NOTE C – PATENTS

The Company’s intangible assets at March 31, 2022 include patents with estimated remaining economic useful lives ranging from 1 to 17.25 years (see Note G[2] hereof). For all periods presented, all of the Company’s patents were subject to amortization. The gross carrying amounts and accumulated amortization related to acquired intangible assets as of March 31, 2022 and December 31, 2021 were as follows:

Amortization expense for the three months ended March 31, 2022 and 2021 was $75,000 and $74,000, respectively. Future amortization of intangible assets, net is as follows:

All of the patents within the Cox Patent Portfolio expired in September 2021 except for two patents which expire in July 2023 and November 2023. The expiration dates of patents within the Company’s M2M/IoT Patent Portfolio range from September 2033 to May 2034. The expiration dates within the Company’s HFT Patent Portfolio range from October 31, 2039 to November 1, 2039. All of the patents within the Company’s Mirror Worlds Patent Portfolio expired. The Company’s Remote Power Patent expired on March 7, 2020.