Design of sensors with limitations in areas up to a few mm2, ultra low-power, capable of customization into aWireless Sensor Network (WSN) for monitoring applications, represents one of the most challenging and discussed issues in electronic sensor developmentsocieties. There have been several attempts recently, in development of the common wireless sensor components. Efforts have been concentrated on area and power minimization, reliability and security. Recently, examples in development of a System on Chip (SoC) as Application Specified Integrated Circuit (ASIC) capable of measurement and transmission to a Wireless Sensor Network (WSN) has been reported.Design of such a sensor is quite challenging; partially because of the demanding multi discipline approach involving µ/nano-Electronic, Micro Electro Mechanical System (MEMS), Radio Frequency Micro Electro Mechanical System (RFMEMS), Radio Frequency (RF) transmission dexterity. Another obstacle on the path is compatibility to a diversity of standards and regulations in different countries and satisfying various authorities and disciplines.Unanswered paradigm question would be whether it is possible or necessary to design a general purpose Wireless Sensor Node on Chip (SNoC) covering the entire aspect of WSN interests. Probably there will never be such a sensor satisfying requirements of all demands. In this thesis one typical sensor node design as SoC will be suggested and the advantages and drawbacks discussed. More precise; RF communication and RFMEMS possibilities and limitations will be discussed. To prohibit confusion between the term Wireless Sensor Network and Wireless Sensor Node, we will consequently address SNoC as aWireless Sensor Node in this thesis.