A question of transceiver

[OMEsystem]

I have a question of the slides in this link.
Pleae go to page 41.

**broken link removed**

I can't realize what's the relation between "small antenna" and "LNA sensitivity", and
the realation between "small antenna" and "IIP3".

Any recommendation?

Thanks,

 

[biff44]

It seems like he is saying the following:

If you build a reciever with high sensitivity, you will not need much antenna gain, so the antenna can be small.

If you build a receiver with higher selectivity, you will be able to use components that generate more spurs, since the selectivity will filter the unwanted spurious signals out.

lower Power Diss = Lower battery lifetime, obviously.

AGC 20 dB, who knows?

If you build a receiver that has high IIP3 (does not readily generate out of band spurious, like 2-tne third order products) you do not need an antenna with high directivity, so the antenna can be small. An omnidirectional antenna is small, but will let in interfering signals from all directions, so the receiver must be able to handle those interfering signals without spectrally regrowing into the recievers IF frequency band.