Microwaves for communication – Key advantage What is the principal advantage of using microwave frequencies for communication links, compared with lower-frequency radio bands?

Introduction / Context:
Microwave spectrum allocations provide wide contiguous bandwidths, which is the central driver for high-capacity links such as satellite backhaul, point-to-point radios, and modern WLANs. Bandwidth is the currency of data rate, per Shannon’s capacity relation and practical modulation schemes.

Given Data / Assumptions:

• Comparing microwaves (roughly 1–30 GHz) with lower-frequency HF/VHF bands.
• Considering typical regulatory allocations and available channel widths.
• Assuming appropriate link budget and line-of-sight where required.

Concept / Approach:

Wider bandwidth directly supports higher symbol rates and therefore higher throughput using QAM/OFDM. While microwaves have higher free-space loss and may suffer rain fade, the sheer bandwidth availability outweighs these disadvantages for many systems, especially with high-gain antennas and spatial reuse (narrow beams reduce interference and enable frequency reuse).

Step-by-Step Solution:

Verification / Alternative check:

Real systems: Wi-Fi at 2.4/5/6 GHz, E-band (70/80 GHz) backhaul offering multi-Gb/s, and Ku/Ka satellite links exemplify bandwidth-driven capacity at microwaves.

Why Other Options Are Wrong:

Options C and D confuse power with advantage; E is false because atmospheric effects can be significant at some microwave bands; B contradicts the capacity objective.

Common Pitfalls:

Assuming path loss alone dictates feasibility; in practice, high-gain dishes and narrow beams make microwave links practical and spectrum-efficient.

Final Answer:

large available bandwidth enabling high data rates.