Collected from interviews on both sides of the table. These are concepts, not trick questions; interviewers want to see how you reason.

Fundamentals
- Explain S-parameters to a non-RF engineer. What do S11 and S21 tell you?
- Why are transmission lines matched? What happens with an open, short or mismatched load at the end of a line?
- Quarter-wave transformer: how does it work and what is its bandwidth limitation?
- dB, dBm, dBc and dBi: when do you use each?

Receivers
- Walk through a superheterodyne receiver block diagram and explain the role of each block.
- What is the noise figure of a chain? Where should the LNA go and why?
- Image frequency: what is it and how do you reject it?
- What limits receiver dynamic range at the low and high ends?

Transmitters
- P1dB vs IP3; what does a two-tone test show?
- Why does OFDM need PA back-off, and how do you recover efficiency?
- What is ACLR and why do regulators care?

Practical
- How would you calibrate a VNA to measure a device on a PCB?
- Your measured filter is shifted lower in frequency than simulated. What might cause this? (Think dielectric constant, parasitics, etching, model setup.)
- You see a spur on the spectrum analyzer. How do you determine whether it is real?

Behavioural and project
- Describe a design you debugged. What was wrong and how did you find it?
- How do you decide between simulation and building a prototype?

Preparation tips
1. Be ready to sketch on a whiteboard: Smith chart moves, block diagrams, a simple link budget.
2. Know your own projects deeply, including what you would do differently.
3. When unsure, say how you would find out. Honest reasoning beats a confident wrong answer.