VERY WIDE BANDWIDTH COMPOSITE BANDPASS FILTER WITH STEEP ROLL-OFF

摘要

A very wide bandwidth composite band pass filter with steep roll-off of a corresponding passband includes a band pass filter and a high-Q acoustic resonator. The band pass filter has a corresponding passband with a very wide bandwidth and a passband roll-off. The high-Q acoustic filter has a corresponding stopband with a roll-off steeper than the passband roll-off, the high-Q acoustic filter being connected in parallel with the band pass filter such that a portion of the stopband is within the passband of the band pass filter, forming a combined passband. A frequency range of the combined passband is approximately the same as a frequency range of the passband of the band pass filter, and a combined roll-off of the combined passband is steeper on one side than the passband roll-off of the band pass filter.