Abstract: A LTCC (low-temperature co-fired ceramic) narrow bandpass filter of Ka-band is presented. The filter has a 2.24% fractional bandwidth with the center frequency at 35.78GHz, and its Insertion Loss is better than 0.1dB(any metal or substrate loss is ignored).With increasing the cross-coupling among stubs, the input and output ports, the filter has three transmission zeros. Using the EM simulation, the excellent depression is higher than 20dB above 36.9GHz, and higher than 30dB below 34.9GHz. This filter is used in the millimeter-wave T/R module for rejecting the mirror frequency and spurious responses.