Asus ROG Phone II design story: here are the many prototypes that guided the design

Asus set out to create the best smartphone for hardcore gamers and Android power users. The ROG Phone II went through several iterations until the engineers found the optimal design – this is a look at the designs that were tried and rejected in the process.

This phone targets people who game 16 hours a week or more, as well as those who want a flagship with exclusive features. Asus says that these groups of consumers want the biggest screen possible and don’t mind a heavy phone. The only design limitation was that the phone had to be no more than 78mm wide as consumer research showed this was the maximum for one-handed use.

With that in mind, the first parameters to nail down were the screen size and battery capacity. Asus tried everything from 6.59” to 6.75” and 5,000mAh to 7,000mAh in different combinations. Weight obviously depends on the size and battery, the thickness is affected too.



Six prototypes with different screen and battery combinations

Ultimately, the team settled on a 6.59” screen and a 6,000mAh battery (9.5mm thick, 240g in weight). That’s thinner and lighter than most prototypes, though still thicker and heavier than almost all flagships out there.

All gaming hardware, even PC components that go inside the case, have to look the part. That rings even truer for a premium phone. Here are eight different designs for the back that were tried out.



Different designs for the back panel

Asus played with different materials too. Note that for the sake of superior cooling, the second generation ROG Phone lost the water resistance. The trade-off is a structure of internal and external vents that help carry away the heat.



Trying out various materials for the back

Many flagships have vapor chamber cooling and heat pipes, but most of them are sealed up, which traps the heat inside. Just having a vapor chamber isn't enough for good cooling as we found in our exploration of thermal throttling.



A diagram of the cooling setup

The Asus ROG Phone II has a rich selection of first-party accessories for better gaming or desktop experience. If you carry just the phone, you still get a pair of extra controls – the AirTrigger II shoulder buttons. It took several iterations until the perfect indentation depth, pattern and texture were found.

These have to feel like real buttons when in use (the two optimized haptic feedback motors help in this regard), but the shoulder buttons should keep out of the way when holding the phone vertically.



Iterations of the AirTrigger II design

When gaming, the phone is held horizontally, so Asus had to position the Wi-Fi and 4G antennas differently to ensure optimal bandwidth and latency (and avoid potential death grip situations). Even the front-facing camera is placed with landscape orientation in mind, in case you want to include your mug on the screen as you do commentary during a gaming session.



Antenna placement was optimized for landscape use

As accessories are a key part of the experience, they were developed alongside the phone itself. The new TwinView Dock II had to be designed carefully to achieve a comfortable weight balance (it uses its 5,000mAh battery as a counterweight).



TwinView Dock II prototypes

We only got to spend a few hours with the Asus ROG Phone II, but our first impressions are very positive – we appreciate the handset’s potential both as a gaming phone and as an all-out flagship.