Direct Conversion of 802.11a receiver

Is it possiable to implemente of Direct conversion for 802.11a, running at 5GHz.

Any one knows this issue?

It is possible but it may be a challenge. Two 802.11a chip set manufacturers use dual conversion and low IF.

802.11a,
it depands on
1.). what process/technology you use, if CMOS, you can actually forget about designing WLAN 802.11a,
2.). what price?
3.). fully integrated or multichip?

why,"if CMOS, you can actually forget about designing WLAN 802.11a, "
there are lots of products available now!

Most of the wlan TRx products use direct-conversion
architecture today, such as Maxim's, Airoha's, broadcom's, TI's, Realtek's.., ZIF architecture is very suitable for broadband application shuch as WLAN.

By searching the IEEE JSSC you will find several papers for 5GHz 802.11a direct conversion receivers as well as the issues that they are facing like DC offset etc.

Some examples:

"A 5-GHz direct-conversion CMOS transceiver utilizing automatic frequency control for the IEEE 802.11a wireless LAN standard," Solid-State Circuits, IEEE Journal of , vol.38, no.12, pp. 2209-2220, Dec. 2003

"A 72-mW CMOS 802.11a direct conversion front-end with 3.5-dB NF and 200-kHz 1/f noise corner," Solid-State Circuits, IEEE Journal of , vol.40, no.4, pp. 970-977, April 2005

"A single-chip digitally calibrated 5.15-5.825-GHz 0.18-/spl mu/m CMOS transceiver for 802.11a wireless LAN," Solid-State Circuits, IEEE Journal of , vol.38, no.12, pp. 2221-2231, Dec. 2003