Katherine D. Cappaert

Katherine D. Cappaert is a patent litigation partner at Steptoe, leveraging her background as a mechanical engineer to represent clients in complex intellectual property disputes. Her practice encompasses a broad spectrum of technologies, including solar manufacturing, semiconductors, consumer electronics and smartphones, fiber optics, cloud and distributed computing systems, seismic surveying operations, subsea oil exploration, automotive technology, pharmaceuticals, and various electrical, mechanical, and geophysical fields.

While Ms. Cappaert's two tracked appearances list her as counsel for the plaintiff, Terumo BCT, Inc., in Terumo BCT, Inc. v. Haemonetics Corp., court records for the corresponding litigation (e.g., Haemonetics Corp. v. Terumo BCT, Inc., 1:25-cv-01409) identify Terumo BCT, Inc. as the defendant, with Ms. Cappaert acting as defense counsel. This reflects her broader practice, where she works with both plaintiffs and defendants in patent and trade secret litigation, including Section 337 investigations before the US International Trade Commission (ITC). Notably, she successfully represented respondents Leedarson Lighting Co., Ltd. and Leedarson America, Inc. in two ITC investigations involving LED and IoT technologies. She also achieved a favorable result for a solar manufacturing company in multi-venue litigation across the ITC, PTAB, and district court.

Ms. Cappaert possesses significant experience with patent validity challenges before the Patent Trial and Appeal Board (PTAB), having been recognized by the PTAB Bar Association as a "Top 50 Woman in PTAB Trials" in 2019, 2021, and 2025. She actively participates in IPR and PGR proceedings, including those between Terumo BCT and Haemonetics Corporation, and has published on best practices and developments at the PTAB.

She is admitted to practice in the District of Columbia.