Design And Implement Of A WLAN Card Device Based On IEEE802.11b And IEEE802.11g Criterions

A card is designed with USB interface device based on the requirements of wireless local area network (WLAN) IEEE802.11b and IEEE802.11g criterions in this paper, and applied to the actual use of the client environment after their processing, circuit debugging and performance testing.At first, designs a system plan ,and then does the detailed design for each module of the system. RF module is a very important part of communications equipment. It enlarges the received weak signals and after the down frequency conversion processing sends them to the back-end baseband signal processing circuit. At the same time, it also does the top frequency conversion processing with the base-band signals which are then launched by the largest launch energy. Therefore, the RF circuit is the most significant part of the system.The design of matching networks. In the communication system, matching circuit plays a very important role based on transmission line theory and the maximum effect of power transmission. It directly affects the performance of the system. This paper has done to match 50 ohm match, with all test equipments to match. From a cost-saving point of view, a micro strip antenna is designed, the simulation of antenna analysis using ADS simulation software is done and the performance of the antenna is tested by the vector network analyzer (VNA).At last, the receiver AGC circuits and transmitting circuits are debugged by corresponding software, and registers initialization configuration are done, including channel configuration.According to the performance testing of LAN equipment, results shows that it fits the target requirements. The design of the card in this paper has a small size, performance stability, and supports the national security protocol standards, but also a separate AP for using with the IEEE802.11b / g criterions.