The pilot stated that he was just turning from the downwind to the base leg of the airport’s traffic pattern when the experimental airplane’s engine had a total loss of power. He trimmed the airplane for best glide speed and maneuvered the airplane toward the runway. The airport has a tall perimeter fence, which ran across the approach end of the intended runway. The airplane did not have sufficient altitude to clear the fence and impacted into it resulting in the right wing incurring structural damage before coming to a complete stop. The pilot exited the airplane uninjured. A post wreckage examination revealed that the engine air inlet cowling ducting separated from its attaching material, which caused the ducting tube to slide into the engine air flow control box; blocking the carburetor’s air inlet.