Tracing the Origin of the Term "Smartphone"
TL;DR: The OP was hoping to discover who was the brainchild behind the catchy name, smartphone; but as I hope to illustrate, smart phone with all its variants, had been around long before Ericsson's “Penelope” model in 1997. In fact the term smart has been often used in the world of advertising precisely because it encapsulates so many meanings in one short word: intelligence, style, elegance, class and modernity. Any possible contenders such as: PDA (Personal Digital Assistant); computer-phone; computer-functional phone, or multiuse-phone for this new generation of miniature computer phones were simply crushed by ‘smartphone’.
- Feb 1980

Google only allows previews on this publication. The following excerpt is taken from a series of snippets I managed to piece together. I suspect that Burck's ‘smart phone’ was only used in the title as I couldn't find the term within the actual article, but it hints at a forthcoming revolution in design and functionality.
For more than half a century, the office telephone was a desktop fixture as immutably prosaic as an ashtray. There was no need to think much about it: it was the phone company's property, and its function was clearly defined, its costs predictable, its longevity assured. Today, however, the plain old business phone is taking its place among the vanishing familiar certainties whose loss makes life at once more worrisome and exhilarating. No longer simply a leased appliance, the office phone is part of today's upheaval in communications "The shrinking standard of living"
Bureau of Management Consulting, Supply and Services Canada., 1980
Protel,® Inc. of Lakeland, Florida began as a pay telephone manufacturer gaining a solid reputation for leadership when we invented line-powered, smart payphones. While it has been almost two decades since our first patent, we have continued to expand our expertise in Telemetry and Management Systems to a variety of industries…
The Smartphone III comes with an operator intercept interrupt module that detects non-connection. Data capability and rate tables are programmed in by the distributors. The rate table setting is flexible and IBM PC compatible.
Seven years later...
A refined version of the product was marketed to consumers in 1994 by BellSouth under the name Simon Personal Communicator. The Simon was the first cellular device that can be properly referred to as a "smartphone", although it was not called that in 1994
source Wikipedia, Smartphone: forerunner
In 1995 a TV show called Computer Chronicles reviewed the Simon Personal Communicator and said:
This is just one example of the really cool, new, mobile computer gadgets that are out there now. Today we'll show you the newest, and the neatest, portable computing devices on this edition of the Computer Chronicles.
Video clip
Interestingly the presenter never used the term smart but he did say neatest which is a very close synonym.
The Simon Personal Communicator was the first cellular phone to include telephone and PDA (Personal Digital Assistant) features in one device but it was not until 1997, when Ericsson called its GS 88 “Penelope” a “Smart Phone” that the term was used to describe a phone with functions and features similar to a computer.
