Qualcomm Inc. and Motorola Inc. agreed on Tuesday to settle a series of patent suits that have embroiled the companies in litigation for the past three years.

Litigation between the two companies began in 1997 when Motorola, of Schaumburg, Ill., claimed Qualcomm was infringing design patents and trade dress in the manufacture of its “Q” phone, a wireless folding telephone in a clamshell shape. Motorola sells a similar phone.