Photoimageable Thick-Film Micro-Coaxial Line for DC-to-Millimeter-Wave Broadband Applications

In this paper, the development of an innovative micro-coaxial line technology is presented and developed for dc-to-millimeter-wave broadband applications. This nondispersive line is fabricated using a simple photoimageable thick-film process. Wave-guiding properties of the developed micro-coaxial line are extracted from 1 to 110 GHz, showing an extremely broadband operation. A single transition from micro-coaxial line to grounded coplanar waveguide is used to cover the entire frequency range available through single vector network analyzer. Passive devices are then demonstrated in the form of a 60 GHz band-pass filter and an 8 dB coupler using vertically coupled lines. Measured results of the demonstrative filter show an excellent agreement with simulated results, which present very good performances with 1.5 dB insertion loss over the frequency band of interest. The broadband coupler exhibits an exceptional multioctave bandwidth (from 20 to 82 GHz) and low loss at 1.5 dB.