Broad Stopband, Wide Passband, Bandstop Filter using the Spurious Bypass Method

In [1], a method was presented for bypassing spurious passband responses due either to unwanted periodic resonances or of resonances due to parasitics, in a very wideband highpass filter. In that same reference, mention was made for potential application to a bandstop filter, where the bandstop portion is very wide, and the passband is also very wide. In [7] and [8], a lumped-distributed circuit was presented, with a stopband covering 962 MHz to 1210 MHz, with a passband extending to about 6 GHz. In this paper, we have taken the proposed bandstop briefly discussed of [1] and will show that using the proposed bypass method, the same stopband can be achieved, but with a passband extending to 18 GHz. As well, the size of the proposed filter is less than 25% of that of the filter in [7].