CAD Cheat Sheet 2026

The 30 highest-yield CAD facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. On a Smith Chart, where is a perfect impedance match (Z = Z0) located? → At the center of the chart
2. What is the recommended frequency for reviewing and updating antenna designer measurement techniques protocols? → Monitoring outcomes through regular data collection and trend analysis
3. Which advanced antenna technology is used in 5G networks for beamforming? → Massive MIMO
4. What is the most common mistake professionals make when implementing antenna designer design and simulation strategies? → Developing contingency plans for high-probability risk scenarios
5. A new regulation impacts antenna designer measurement techniques procedures. What should a CAD professional do first? → Ensuring compliance with current regulatory requirements and standards
6. Under FCC rules, which document must an antenna tower owner file to notify the FAA of a proposed new structure? → FAA Form 7460-1 (Notice of Proposed Construction)
7. In the context of antenna designer, which principle most directly governs antenna designer advanced antenna concepts practices? → Applying evidence-based methodologies with peer-reviewed support
8. FCC Part 15 regulations limit unintentional radiator emissions primarily to prevent what? → Interference with licensed radio services
9. What is the significance of return loss in antenna measurement? → Higher return loss indicates better impedance matching
10. A choke balun placed at the feed point of a dipole antenna primarily serves what function? → Preventing RF current from flowing on the outer shield of the coaxial feed line
11. Why is time-domain reflectometry (TDR) used in antenna measurements? → Detects faults in transmission lines
12. How does a series feed network for a linear array differ from a corporate feed network? → Series feeds use less transmission line but exhibit beam squint with frequency change
13. In phased array radar, what physical mechanism allows the beam to be steered electronically without mechanically moving the antenna? → Progressive phase shifts applied to each array element
14. What is the input impedance of a lossless transmission line terminated in a short circuit (Z_L = 0) and exactly λ/4 long? → Infinite (open circuit)
15. Which transmission line type uses two parallel conductors separated by a dielectric and is classified as a balanced line? → Twin-lead (parallel wire) line
16. Which ITU radio regulation document allocates the radio frequency spectrum internationally and is binding on member states? → ITU Radio Regulations
17. What happens to the electrical length of a transmission line when the operating frequency is doubled? → The electrical length is doubled
18. What is the main benefit of a fractal antenna? → Operates efficiently over multiple frequency bands
19. What is the function of a diplexer in an antenna system? → To combine or separate two frequency bands through a single antenna port
20. What is the standard characteristic impedance of coaxial cable used in most RF antenna systems? → 50Ω
21. In a cellular base station, what is the primary purpose of using a sector antenna instead of an omnidirectional antenna? → To concentrate radiated power into specific angular regions for increased capacity
22. A quarter-wave transformer is used to match a 50Ω source to a 200Ω load. What characteristic impedance must the transformer section have? → 100Ω
23. What standard body maintains the CISPR standards used globally for measuring radio interference from electronic equipment? → IEC (International Electrotechnical Commission)
24. In a T-junction power divider, what is the primary disadvantage compared to a Wilkinson divider? → T-junctions provide no isolation between output ports
25. Which of the following best describes the radiation pattern of an isotropic antenna? → Isotropic
26. What is the most common mistake professionals make when implementing antenna designer advanced antenna concepts strategies? → Developing contingency plans for high-probability risk scenarios
27. What is the main advantage of using a tapered transmission line section in an antenna feed network? → To achieve gradual impedance transformation with low reflections over a wide bandwidth
28. Which scenario would require a antenna designer professional to escalate a antenna designer design and simulation concern? → Creating feedback mechanisms that encourage continuous improvement
29. Which type of antenna is commonly used for satellite communications? → Parabolic reflector antenna
30. What is the primary goal of antenna design and simulation? → Optimize antenna performance before fabrication