Tunable Filter Miniaturization Research And Design Of RF Front-end In Wireless Sensor Network

Computer network technology stand by Internet is a great achievement of computer science in twenty centuries, it brings to our life great changes. However in the present, even the network is more powerful, the network world is richer, eventually it is virtual, and it is at a distance of our real life. In the network world, it is hard to perceive the real world, a lot of things are impossible, The Times calls for a new network technology. Wireless sensor network is a new network technology in this background. It is include sensors, low power consumption, communication and MEMS and so on. We can foresee, in the near future, wireless sensor network will give our way of life brought a revolutionary changes.Wireless sensor node includes data acquisition unit, data processing unit and data transmission unit, the data transmission units are mainly RF circuits, and its core devices except for sending and receiving antenna, a high performance of filters are presented, used for anti-jamming and filter. RF filter research and design for wireless sensor network has the positive sense.Wireless sensor network receiver system send command to the center frequency, through the control performance adjust module adjust the radio frequency response of electronic tunable filter modules. Filter modules are consist of automatic tuning electronic filter, the problems need to be solved is the short period of electronic tuned filter, the period is less than 100 us, to ensure the good frequency variable speed. Automatic resonance function adjust the sending of instruction module performance tuning filter of electronic adjust itself coupling coefficient and the resonant frequency to realize the ideal performance of the wireless sensor network receiver system.The filter design should meet the design requirements of the target, and it is also need to consider the factors of special environmental requirements, comprehensive performance target and environmental requirements to accept or reject, that it is capable to design the filter applied to practical engineering. Because of the wireless sensor network node environment complexity, large numbers, the limitation of the power supply, the short timeliness, and many other factors, the filter design need to meet the requirement of small size, light weight, low cost, fast tuning speed (micro strip structure of the filter is a very good choice, but insertion loss value is partial big), and because the filter used to filter out the interference of the antenna noise signal as primary filter, the insertion loss could not be too big, so there are difficulties and challenges to design the filter.This paper designs a micro strip comb line electric tunable filters, and the characters of this structure are compact, fast tuning speed, low cost, and meet the requirements of wireless sensor network node design.