Abstract: Cross coupled resonator filters with the sharp cutoffs at the edge of the pass band are discussed in this paper.Taking cascaded-quadruplet(CQ) and cascadedtriplet(CT) coupling topology as the circuit unit,we find the position of each transmission zero or pair of zeros in stop band is independently modified when the units are cascaded,It makes the filter easy to tune and the example to show this result is given.Finally by using full-wave EM software,a hairpin microstrip filter is designed,simulated and optimized.