In this paper, two miniaturized SIW filters in the Ku-band are investigated, and the equivalent magnetic wall cutting method is adopted to obtain the quarter mode substrate integrated waveguide in order to meet the required miniaturization specifications. Two distinct QMSIW configurations, designated as triangular QMSIW and rectangular QMSIW, are developed based on the distinct equivalent magnetic wall cuts. Subsequently, the QMSIW filters with two distinct structural configurations are subjected to investigation. However, the out-of-band rejection capability of the designed QMSIW filters is not high, and therefore the complementary split ring resonators are loaded in the QMSIW resonant cavity in order to improve the out-of-band rejection. Then we employ the electromagnetic simulation software to simulate the proposed QMSIW filters with the two different structural configurations, and obtain the ensuing results. The passband range of the rectangular QMSIW filter loading the CSRRs is from 14.94 to 16.02 GHz, with a relative bandwidth of 6.97%. The insertion loss is better than 0.6 dB, the return loss is better than 15 dB, and the out-of-band rejection is better than 35 dB@19~20 GHz, with a size of 0.2×0.314λ2g. The triangular QMSIW structure filter loading the CSRRs exhibits a passband range of 14.89~16.11 GHz, with a relative bandwidth of 7.87%. The insertion loss is better than 0.6 dB, the return loss is better than 17.2 dB, and the out-of-band rejection is better than 40 dB@19~20 GHz with a size of 0.27×0.27λ2g. Both modified QMSIW filters are processed using an alumina oxide thin film and tested with GSG probes and subsequent to the actual test, it is determined that the test results are essentially consistent with the simulation results and met the expectations.