Summary: Lots of systems questions for a position seeking subsystem hardware design. One interviewer seemed to be seeking proprietary information. They did not honor telling you results within two weeks, as they emphasized during the in-person interview and as shown on the website. Someone hung up on me after I introduced myself when I called to inquire about the status about a month after the interview. They took a lot of pictures of what I wrote on the whiteboards.

They called me about a month after I applied to the position. It was very difficult to hear them over the phone, but the questions were relevant to my background, and I could hear them well enough. They told me they were looking for someone who was more subsystems and very hardware oriented, which matched my background, although they asked a lot more systems questions during the in-person interview.

Setting up the in-person interview took almost a month. A person from another country tried arranging this. I ultimately settled on a day that I was not very available for, and just made it happen at my own hassle and expense (I was local but did have to struggle with time off from work).

The first part of the interview was with an HR person over the phone, and they were about 10 minutes late to the call. It wasn't from the person listed in the email. I was placed in a room that was scheduled for another meeting, so the people in that meeting asked me to leave the room, but luckily it didn't interrupt the first call. There were just a few behavioral questions and expected compensation. She sounded very skeptical when I gave her numbers, which were only a little bit higher than what I am currently making.

The actual part of the interview was separated by three technical interviews with individuals and a lunch with another.

The first in-person interview was with the hiring manager. They asked questions about S-parameters and their transforms, transceiver design including noise figure and linearity, then questions about transmission lines, matching networks, and using a Smith chart. The first interviewer wanted to revisit our first interview after lunch, but this time we covered switched power converters, Nyquist stability contour, op-amp configurations and deriving their transfer function (buffer, subtractor, adder, inverting, non-inverting, differentiator, integrator, active filters with gain). We also talked about a few of the textbooks I had read.

The second in-person interview was during lunchtime. The conversation was mostly very casual, discussing some hobbies and a little about each other's professional/technical background. The food was good, and the person was pleasant to talk to.

The third in-person interview was more about PCB layout and asked me about materials and their parameters such as dielectric constant and loss tangent. They asked about the process flow of the layout and rough timelines, and the typical number of metal layers, how to choose a stack-up, and a few fabrication challenges/considerations such as aspect ratio. I told them I couldn't tell them exact materials I was using in fear of it being proprietary, but was okay with giving examples of well-known or common ones I've seen in textbooks. I provided an example stack-up and what my thoughts were on some design tradeoffs. We talked about the tools we were familiar with and some of their features.

The last in-person interview asked similar questions to the first and third. I don't think English was their native language, and they sounded very skeptical about some of my answers. When I told them I was worried about proprietary information (they were seeking very specific materials, band and channel frequencies, and part numbers—no, I'm not giving that), they responded with "How could you not know? You said you designed it." Yes, I did, but it belonged to the company I work for. They had me do the same cascade of noise figure. After I got past the first LNA, they wanted me to continue. I told them it was going to be dominated by the NF in the front and the number wouldn't change much, showing the Friis formula, but they insisted that I continue (it didn't change much, maybe 0.2 dB). They scoffed at some of the gain numbers I provided. They were also very disturbed by one of the filters in my design. These were confident answers, as I've seen these at my current job and they were straight from the textbook anyway.

They told me I'd hear results within two weeks. I sent a thank you email, which received no reply. I didn't hear back after two weeks. I tried calling and emailing after three weeks with no answer, as I had read on some Glassdoor reviews might be the case. On the fourth week, I called and someone answered, but they hung up on me (I wouldn't accept an offer after that). A few days later, they sent an email saying they'd reach out to the team to see what was going on, and that was the last I heard from them (maybe 2+ months ago?). The position has already been taken down from the website. Please do not promise results within two weeks and hang up on me. It is okay to tell me that I did not get an offer—nothing bad will happen.

Design a transceiver.

Add the gain, noise figure, and linearity of each part.