Abstract

A defected microstrip band reject filter by multiple tunable structures to sieve out the unwanted signal interferences in opposition to UWB systems especially narrowband is put forward and analyzed. A 50- Ohm microstrip band line is employed to obtain the anticipated defected microstrip band reject function. An oxbow notch (OBN), an inverted C-notch (ICN) and a horizontal cross notch (HCN) are incised on the substrate. Tuned measurements of the OBN, ICN, and HCN are selected to provide good tunable characteristics. The microstrip band reject filter is evaluated by the analogous circuit model and its simulations are presented for further analysis. The controllable center frequencies and miniature size are a few advantages of the reject filter obtained from the simulation and analysis results.

Keywords: Tunable reject filter; Defected microstrip-band structure; Oxbow notch; Horizontal cross notch; Impedance Characteristics; In-verted C-notch