Software is nothing without the hardware to run it on, and that hardware needs to be rock-solid. Today’s spotlight interview is with Robin Chang, who is responsible for all the hardware nuts and bolts — or, more precisely, the wires and antennas. And he might have built one of your old favorite phones, too. 

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Thanks for chatting with me, Robin. You can’t avoid the startup cliche: Everyone does a billion different things, even if they have a specific domain they work on. To start, can you tell our readers what your title is and what it means you normally work on?

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I am the Principal RF Engineer, and that means I’m an engineer who focuses on RF wireless applications. That means I handle the circuitry for wireless transmission and connectivity of any kind, and features including 5G and cellular to Bluetooth, Wi-Fi, NFC, and UWB. Some new technologies in that vein might also be included. On top of that, I also handle most of our hardware electronics circuitry design. 

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That’s a big responsibility!

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Yeah. We are a small company, and hardware is the baseline for supporting our software development. There are lots of external partners we need to work with, too. So it’s a very large responsibility, but still an acceptable workload to manage, even with design and planning and validation and testing and performance analysis and manufacturing. I like this position!

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That does sound like fun. On the side, I’ve been trying to learn a bit of circuit design, and I’ve come to realize how different digital and analog circuit design is — one’s easy, and the other is really, really hard. Analog circuits are more like an art than just a science, and that’s a lot of the work that you do. 

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Yeah! Analog is more about continuous signals. For our applications, that usually means input and output from controllers, and RF is analog. We design what we want to get input to the controller or processor and then what we expect the controller or processor to push out to other devices or functions. 

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You’ve been doing circuit design for 25 years now across so many recognizable products. You worked on early CDMA stuff, and you worked for big-name companies like Palm, Nokia, and Intel. 

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Actually, my favorite job to remember is at Motorola. I joined Motorola instead of Samsung when I graduated from university in Korea. I had a 100% chance to join Samsung, but I wanted to experience more US culture at Motorola, and I liked Motorola’s motto: “Respect for people, uncompromising integrity.” 

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Even though Samsung paid more for new, fresh engineers, I liked Motorola’s culture and focus better. But, I think that Motorola failed to catch up to changes in technology. It focused on hardware robustness and user experience. They looked at hardware as hardware, not software or applications. But I liked Motorola the most as a part of my experience. 

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What products did you work on at Motorola? Did you get to work on the original Razr?

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At the time, Motorola was a very big company, and they had three tiers: High tier, medium, and low tier. I worked in the mid tier in Korea in another form factor that was based on Razr. So I can say it was part of the Razr program. After that, when I moved to the US, I worked on the Krzr K1m—

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My sister had one of those!

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Yeah! That product wasn’t high tier, more mass market/high production. I think we sold more than ten million in 2-3 years. I was on both concept and manufacturing support for that. 

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What did you work on at Palm? Did you work on the Palm Pre?

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No. I joined in like 2007, but I did work on Palm smartphones running the latest Qualcomm chip at the time — very similar. Even from Motorola, I worked with Qualcomm forever, except at Intel. I worked on a wearable there that used an Intel chipset. 

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Since you’ve seen and engineered for every new cellular technology first-hand, from CDMA through 5G NR standards, I’m really curious to hear what you think of millimeter-wave 5G and whether it has a real future in phones. 

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In my personal opinion, I don’t think we need it. The high speeds it offers don’t really fit any consumer use case right now — 5G FR1 [Editor’s note: 5G on Sub-6 GHz bands] and even high-end 4G LTE+ performance is enough. In the future, there may be other use cases, like autonomous driving or other unmanned vehicles, that need really large data communication to justify it. Now, it isn’t really necessary for users. 

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With antenna designs now being parts of the phone that customers see and touch, integrated into the metal frame and things like that, that must mean you do more than purely electrical CAD work — there has to be some connection with the design guys, too, making sure that the shapes are correct and perform right. Sort of analog circuit art-as-science-as-design-art?

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Well, it’s still really a science, and people have been working on these kinds of antenna concepts for more than forty years now. And in a lot of ways, it’s almost the same as it was twenty years ago. But back then, we would just use two antennas — top and bottom, high frequency and low frequency. But now phones need at least nine or ten antennas! 

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Saga has ten antennas. 4x4 MIMO needs at least four antennas just for cellular, plus different antennas for different frequency groups and more for overlapping and independent operation. There’s Wi-Fi MIMO, GPS, NFC. And UWB needs three antennas for directionality. Even wireless charging — that’s an antenna. Some antennas like that are already defined very well; you just sort of size them and put them in. But most of them are not. And if you need mmWave, it’s a very different frequency range, and you need at least two more antennas for that. Some suppliers, like Qualcomm, sell a module, and that antenna can be smaller and easier to design. 

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For example, let’s say you are designing an antenna for 100MHz like a walkie-talkie or PTT. The signal goes very far because it is a low frequency, but for good performance you need a pole antenna that’s a couple meters to meet the necessary quarter wavelength antenna size and receive a signal well. But for mmWave’s 20-40 GHz, you only need a 2-3 mm antenna to reach the same quarter wavelength, though you need to give it clearance for radiating power from other metals. 

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It’s not more of a science than it used to be, but there is a lot of simulation and testing you have to do for how all antennas perform — radiating patterns, isolation, clearance, interference between antennas, optimal locations, and sizes. It’s… a lot of engineering work. 

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Another engineer here at OSOM, Alessio, brought up a new technology recently, NFMI, which uses magnetic fields to send data over short distances. What do you think about that?

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It’s a concept like NFC, but it’s not RF. That idea is emerging for things like earbuds. Some earbuds are already using it to communicate and sync between buds, so either can be the primary or secondary bud. It’s kind of cool, but I don’t know if it’s really required for consumers — you can solve the same problems with just Bluetooth, though NFMI may reduce latency more. But it’s more of a marketing point than anything else; the latency difference isn’t that big. 

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This might be a dumb question, but I think it’s a fun one given your experience: If you could put cellular connectivity into any device out there that doesn’t already have it, what would it be?

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It might not seem necessary for my work, but as an engineer, I always think about accessibility and disability first — not just people but animals too! Monitoring people with disabilities indoors or applying wearable sensors for disability applications. A necklace that can help those with communication difficulties speak. A wearable for dogs that interprets their sounds, indoor tracking movements, and other physical characteristics to tell you if they need to be walked or are in distress. 

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Those are great ideas! 

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So, what was your favorite thing to work on for Saga?

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It’s been a while since the electrical engineering work for that. I think my favorite thing isn’t a feature, it was getting to work with new people like our PM, Alessio, and the operations team. Our fun leaders like our CEO Jason and Dave Evans. And, of course, Nick Franco. Our hardware partners have been great, too, especially our manufacturing partners — they did very good, very proactive work, and I have a lot of confidence in them. 

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One last question: What is your favorite feature on Saga?

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[Laughs] I don’t really have special requirements in my devices, and I always use the things that I develop — at Motorola, I used my Motorola phones; at Palm and Nokia it was the same. There was no Intel phone, so I used a Samsung then. And in our phone, my favorite thing is the fingerprint sensor!

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That is a surprisingly popular choice!

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Wireless charging, too. When I used to work on phones, it wasn’t as common or reliable, but I like using it on Saga. 

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Thanks for taking the time here, Robin. I always love getting to nerd out on the engineering details the team works on.