Receiver performance in radar: A radar receiver front end is designed for very high sensitivity and a low noise figure. Is this statement correct?

Introduction:
Radar systems must detect extremely weak echoes returned from distant or small targets. Consequently, the receiver front end is engineered to achieve high sensitivity and low noise figure so that signal-to-noise ratio (SNR) after detection exceeds the threshold needed for reliable detection.

Given Data / Assumptions:

• Standard radar front end includes a low-noise amplifier (LNA) or mixer-first architecture with RF filtering and protection.
• Noise figure directly impacts minimum detectable signal (MDS).
• Targets may be far away or low radar-cross-section, leading to tiny echoes.

Concept / Approach:

From the radiolocation equation, received power falls with R^4 for monostatic radar. Improving the receiver noise figure reduces the effective noise floor k T B F, where F is the noise factor, thereby lowering the MDS. High sensitivity is realized by combining low noise figure, adequate gain distribution, appropriate bandwidth, and matched filtering in the IF/digital domain.

Step-by-Step Solution:

Verification / Alternative check:

Radar receiver specifications universally list low NF LNAs (often < 2 dB in many bands) to meet detection range targets; cold LNAs are used in specialty systems but are not strictly required to validate the statement.

Why Other Options Are Wrong:

• False or conditional versions limit applicability; all radar types benefit from low NF and high sensitivity.
• Cryogenic antenna is not required, though cryogenic LNAs may be used in niche systems.

Common Pitfalls:

Overemphasizing gain without managing noise figure and bandwidth; excessive bandwidth increases noise power and degrades sensitivity.

Final Answer:

True