CAD CAD Antenna Designer Practical Applications and Systems

Question 1

In a cellular base station, what is the primary purpose of using a sector antenna instead of an omnidirectional antenna?

Accepted Answer

To concentrate radiated power into specific angular regions for increased capacity

Answer

To reduce tower height requirements

Answer

To eliminate the need for a transmission line

Answer

To comply with FCC Part 15 power limits

Question 2

What type of antenna is most commonly used in GPS receivers due to its ability to receive circularly polarized signals from any satellite elevation angle?

Accepted Answer

Patch (microstrip) antenna

Answer

Dipole antenna

Answer

Log-periodic antenna

Answer

Helical antenna

Question 3

Which antenna characteristic is most critical when designing a direction-finding (DF) system for locating an unknown transmitter?

Accepted Answer

Sharp azimuthal pattern with well-defined null direction

Answer

Maximum gain in all directions

Answer

Broadband impedance match below −10 dB

Answer

Vertical polarization only

Question 4

A MIMO wireless system uses multiple antennas primarily to achieve what benefit?

Accepted Answer

Increased data throughput via spatial multiplexing or diversity gain

Answer

Reduced antenna size

Answer

Elimination of impedance matching requirements

Answer

Higher operating frequency

Question 5

What is the role of a radome in an antenna system installation?

Accepted Answer

To protect the antenna from environmental conditions while minimizing RF performance degradation

Answer

To increase antenna gain through reflective surfaces

Answer

To filter out-of-band signals before they reach the feed

Answer

To ground the antenna structure for lightning protection

Question 6

In phased array radar, what physical mechanism allows the beam to be steered electronically without mechanically moving the antenna?

Accepted Answer

Progressive phase shifts applied to each array element

Answer

Variable element spacing using servomotors

Answer

Frequency changes that shift the beam via grating lobes

Answer

Amplitude tapering across the aperture