I have a question related to 802.11n wi-fi antenna. What actually do we mean by 1T1R mode for Wi-Fi?

As per wiki, the same channel is used for Tx & Rx:

In 1T1R mode, do we need a separate antenna for both transmission and reception?


The same antenna can be and is used for both TX and RX. However, in MIMO, SIMO and MOSI systems, you can have multiple RX antennas for the same TX, multiple TX to RX antennas and basically any number of combinations. Usually in MIMO it's for example 3x3 (3TX and 3RX).

  • \$\begingroup\$ thanks .... if i have to transmitt a 1K of file to remote wifi node .... now if i have a 2x2 antenna for transmission then what happens in this case ... does it means that 0.5Kbye of file will be transmitted by one antenna & another 0.5Kbyte will be transmitted by another antenna at same time...? is there some good tutorial to explain this concept ..? ........ Also how does micro-controller will be connected to two antennas in this case ... does these type of controllers have two pins for transmission to two antennas & two pins for reception from two antennas in these case ? \$\endgroup\$ – Allan Mar 23 '13 at 15:35
  • \$\begingroup\$ please suggest on above points. \$\endgroup\$ – Allan Mar 23 '13 at 15:37
  • 1
    \$\begingroup\$ @Allan: The upper layers have no idea this is happening. This occurs usually in the RF layer (layer 1), with perhaps some involvement in layer 2.It is transparent to you. In reality, transmitting 1kB file will rarely benefit. MIMO is very common in 802.11n and 802.11ac because they can deliver higher reliability and throughput using the antenna diveristy. THis is needed for many Mbps. Microcontrollers cannot sustain more than a few Mbps, and usually because antenna diveristy takes up more space and is more expensive. It is therefore unlikely to be available except for application processors. \$\endgroup\$ – Gustavo Litovsky Mar 23 '13 at 15:47
  • \$\begingroup\$ @ Gustavo: thanks ... I have a controller Rt3052 which supports 802.11n .. but i will be using it in 1x1 mode .. as it is my first project. As it will be my first design for wi-fi i have searhed a lot on google & found this I.c RF5745 for impedance matching of 50 ohm. ..... rfmd.com/CS/Documents/RF5745DS.pdf.... antenna i will be using is ..... inpaq.com.tw/Specification/RF/… ...... now if i use following IC RF5745 do i need some balun to connect antenna to microcontroller .. ti.com/lit/an/swra317/swra317.pdf \$\endgroup\$ – Allan Mar 23 '13 at 16:16
  • \$\begingroup\$ any suggestion will be helpful .. to come to some conclusion for antenna design. \$\endgroup\$ – Allan Mar 23 '13 at 16:18

Not the answer you're looking for? Browse other questions tagged or ask your own question.