I've just tested only the oscilloscope, it has the same problem
Not have RF wave propagation
Have RF wave transmission
This is my PCB
I connected a sensor to testing, so I made 4 wires to extend board, SCL, SDA, VCC and GND as shown in the above picture.
@andre_teprom
Pullup resistors with high values ? ==> I used 10K resistor to pull up
I2C routed in a spread path ?==> My English is not good, could you explain me more detail about that.
PCB not sufficiently grounded ? ==> I check with Muliplier, it is connected well.
I don't see any capacitors. And you do not understand what grounding I'm talking about. It is impossible to check with multimeter. Forget, dude, this will never work.
At the above picture it is not clear what is connected to what. Anyay, I2C is not suited to interconnect boards appart like that. You should reduce the length of the wires, as well as to twist them along with a gnd wire, just to act as a 'shield' for induced EMI noise. As a further attempt, you could try reducing the pullup resistors and reduce the I2C clock rate, which wasn't also mentioned so far.
@Easyrider83: Could you please explain me more about what grounding that you mentioned. I have only one 4.7uF capacitor from vcc to ground, it is designed based on the datasheet.
Before start making your own design, review at least few of them done by proffessionals. Open you PC at look at the PCB. You will see solid poligons for grounding and a lot of capacitors around all chips to reduce noise over supply voltage.