Topic: Microwave Engineering
Relationship between doppler frequency shifts of two radars A and B having 0.1 foot and 0.05 foot wavelengths, approaching the target at 1000 feet per second and 2000 feet per second rate respectively, will be
- A. Doppler frequency shift of radar A will be one-fourth of doppler frequency shift of radar B
- B. Doppler frequency shift of radar A will be one-half of doppler frequency shift of radar B
- C. Doppler frequency shift of radar A will be double of doppler frequency shift of radar B
- D. Doppler frequency shifts of radar A and radar B will be same
Answer: A. Doppler frequency shift of radar A will be one-fourth of doppler frequency shift of radar B
Explanation: Doppler shift for Radar A: $f_{D,A} = \frac{2v_{A}}{\lambda_{A}} = \frac{2 \times 1000}{0.1} = 2 \times 10^4$ Hz. Doppler shift for Radar B: $f_{D,B} = \frac{2v_{B}}{\lambda_{B}} = \frac{2 \times 2000}{0.05} = 8 \times 10^4$ Hz. Therefore, the Doppler shift of Radar A is one-fourth of the Doppler shift of Radar B.