The International Solid – States Circuits Conference is underway in San Francisco at the moment. Members of MCCI’s research team are in attendance to hear the latest advances in solid-state circuits and systems – on -chip. MCCI’ s Dr. Jeff Walling’s, student Zhidong  Bai will present his paper entitled “ A Multiphase Interpolating Digital Power Amplifier for TX Beamforming in 65 nm CMOS” today 2.15 pm.

The presentation will explain how future communications networks
e.g. 5G will rely heavily on beamforming, where a smart-transmitter can focus its radiation in multiple directions and smart-receivers can collect radiation from multiple directions. Increasing the number of transmitters and receivers means that all circuits must be small, use as little energy as possible and be very linear to minimize distortion.

Additionally, the more circuits that are used, the more complicated it is to control them. By using only digital inputs, it becomes easier to control many elements using only digital computing. The paper will explain how we introduce a fully digital beamforming transmitter in 65nm CMOS. This is the first demonstration of multiphase interpolation for beamforming. At its core is a switched-capacitor power amplifier, which is a circuit architecture that allows simultaneous frequency upconversion, digital-to-analog conversion and amplification using only switching transistors and capacitors in the core circuit. This enables highly-linear and energy-efficient performance in a small footprint.