  This paper presents a micromachined bandpass filter with miniature size that
has relatively outstanding performance. A silicon-based eight-order microstrip
bandpass filter is fabricated and measured. A novel design method of the
interdigital filter that can create two transmission zeros is described. The
location of the transmission zeros can be shifted arbitrarily in the stopband.
By adjusting the zero location properly, the filter provides much better skirt
rejection and lower insertion loss than a conventional microstrip interdigital
filter. To reduce the chip size, through-silicon-substrate-via-hole is used.
Good experimental results are obtained.
