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A planar array of 48 parasitic dipoles above a ground plane fed by a single active dipole at 5 GHz, was designed to afford a pencil beam pattern of moderate gain and bandwidth. Measurements agree well with theory.
In this work a capacitively-fed modified folded-slot antenna for body area network applications is presented. The antenna is placed on a uniform cylinder, which simulates a human forearm. The electromagnetic parameters of the human body were calculated as a weighted average based on the fat, muscle, skin, blood and bone composition for the arm. The experiment was conducted by simulations using Ansys...
In this work, a small rectangular patch antenna for body area network application at 2.4 GHz is presented. The antenna is modeled on a uniform cylinder which simulates a human forearm. The electromagnetic parameters of the forearm were calculated as a weighted average based on the arm fat, muscle, skin, blood and bone composition. The experiment was conducted by simulations using Ansys HFSS. The simulations...
A cavity-backed annular slot-ring antenna with reconfigurable VO2 shorts is designed to take advantage of the insulator-to-metal transition of the material. By selectively activating the shorts, the antenna presents a change in resonant frequencies from 6.3 GHz, when no shorts are active, to 8.25 GHz, when the short located at 80 degrees from the feed point is active. The antenna gain varies from...
Polyimide aerogels were considered to serve as a filling for millimeter-wave waveguides. While these waveguides present a slightly higher loss than hollow waveguides, they have less losses than Duroid substrate integrated waveguides (less than 0.15 dB at Ka-band, in a 20 mm section), and exhibit an order of magnitude of mass reduction when compared to commercial waveguides. A Ka-band slotted aerogel-filled-waveguide...
A planar array composed of 41 parasitic dipoles above a ground plane, fed by an active dipole at 5 GHz was designed to obtain a pencil beam pattern with a moderate gain and bandwidth. Experimental results are in good agreement with the theory and show a pattern with an 18.78 dB gain, a sidelobe level (SLL) of -15 dB, an impedance bandwidth of 16.53% (the frequency range over which the value of S11...
In this paper, two current controller schemes, based on repetitive controllers and proportional+resonant controllers using second order generalized integrators connected in parallel, are proposed and compared for shunt active power filters. Both controllers are well suited due to their optimum tracking and harmonic rejection capability. The objectives of this paper are: to analyze both controllers...
This paper presents a design tool for the synthesis of pipeline ADCs which is able to optimally map high-level converter specifications, such as the required effective resolution, onto electrical-level parameters, i.e., transistor sizes and biasing conditions. It is based on the combination of a behavioural simulator for performance evaluation, accurate models of the converter components, and an optimization...
We have analyzed the feasibility of performing quantum key distribution (QKD), in earth-satellite and intersatellite links, with four quantum cryptography protocols: BB84 and SARG04 with and without decoy states. In order to facilitate the protocols comparison we have computed the rates using the optimal mean photon number for each protocol and for each distance. Furthermore, we have formulate a lower...
This paper presents the K-band traveling wave tube amplifier (TWTA) developed for the lunar reconnaissance orbiter and discusses the new capabilities it provides.
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