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15 Cards in this Set
- Front
- Back
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What type of transmission line is the primary method of transporting microwave energy?
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Waveguide
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What two boundary conditions must be met for energy to travel through a waveguide?
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1. An electric field, to exist at the surface of a conductor, must be perpindicular to the conductor.
2. A varying magnetic field must exist in closed loops parallel to the conductors and perpindicular to the electric field. |
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What is group velocity?
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The velocity of wavefronts traveling down a waveguide. Group velocity is slower than the velocity of wavefronts through space.
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What are the two categories of modes in waveguides?
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Transverse electric and transverse magnetic
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What are the three basic categories of waveguide input/output methods?
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Probes, loops, and slots
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What are the matching devices used in between the waveguide and the load?
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Irises, conductive posts and screws can also be used
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What devices are used to prevent standing waves at the end of a waveguide system?
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Waveguide terminations (horns or dummy loads)
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What type of devices combine magnetic properties with a high resistance to current flow?
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Ferrite devices
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What is a velocity modulated tube, that when used as an amplifier, requires at least two resonant cavities, the buncher and the catcher?
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Klystron
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How is electron transit time controlled in a reflex klystron?
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By the repeller voltage
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What three fields that influence operation exist within a magnetron?
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DC electric field, AC electric field, and magnetic field.
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What are the two basic types of magnetrons?
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Negative-resistance and electron-resonance
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What is a two-terminal diode that acts as a variable capacitance and is the active element of parametric amplifiers?
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Varactor
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What is a wide-bandwidth, velocity-modulated tube used primarily is an amplifier?
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TWT (traveling wave tube)
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What are two types of microwave transistors?
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Gallium-arsenide FET amplifiers and Silicon-bipolar transistor amplifiers
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