HMSIW Cavity Filters Employing Various Complementary Split-Ring Resonators for Microwave Remote Sensing Applications

In this work, bandpass filters employing half-mode substrate integrated waveguide (HMSIW) cavities and various modified complementary split-ring resonators (CSRRs) are presented. The two modified CSRRs, which are called as Type-I and Type-II CSRRs, can exhibit larger effective inductance and capacitance, and eventually to contribute to the size miniaturization of the resonators. Thereafter, as the two CSRRs are independently loaded into HMSIW cavities, the newly- formed HMSIW-CSRR cavity resonators can achieve more size reduction as compared with the HMSIW cavity with the conventional CSRR. To demonstrate the proposed concept, two HMSIW cavity bandpass filters independently loaded with the proposed Type-I and Type-II CSRRs are implemented. Experimental results shows that measurements of the proposed filters agree with their corresponding simulations well. Meanwhile, as compared with some similar works, the two proposed filters achieve size reduction of 76.8% and 78.6%, respectively, as well as good selectivity, illustrating their suitability for the system integration application in microwave remote sensing and radar systems.