A millimeter-wave ultra-wideband four-way switch filter module based on novel three-line microstrip structure band-pass filters

Abstract

This paper presents a millimeter-wave ultra-wideband four-way switch filter module integrating six building blocks including four band-pass filters and two switches. The switch filter module works at whole Ka-band (26-40GHz) and consists of four wideband band-pass filters and two monolithic microwave integrated circuit (MMIC) single pole four throw (SP4T) switches. The four wideband band-pass filters are realized by a novel three-line microstrip structure band-pass filter. Compared with the traditional three-line filter, the proposed three-line filter not only retains virtues of traditional three-line filter, but also resolves drawbacks of it, which include discontinuities between adjacent sections, many parameters of design, and no effective matching circuits at input/output ports. The proposed three-line filter is validated by electromagnetic simulation. The developed switch filter module is fabricated using hybrid integrated technology, which has a size of 64mm×44mm×7.5mm. The fabricated switch filter module exhibits good performances: for four different states, the measured insertion loss and return loss are all better than 8.5dB and 10dB in each pass-band, respectively.