28.3 A 606μW mm-Scale Bluetooth Low-Energy Transmitter Using Co-Designed 3.5×3.5mm 2 Loop Antenna and Transformer-Boost Power Oscillator

Wireless communication has been a limiting factor for achieving millimeter-sized wireless sensor nodes because of the high power consumption, large antenna size and off-chip components typically required. Several mm-scale radios have been proposed [1-3]; however, all use proprietary communication protocols, which afford their designers more flexibility to address the above challenges. For interoperability and ubiquitous adoption, it is important that mm-scale radios use standard protocols, such as Bluetooth Low Energy (BLE). However, implementing a BLE-compliant radio in a mm-scale form factor poses significant additional challenges. These include the requirements for center frequency deviation $( 3$mW [4- 5]. A 0.5mW BLE transmitter was achieved by relaxing these requirements, but suffered from high phase noise due to its low-power ring oscillator [6].