Miniaturised equal/unequal SIW power divider with bandpass response loaded by CSRRs

A miniaturised equal/unequal substrate integrated waveguide power divider with bandpass filtering response loaded by complementary split-ring resonators (CSRRs) is proposed. The proposed structure is based on the theory of evanescent mode propagation. The use of the CSRRs enables the filtering function of the power divider and is able to reduce its size. By changing the orientations of the CSRRs, the equal/unequal power dividers are achieved. In the unequal power divider, the power ratio can be arbitrarily controlled by carefully tuning the parameters of the CSRRs and locations of the output ports. Three miniaturised filtering power divider samples with power division ratios of 1:1, 1:4 and 1:8 are fabricated and tested. These designs resonate at the frequency of 5.8 GHz covering WLAN. The sizes of the proposed power dividers (1:1, 1:4 and 1:8) are only 0.37 x 0.21(g)(2), 0.3 x 0.16(g)(2) and 0.3 x 0.15(g)(2), respectively.