Which of the following statements about antenna classification is correct ()? (Select 2 Answers)

Antennas can be categorized based on various technical parameters. When classified by directivity, antennas are divided into omnidirectional antennas (radiating energy equally in all horizontal directions) and directional antennas (focusing power in specific directions). When classified by physical structure or shape, they include linear antennas, planar antennas, and surface antennas. Options C and D swap their classification criteria: short-wave, ultra-short-wave, and microwave represent working frequency bands, whereas communication, television, and radar represent practical applications or purposes. Thus, options A and B are the two correct statements regarding antenna classification principles in WLAN and RF engineering contexts.

Option C: Short-wave, ultra-short-wave, and microwave classify antennas by their working frequency band, not by their engineering purpose.
Option D: Communication, TV, and radar describe classification by antenna application/purpose, not by working frequency band.

1. Huawei Technologies Co., Ltd., WLAN Network Planning and Design Guide, "RF Principles and Antenna Basics," Section 2.1 Antenna Classification.

2. Academic Review: Balanis, C. A., Antenna Theory: Analysis and Design, 4th ed., Wiley, Chapter 1: "Antenna Fundamentals and Classification Criteria."