“…Striving towards less invasive therapies and inspired by scaling within the semiconductor industry, in the past years, tremendous efforts have been made in miniaturizing active implantable medical devices (AIMDs) [1], [2]. Further scaling of AIMDs, however, has always been limited by the physical constraints of the battery [3], [4]. In this regard, wireless energy transfer techniques using electromagnetic [5], [6], [7], [8], [9] and acoustic energy [10], [11], [12] have been recently proposed as alternative energy delivery solutions that can circumvent the size restriction of the battery and enable the realization of free-floating mm-sized single-chip implants.…”