CAD Antenna Designer Practical Applications and Systems Flashcards
6 cards from real CAD practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CAD Antenna Designer Practical Applications and Systems flashcards as text
In satellite communication ground station design, why is an offset-fed parabolic reflector preferred over a prime-focus fed reflector?
Answer: The feed and its supports do not block the aperture, improving efficiency and reducing sidelobe levels
An offset-fed reflector positions the feed horn outside the main beam path, eliminating aperture blockage by feed supports and thereby improving gain and reducing sidelobe/cross-polarization levels.
What is the function of a Butler matrix in a switched-beam antenna system?
Answer: A passive beamforming network that produces orthogonal beams from multiple input ports
A Butler matrix is a passive, reciprocal beamforming network that generates multiple fixed orthogonal beams by applying specific amplitude and phase distributions across an antenna array.
In RFID systems operating at 915 MHz (UHF), what antenna polarization is typically used at the reader to maximize tag read reliability regardless of tag orientation?
Answer: Circular polarization
Circular polarization at UHF RFID readers ensures reliable tag reads regardless of the tag's physical orientation by avoiding polarization mismatch loss.
When designing a wideband antenna for spectrum monitoring from 20 MHz to 6 GHz, which antenna type best covers this range with a single element?
Answer: Biconical or discone antenna
Biconical and discone antennas achieve very wide impedance bandwidth across multiple decades of frequency, making them suitable for broadband spectrum monitoring with a single physical element.
What happens to the beamwidth of a parabolic dish antenna as dish diameter increases relative to wavelength?
Answer: Beamwidth narrows, increasing directivity
As dish diameter increases relative to wavelength (D/λ), the antenna aperture grows, narrowing the beamwidth and increasing directivity proportionally.
In a phased array antenna used for electronic warfare jamming, what technique allows the array to simultaneously null a threat signal direction while maintaining gain toward a protected communication link?
Answer: Adaptive nulling using digital beamforming with feedback from the received signal
Adaptive nulling places pattern nulls toward interferers while preserving main beam gain in desired directions by iteratively adjusting element weights via a feedback algorithm.