Dissertation Talk: Design of Integrated Spectral Filtering Wireless Transmitters

Presentation: Dissertation Talk: EE | May 16 | 2108 Allston Way (Berkeley Wireless Research Center), Rabaey Room

 Electrical Engineering and Computer Sciences (EECS)

A frequency-flexible radio-frequency (RF) front end has long been desired, but faces a myriad of obstacles to its realization. In recent years, the use of switching power amplifiers (PA) as part of “digital” PAs and RF Digital-to-Analog Convers (RFDAC) has become more common. The primary motivation of these RFDACs is to directly convert from digital baseband bits to RF output. This is useful in the realization of a frequency-flexible RF front end, but this is prevented by the generation of significant spectral emissions in the form of harmonics and quantization noise by RFDACs. These issues are both typically remedied with the usage of high-order fixed filters which are inherently not frequency flexible.

In this talk, I will discuss an approach to implement a frequency-flexible RFDAC-based transmitter using programmable integrated filtering to suppress spectral emissions without the use of external filters. Two filtering techniques will be discussed, as well as their requirements and limitations. Additionally, we will discuss automation of the design process using the Berkeley Analog Generator (BAG) framework. We will demonstrate two prototypes implemented in 65nm and 28nm processes achieving state of the art filtering performance at a peak power level of 25 dBm across a wide frequency range.