In-line Vector Modulator Integration in Dielectric-filled Waveguide

This article proposes a scalable substrate-integrated waveguide (SIW) module accommodating an in-line vector modulator monolithic millimeter integrated circuit (MMIC). The SIW module is realized with low-temperature co-fired ceramic (LTCC) technology, and it can be inserted in a dielectric-filled waveguide (DFWG). The module combines $\lambda {g}/4$ -transformer-based $E$ plane tapering and SIWs on LTCC with the wire-bonded vector modulator. The proposed active LTCC module and two passive test structures (i.e., a constant-height-SIW module and a SIW module with $E$ plane taperings) are manufactured and tested as in-line modules in a DFWG. The passive test structures with the waveguide-to-DFWG and DFWG-to-SIW transitions measure 3.1 and 4.6 dB of insertion loss on average, respectively, at the 71-81 GHz frequency range. The active LTCC module measurements demonstrate a DFWG with phase and amplitude tuning capability and gain up to 17.6 dB within the same frequency range. A four-channel mock-up module with $\lambda {0}/2$ channel spacing is designed and manufactured to demonstrate the scalability of the design.