Micromachined thick-metal coplanar coupled-line filters and couplers

Highly-coupled couplers (3-dB and 6-dB) are necessary for a wide range of millimeter-wave coplanar circuits. The high line-to-line capacitance required for these couplers is impossible to achieve with thin-film planar coupled lines. Using 80 /spl mu/m-thick conductors patterned using a 3-D X-ray micromachining technique, we have successfully demonstrated a 15 GHz 6-dB coupler and a single-section coupled-line BPF that utilizes a 3-dB coupler geometry.