2.4-GHz $Q$ -Enhanced Lumped Ring Filter With Two Transmission Zeros Using 0.18- $\mu$ m SiGe BiCMOS Process

A 2.4-GHz Q-enhanced lumped ring filter with a narrow bandpass response and two stopband-rejection transmission zeros using 0.18-μm SiGe BiCMOS technology is demonstrated in this letter. A transformer-based Q-enhanced technique is employed to boost the Q-factor of on-chip inductors for low passband insertion loss. The measured results show zero dB insertion loss, 120-MHz 3-dB bandwidth for the passband centered at 2.45 GHz and with two transmission zeros at 2.35 and 2.65 GHz, respectively. The noise figure is about 14.5 dB, IP1dB is about -15.2 dBm and IIP3 is about -4.5 dBm, respectively. The total current consumption is 9.9 mA at 1.8 V supply voltage.