As the transmission properties of Frequency Selective Surfaces(FSS) will get worse because of the air gaps between FSS and original radome in the experimental stages, a novel snow loop element FSS was designed to reduce the effect of air gaps. The theoretical simulation was performed by using the mode matching method. For contrast, the best FSS structure designs of the novel snow loop element and Y loop element for the assumed qualification were chosen out respectively. The equivalent FSS sample plates were fabricated by using photolithographiy, and the transmission properties were tested in a microwave dark room to check the simulation results. Both the calculating and the testing results show that the novel element FSS meets the transmission request in a quite wide air gap range (190-6 500 μm), which is much better than the best Y loop design(320-1 900 μm). Advantages of this new type snow loop element FSS were briefly analyzed. It demonstrates that the snow loop FSS has very low sensitivity to the air gaps, which provides a new method for the FSS study in the experimental stages.