module antenna component

Anyone know what is this component? in the Cypress DSSS module.

Edit: sorry, wrong photo

My guess would be, based on location right before the antenna, it is either a balun to do impedance matching between the board and antenna, or a rf switch.

A balun will have (almost) zero resistance between the in and out pins.

If you could trace the connections to it, it might allow a better guess.

(Google for "2.4GHz balun" to see if it is similar)

Yes, I think so. I did not see this in the reference design inside the datasheet of T212.

Should the impedance be 50ohm with resistance 0hm? or other value to match specific antenna?

To my knowledge, Walkera have been using that same component in all their 2.4GHz radios.
Datasheet for that component is here....
info.tactnet.co.jp/soshin/j/product/pdf/MDR747F.pdf

kenkenlau wrote: Should the impedance be 50ohm with resistance 0hm? or other value to match specific antenna?

The through-resistance of a balun measured with a multimeter using DC current is practically Zero ohm. At 2.4GHz it does both balance-to-unbalance and impedance conversion, typical 200ohm balanced (board side) to 50ohm unbalanced (antenna side) normally onto a 50ohm coaxial cable like RG174. (In such a case it would be a 4:1 Balun).

EDIT: To me it looked like a rectangular 6 pin device, after a second look it is more likely the filter as stated above.