RDR - 02

Question 1

Describe the relationship between Antenna Size and Beamwidth.

Answer 1

Inversely proportional

Typically: Larger the Antenna Dimension the Narrower the Beamwidth

• Beamwidth (BW) is determined by the antenna dimensions and the frequency (or wavelength) of the transmitted signal.
• BW ≈ wavelength (λ) / Antenna size

Question 2

Define Nominal Beamwidth.

Answer 2

Nominal Beamwidth is the beam angle that contains at least half the peak power (½ power points, or – 3dB points)
of the main-lobe.

Question 3

Define Angular Resolution.

Answer 3

The ability to distinguish between 2 targets in the azimuth plane.

Question 4

Define Radar Cross Section (RCS).

Question 5

What is antenna gain and pulse per paint?

Answer 5

• Antenna Gain
  – The ability of an antenna to focus energy (Directivity).
• Pulses Per Paint
  – Number of pulses of radar energy incident upon a target.

Question 6

Define Radar Cross Section (RCS).

Answer 6

The effective area of a target that intercepts the transmitted
radar power and then scatters that power back to the radar
receiver.

Question 7

Define Effective Beamwidth.

Answer 7

• Effective Beamwidth is the beam angle that contains sufficient returned power from an object to produce a radar paint.

Question 8

describe the concept of side-lobes.

Answer 8

• A side-lobe is any area into which power is radiated other than the main-lobe.
• Side-lobes are a spillover of power that form subsidiary beams either side of the main beam.
• They can be reduced in the design stages, but never completely eliminated.

Question 9

Outline factors affecting RADAR performance.

Answer 9

• Nominal Beamwidth.
• Angular Resolution.
• Radar Cross Section (RCS).
• Effective Beamwidth