On the design of LTCC filter for millimeter-waves

To test the repeatability of scattering parameters of LTCC bandpass filters at millimeter-waves a dual-mode stripline patch filter was designed. Measurement results showed 2.8 dB insertion loss and 12 dB return loss in passband. The measurements of two test structures exhibited good coincidence of scattering parameters, which are in a good agreement with the predicted results. To prevent the influence of the stripline package onto the filter performance additional investigations were carried out. As a result the suitable configuration of feed lines were chosen.