知名外企面试笔试题集之 RF engineer

Where is the short and the open on Smith Chart? How do you move from there if you have lossless transmission line in series?

What is the TEM mode on transmission lines?

Draw cross-sectional view of microstrip transmission line. How does the E-field look like?

How do you setup your ports in HFSS? What are different port types?

How do you make sure your HFSS simulation results are correct?

Why does the wave port in HFSS need to be wider than the microstrip transmission line?

What happens to characteristic impedance of transmission line when you play with design parameters like width, dielectric thickness, dielectric constant etc.

What do you know about differential pair signaling? What is crosstalk?

How does surface roughness affect transmission line performance?

What HFSS solution modes are there? Which one do you use and why?

For a real capacitor, what happens to the impedance when the frequency goes up?

How can you reduce loss of microstrip transmission line? You need certain impedance, you cannot change the width. What else would you do? 

When you want to model a device, say a transistor, what information can you get from I-V curves and s-parameters?

What do you know about linearization techniques for amplifiers?

How are skin depth and transmission line width important?

Find SNR of following system:

What does the following circuit look like at DC and at high frequencies?

Questions about how return current flows in microstrip transmission line, what ground path width to set and what concerns are there.