A novel general structure of tunable frequency selective surface without bias grid

A novel, general structure of tunable frequency-selective surface that does not require additional bias networks is presented. Varactor diodes are positioned in the middle of each cell, and no via is required. Inductors between the cells provide DC connections, which also choke high frequency signal. Two FSS patterns are applied in the tunable structure. Simulation results of the two FSS patterns both show that by altering the capacitance of the varactors from 0.3 to 3.0 pF, a wide frequency tunability can be achieved, and at the same time the bandwidth becomes obviously wider.