Applying Microwave Technology in Short Range Radio Communication and Sensing Systems

Doctoral thesis, 2013

Microwave technology continues to reach new areas and applications. Microwave based sensors create the possibility to sense objects in remote and hostile envi- ronments, while miniaturization makes the merge of radios, sensors, and com- puting into new small devices possible. Bridging the communication of the last 10 meters from numerous physical devices to a global network must be done wireless. Short range radio communication technology represents the most re- alistic untethered technology at hand. Advanced digital control and processing electronics enable realization of so- phisticated functionality and sophisticated communication protocols, also in low cost small size radio nodes. The high level of integration today common for dig- ital electronics is increasingly utilized in analog electronics. The need for small low power transceivers in many new applications is mo- tivated by limited physical space and maintenance cost. The energy source for the device (usually a battery) sets the life time, the cost, and in some cases the physical dimensions of the nal product. Low power electronics enable the use of more agile energy sources and longer lifetime with smaller batteries and energy harvesting techniques. In this thesis a low power transceiver hardware and MAC protocol are pro- posed and investigated. A theory estimating noise in an envelope detector sub- ject to a blocking signal is developed and used as a knowledge base for imple- mentation of aWake-up radio. The smallWake-up radio consumes 2.3Wand is designed in 130 nm CMOS using no other external components than the carrier substrate its mounted on. A survey of recently published low-power receivers is compared with estimation of lowest power consumption with optimized re- ceiver topologies. Finally, the design of a low output-power radar interferometric sensor for industrial applications is presented together with measurements and simulations.