High performance bandstop filter design and investigation using physical model for WiMAX measurement equipment

A novel compact planar bandstop filter with deep stopband rejection and ultra-wide passband bandwidth is introduced for worldwide interoperability microwave access (WiMAX) test equipment. The physical based equivalent circuited model is introduced and investigated. A 2.5GHz bandstop filter is designed and used for worldwide interoperability microwave access (WiMAX) test equipment. The designed fifth-order bandstop filter covers rejection band of 2.3GHz∼2.85GHz with rejection more than 60dB and insertion loss less than 2dB. The center frequency of the second stopband appears as high as 5.8 times (15GHz) of that of the fundamental stopband.