Compact long differential transmission line with ground cavity in 65 nm CMOS

This paper presents a base-band differential transmission line for a phased-array receiver in 65 nm CMOS. It mainly consists of two parallel metal lines as signal carriers with surrounding layers to form a close cavity. The 1000-μm long differential transmission line with a line width of 1 μm achieves a transmittance from -2.99 dB to -2.15 dB and a relative phase from -28.54° to 0 over 0-2 GHz. Based on the passive structure, the power consumption is zero, and the core cross-section occupies a compact area of 10 μm *2.11 μm.