نتایج جستجو برای: multifrequency antenna
تعداد نتایج: 46838 فیلتر نتایج به سال:
in recent years, the plasma antenna is a new technology for replacing the metal antennas that have been designed with better performance. in the steady state, the radiation pattern of a plasma antenna will be similar to the case of metallic antennas with the same form, size and performance at the same frequency and power. by sweeping the parameters in the plasma tube, we can change the operatin...
Electrical impedance tomography (EIT) enables one to determine and visualize non-invasively the spatial distribution of the electrical properties of the tissues inside the body, thus providing valuable diagnostic information. The electrical impedance mammography (EIM) system is a specialized EIT system for diagnostics and imaging of the breast. While breast cancer is the main target for any inv...
Dielectric Resonator Antennas (DRAs) have received increased interest in recent years for their potential applications in microwave and millimeter wave communication systems. DRAs are normally used with the support of a ground plane. The radiation and impedance properties therefore depend not only on their physical dimensions and dielectric properties, but also on the size of the ground plane. ...
In this paper a dual band and high gain H-plane horn antenna implemented by substrate integrated waveguide (SIW) using a single layer thin substrate is introduced. The proposed antenna consists of five parts of rectangular waveguide with different width arranged in a staircase manner to allow mode combination of fundamental and higher propagating modes of the structure. By adjusting the length ...
BACKGROUND Steady state responses (SSRs), between 75 and 110 Hz, evoked by auditory amplitude modulated single or multiple tone stimuli, may be used to estimate objective hearing threshold. METHODS The aim of this study was to compare SSRs and click-evoked auditory brainstem responses (ABRs) in both ears of 20 adults (10 males and 10 females, aged between 24 and 36 years) with normal hearing ...
Time-harmonic shear wave elastography is capable of measuring viscoelastic parameters in living tissue. However, finite tissue boundaries and waveguide effects give rise to wave interferences which are not accounted for by standard elasticity reconstruction methods. Furthermore, the viscoelasticity of tissue causes dispersion of the complex shear modulus, rendering the recovered moduli frequenc...
PURPOSE To test in vivo magnetic resonance elastography (MRE) of the human intervertebral disk (IVD). METHODS The feasibility of MRE in IVD was demonstrated in ex vivo bovine disks. Sixteen asymptomatic volunteers underwent multifrequency MRE of the lumbar spine (IVD L3/4 and L4/5, n = 32) using a posterior plate transducer connected to a loudspeaker and operated at five frequencies from 50 t...
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