A novel double T-shaped microstrip bandstop filter with DGS and a novel double H-shaped microstrip bandpass filter with DGS are proposed,and their performances are simulated.

A new design of notch filter in servo systems;

This paper analyzes the vibration source of unmanned helicopter and designs a sort of vibration damper with plastic material through building a damping model and designs an analog notch filter to eliminate the side-effect of resonance due to the system s inherent frequency.

Meanwhile, the switched capacitor notch filter is designed, which can adjust center frequency freely by changing the switching clock frequency and make the center frequency highly accurate and stable.

The Design of Bandstop Filter with ispPAC;

C-ring DGS bandstop filter

Moreover,a compact microwave combiner is designed with the EBG structure,which contains two bandstop filters and one "T" junction.

Simulation results show that the CPW band-stop filter has wide and deep stopband,it can operate in different bands by changes in the size of the DGS cell,and its performance can be improved .

It is proved that a new active filter can realize four kind of second order filter function by using a CCⅡ and seven passive element changing character of passive element in circuit(resistance, capacitance):high-pass,low-pass, band-pass,band-stop filter.