Real Transcripts 18 min read
Real Interview Transcript: DRDO RAC Scientist "B" (ECE - Radar & EW) New Delhi
Candidate profile: B.Tech ECE, GATE EC Rank 210. Interview held at RAC complex, Lucknow Road, Timarpur, Delhi.
#DRDO Transcript#ECE#Radar#Microwave#Scientist B
In-Depth Interview Questions & Model Solutions
Q1Panel Expert (Microwave): "Why do rectangular waveguides not support TEM (Transverse Electromagnetic) waves?"
Candidate Answer: "Sir, a TEM wave requires both axial electric field Ez = 0 and axial magnetic field Hz = 0. By Maxwell’s equations, in a hollow single-conductor waveguide, a non-zero TEM wave would require electric field lines to start and terminate on the same conducting boundary without enclosing any enclosed net current, which violates Gauss’s law unless the field is identically zero everywhere. Therefore, hollow metallic waveguides only support TE (Ez = 0, Hz != 0) and TM (Hz = 0, Ez != 0) modes."
Technical Panel Interview Strategy Tips
- Review electromagnetic wave propagation in rectangular and circular waveguides (cutoff frequencies fc = c/2 * sqrt((m/a)² + (n/b)²)).
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