PRACTICAL TECHNIQUES TO SUPPRESS HARMONIC EMISSION IN AN IEEE 802.11A WLAN CIRCUIT

• Main Authors: Chun-Yuan Liaw, 廖俊淵
• Other Authors: The-Nan Chang
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/89656538068203947677

碩士 === 大同大學 === 通訊工程研究所 === 94 === Abstract— In this thesis, a case study relating to the third order harmonic emission from an IEEE 802.11a WLAN card is investigated. The WLAN card contains many circuit subsystems. Among them, the transceiver block, the filter block, the power amplifier block and the diplexer block are the main block under study. We carefully investigate electric performances of each block to understand if the harmonic emission may come from these blocks. In this test, each block is detached from the mainboard. We found that harmonic emission exists even through each block is individually well functioned. In addition to the block test, we also use the near field scan method to locate the nearest possible spots which may cause the harmonic emission. We found that this method is an efficient way. In our case, the emission is determined to come from the PA block as it contributes the highest radiation intensity by way of this near field test. After locating the source of emission, we can prevent them by way of shielding.