The big picture: Apple's 2020 iPhones will reportedly feature a redesign that brings back the metal frame structure made popular on the iPhone 4 / iPhone SE and recently brought back on the iPad. Is this a good idea or should Apple look elsewhere for a redesign?

Renowned Apple analyst Ming-Chi Kuo said in a recent research note that the new phones will feature "a more complex segmentation design, new trenching and injection molding procedures, and sapphire or glass cover assembly to protect the trench injection molding structure" around the perimeter of the device.

Kuo believes the changes will make it easier for the phone's internal antennas to send and receive high-frequency transmissions. That could be important considering Apple is expected to support 5G in all of its iPhones next year courtesy of Qualcomm hardware. Apple won't use its own 5G hardware until at least 2022, we're told, and will likely test the tech in the Apple Watch first.

The glass or sapphire will simply protect the injection molded structure along the groove.

The redesign could have a substantial impact on Apple's cost of components. The metal frame and glass case price could shoot up as much as 50 percent each, Kuo notes.

In an earlier note, Kuo said he also believes Apple will introduce new sizes for its 2020 iPhones including a 5.4-inch model, another with a 6.1-inch screen and a third with a 6.7-inch display.

Masthead credit: iPhone by Hadrian. iPhone 4 by George Dolgikh