摘要
A voltage-controlled oscillator (VCO) with the twisted inductor is tested by using the chip-level near-field coupling measurement for evaluating the radiated electromagnetic (EM) emission. The testing setup resembles the modern stacked packaging scheme by utilizing the flip-chip bonding and integrated passive device (IPD) technology. An embedded coplanar waveguide (CPW) line on IPD carrier is utilized to capture the EM emission via near-field coupling. Two 0.18- μm CMOS 6-GHz VCOs, one with a conventional spiral inductor and the other with a twisted inductor, are tested. The VCO utilizing the twisted inductor exhibited a notable improvement of over 6 dB in EM emission compared to the one employing a conventional inductor.