Articles
Application Note: An Introduction To High Performance Wi-Fi Filters
April 1, 2005
By Anatech Electronics Inc.
A filter is a device meant to suppress unwanted signals, or limit the passage of a specific band, while rejecting signals outside of that band. Wi-Fi filters are generally bandpass filters or diplexers set to tune at specific assigned frequency for the WI-Fi, which use the 802.11a or 802.11b standard. Wi-Fi networks operate in the unlicensed 2.4 and 5 GHz radio bands, with an 11 Mbps (802.11b) or 54 Mbps (802.11a) data rate.
Anatech Electronics' Wi-Fi filters for base stations use the cavity-type filter for low loss. The approximation used is that of a quasi-elliptic, which can achieve an improved passband flatness with very steep stopband performance. Extra poles are being introduced in order to achieve that steep passband to stopband transition, as in the figures below.
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