X‐band substrate integrated waveguide bandpass filter using novel defected ground structure cell

Abstract

ABSTRACTIn this letter, an X‐band wide stopband bandpass filter is presented, which combines substrate integrated waveguide with defected ground structure (DGS) cells. Three DGS cells, including a pair of face to face modified dumbbells embedded with E‐shape slots, are adopted to achieve bandpass performance. The wide stopband is implemented by loading low pass filter, which is designed using stepped impedance open stubs, at the input/output ports. To validate the methodology, a filter with center frequency of 8.55 GHz is designed and measured, and the measured results are in good agreement with simulated ones. The designed filter has an insertion loss of 1.45 dB, a return loss of 18.8 dB in passband, and a wide upper stopband of more than 30‐dB suppression up to 45 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1156–1160, 2015