam 98kV and main magnetic field 0.87T are given by the eigenwave dispersion for Q-band Gyro-TWT using helical waveguide. The beam-wave interaction procedure is simulated using a PIC code, in which TE11 and TE21 coupling mode transform and a right-rotating large-orbit electron bunch...
This work presents a solution for matching electrically small antennas in broadband and multiband applications where efficiency levels should not be very low. To do this, a two-port antenna concept is introduced to design an embedded LC structure in the architecture of the antenna. Simulation results are presented in the upper part of the VHF band (80–180 MHz) and in the lower part of the UHF band...
The recently introduced method for defining bandwidth-optimal matching circuits for arbitrary load impedances has been utilized in the design of handset antennas. In this paper, the bandwidth estimator approach is widened. Bandwidth estimators are first reviewed. Next, a tablet antenna example illustrates how an efficient analysis tool can boost the design and lead to a simple antenna solution. The...
A modified folded-waveguide (FW) delay line for traveling-wave tubes (TWTs) is proposed. The amplifier performance is assessed by full-wave and interaction simulation. Properly designed nose cones are shown to enhance the beam-wave coupling. This, in turn, improves the amplifier gain, a weak point of conventional FW-TWTs. The achievable beam efficiency is increased without sacrificing too much bandwidth.
Mumtimode fibers (MMF) are increasingly used for high speed, short haul applications. Several techniques, both optical and electronic, are being researched to enhance the capacity of MMFs. This paper reports an improved version of the center-launching technique, viz. mode-field matched twin-spot launch, which can be used to excite the fundamental mode alone in an MMF. This technique reduces the differential...
We propose a new reconfigurable optical switch based on thermally controlled EIT-like effect in embedded ring resonators (ERR). By controlling the power splitting ratio of dual directional couplers through a transverse temperature gradient, a narrow band intensity modulated optical switch can be achieved. Results show the ERR-based thermally controlled resonant structure has an on-state transmission...
We present the design, simulation and measurements of broadband gratings couplers with a variable grating pitch. The measured 3 dB bandwidth was over 110 nm. The gratings employ diamond-shaped sub-wavelength grating (SWG) structures for dispersion control and a varying pitch along the transmission axis.
This work addresses center frequency and bandwidth tunable filter for implementation in RF base-station front-ends. The filter is fabricated using functional thick-film layers of Barium-Strontium-Titanate (BST). The deposition of BST layers is performed locally in a screen printing process. The fabricated varactors have a Q-factor around 40 at 1 GHz, a tunability larger than 50% and a measured IP3...
In this paper, balanced bandpass filter (BPF) with controllable dual passband performance is presented. Based on the voltage distribution of traditional half-wavelength resonator, the stub-loaded theory with independently controlled differential-mode resonances is presented and applied to design dual-band balanced BPF with independently controlled passband locations. Then, except for the main coupling...
Antennas can couple if they are placed near each other, such as on portable wireless devices. Such coupling is often viewed as a nuisance that is a detriment to system performance. We show how coupling, if exploited properly, can lead to higher achievable data rates than an equivalent uncoupled system. Our conclusions build on some recent results on the bandwidth of coupled radiofrequency systems.
To allow a maximum theoretical data-rate of 25Gb/s over a 1km distance using 64QAM, an E-Band system should feature a 20dBm-output-power TX and an RX with 10dB maximum noise figure (NF) over two bands of 5GHz from 71 to 76GHz and 81 to 86GHz [1]. To minimize the NF of a fully integrated RX front-end and to compensate for the low conversion gain and high noise of the following mixer, a broadband LNA...
In this paper, we report on a reconfigurable bandpass filter for X-band applications. The filter is composed of coupled X/2 microstrip line resonators. Center frequency tuning of each resonator is achieved using an RF switch based on a phase change chalcogenide compound, germanium telluride, which switches in and out a loading capacitor. A combination of electric and magnetic coupling between the...
Demonstrations of mm-Wave arrays with >50 elements in silicon has led to an interest in large-scale mm-Wave MIMO arrays for 5G networks, which promise substantial improvements in network capacity [1,2]. Practical considerations result in such arrays being developed with a tiled approach, where N unit cells with M elements each are tiled to achieve large MIMO/phased arrays with NM elements [2]....
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.