| Project Detail |
While most analog functions have been taken over by their digital counterparts, radio receivers today are complex analog electronic circuits. They include amplifier circuits to provide amplification of the weak antenna signals. Ideally the amplifiers provide linear gain, but unfortunately the amplifiers exploiting transistors are inherently nonlinear, causing fundamental problems if large unwanted signals are received simultaneously with weak desired signals. This is why a radio receiver is a complex combination of many analog circuits: filters, mixers and amplifiers are placed between the antenna and the analog-to-digital converter (ADC), making receivers bulky, expensive and consume a lot of energy. The breakthrough concept of this program is to completely refrain from active linear amplifiers and thus have no active linear gain in a receiver. This way we avoid the fundamental problems in amplifiers and we minimize the analog hardware between the antenna and ADC, thus drastically simplifying the radio architecture. This program aims at connecting the ADC to the antenna, with just a separation by a so-called “N-path filter”. As pioneered amongst others by myself, N-path filters are simple structures without amplification and have recently become popular for wireless applications after being “forgotten” for many decades. Research work will focus on: 1) an N-path filter antenna interface, with extreme selectivity; 2) an ultra-low-noise ADC being able to convert the unamplified antenna signal; 3) a digital reflector to reflect unwanted signals arriving at the antenna; 4) precise timing circuits with far-beyond state-of-the-art timing accuracy to clock the N-path filter. I will focus on two different application areas: high-end receivers for high data rates in a crowded spectrum and ultra-low power receivers for (battery-less) sensor networks. My goal is to design fully integrated receivers on a chip, without the bulky and expensive external components needed today. |
