Compact Ground-Covered Differential Transmission Line with Multiple Core Layers in 65 nm CMOS

This paper presents a modified differential transmission line with multiple core layers applied for base-band phased arrays in 65 nm CMOS technology. By adopting more than one metal layers as signal carrier, the proposed line achieves lower transmission loss compared with differential transmission line using single metal layer as core layer. For line with length of 1000 μm at frequency of 1 GHz, when metal layer 6 is added to metal layer 7 to compose the signal carrier, the magnitude performance is increased from -2.37 dB to -1.45 dB. In addition, the magnitude of S parameter reaches -1.15 dB for transmission line utilizing three layers as core layers from metal layer 7 to layer 5, while the phase is maintained as a moderate value of -17.27°. The width of modified line is 10 μm and height is <2.92 μm, including covered ground layer.