Need help for 315MhZ design

Dear all,

I'm designing a wireless system using 315Mhz frequency.

The antenna of the system need to be inside the casing. The system is power by 2 x AAA battery (3.3v).

I use 12v step up regulator to increase the 315mHz module strength. If using 3.3v, the signal strength is between -48dbm to -45dbm.
If using 12v, the signal strength is up to -40dbm to -38dbm.

My problem is i need to achieve at lease -25dbm, because I need to achieve 3 floor distance.

Please give advice. Thanks.

Power supply voltage has not much impact on RF Power Output.If you need more power check your design again.
The antenna that is in-case may be a trouble at that frequency.
How did you measure RF Power Output ? At the antenna or before ?
There are many parameters that impact RF Power, it's hard to say something concrete without seeing your design..

Sorry for the late reply.

I using spectrum analyzer to analysis the signal strength.
Do you have any reference design? Still having problem on the signal strength.

http://www.maximintegrated.com/datas...ex.mvp/id/4754

Use IC circuits for that application to minimize headache.

Thanks for the recommendation. Will test and see.
Get back to you as soon as finish test.