2011 Volume 8 Issue 9 Pages 629-635
In this paper, it is demonstrated that the first and second spurious passbands suppression in microstrip hairpin filters can be achieved by simply patterning appropriate geometries of several Defected Microstrip Structure (DMS) in parallel coupled sections. By properly tuning DMS resonator dimensions, multiple transmission zeros can be generated in the vicinity of spurious harmonics and a wide stopband can be obtained. Experimental results verify that 25dB and 40dB suppression for the first and the second harmonics, respectively, without affecting the main passband response.