Aiming at the problem of water-intrusion into closures in fiber optic cable operation and maintenance,and based on the description of the causes and harm of water-intrusion,a water-intrusion detecting sensor for fiber optic cable closure,which makes use of water-blocking tape,is designed and fabricated.

This article describes the classification and features of water-blocking tapes for fiber optic cable, and provides the choice basis according to their property anlysis.

Symmetry spiral microstrip resonators for wide-stopband filters;

When a vector network analyzer measured a low pass filter,the measurement result of the frequency response showed that there was an extreme measurement error in the filter s stopband.

Without increasing the size of the microstrip, the bandwidth of stopband or passband of the novel PBG microstrip line can be changed when the dispersion between the central frequency of PBG st.

The design formulae of the stopband equiripple Chebyshev filters are described briefly.

The filter has not only wider stop band but also decreased dimension (approximately 40% shorter) comparing with traditional direct-coupled half wave resonator ones.

The effects of DGS dimensions on stop band characteristics were presented.

Objective To design a bandstop digital filter for cancelling the 50HZ noise.

Bandstop filter is mid-width;The passband to rejection band transition slope is steep;The characteristic of Low cost and be prone to manufacture is acquired.