Ask about the energy propgation in a circuit

[waitingforme]

I have a puzzle about the energy propagation in a circuit. the circuit is illustrated as following. there are two ways the energy goes along. But at the junction, the phase difference of the electric field is pi, so the output energy should be zero. But where dose the energy go?
Also, how to explain the array antennas' null point in its pattern? how to describe the behavior of the energy?
thanks!

 

[terry andy]

the two way energy interface and the source energy is not cosumed!!

 

[waitingforme]

~~~~does the energy go back to the source and disabled the sourse?