Simulation design of a compact filter based on multilayer left-handed transmission line

Based on the multilayered composite-right/left-handed transmission line structure proposed by Yasushi Horii and reference [1], some improvements are presented in this paper. The improved structure is of higher center frequency, much less undesired resonances, and greater work passband. Moreover, a compact filter in X-band is proposed based on some conclusions of simulations. With particularly small dimension of 5.1 mm×3.8 mm at 9.5 GHz, the proposed filter demonstrates a good performance, such as 1 G bandwidth, less than 0.7 dB in-band loss, and the transmission coefficients (S₂₁) at 8 GHz low to -30 dB.