Research Of The Electromagnetic Environment And Key RF Technologies Of Wireless Home Network

The electromagnetic compatibility characters of the wireless home network constructed with WPAN (Wireless Personal Area Network) and the key RF (Radio Frequency)technologies are studied in this thesis. The scheme is brought forward under the circumstance that varieties of network technologies exist nowadays. Then the electromagnetic environment of the scheme and the LNA (low noise amplifier) & antenna technologies are researched to improve the performance of the WPAN system working in the complex electromagnetic interference environment.Firstly, the development statuses of the home network technologies are expatiated and the existing home network schemes are compared to point out that the Bluetooth is the favorite technology to construct home network in China. Then two new solutions based on Bluetooth technology are proposed, which can work better in the condition that a lot of similar networks exist. And a realization method with low cost embedded system is presented for the second solution scheme.Secondly, a statistical interference model, which is based on the total interference power level and the characters of varieties of electromagnetic interference for WPAN system, is given to analyze the average bit error rate performance of the FHSS technology under the complex electromagnetic interference environment. The results of the comparison between the analysis and the simulation indicate that the model is comparatively accurate.Thirdly, some design rules for LNA such as the minimum noise figure rule and the maximum gain rule are described, and the conflicts of them are discussed. After the impact of series inductor on the matching impedances of LNA is analyzed, a design method for LNA combining series inductor feedback with optimization simulation is studied. It not only solves the contradiction between the two rules but also saves the design time.Lastly, the characters of several types of antennas suiting for WPAN are analyzed, and the regularities that how the input impedance is affected by the geometry sizes of the IFA (inverted-F antenna) are discussed. The dimension impacts on the performance of the single band printed IFA are simulated then, based on which the novel transformed structure of the dual band printed IFA for both 2.45GHz and 5.25GHz is developed. The new structure antenna is very flexible to design and has better characters of omni-directional pattern and cross polarization character as expected. Furthermore it just can be printed on the FR-4 board directly for its compact profile, which makes it very easy to feed through microstrip line.