Multilayer design techniques for extremely miniaturized CMOS microwave and millimeter-wave distributed passive circuits

Multilayer design techniques are investigated for reducing the size and enhancing the performance of microwave and millimeter-wave distributed circuits in CMOS. Various distributed passive circuits are implemented in a standard 0.25-mu m RF/mixed-signal process, including a novel broadside-coupled Lange coupler, a microstrip ring hybrid, and a hairpin resonator incorporating a complementary slow-wave structure. The broadside-coupled Lange coupler exhibits -3.3 to -3.35 dB through, -3.3 to -3.7 dB coupling, more than 12-dB isolation, and 15-dB return loss across 25-35 GHz while occupying only 217 x 185 mu m of chip area. The multilayer ring hybrid has -3.1 to -3.18 dB through, -5.1 to -5.7 dB coupling, and more than 17-dB isolation and 10-dB return loss from 25-35 GHz while occupying 282 x 314 mu m. A slow-wave structure based on multilayer complementary design principle is implemented for hairpin resonators. The measured quality factor of the multilayer complementary slow-wave hairpin resonator increases to about 14.5 from 11.3 for a similar sized resonator with a single-layer slow-wave structure, while retaining similar size-reduction properties as the latter.