An Integrated Tunable Electrical-Balance Filter with >60dB Stopband Attenuation and 1.75-3.7GHz Stopband Tuning Range

This paper proposes the concept of electrical balance filters to enable integrated, tunable RF filters, where a pass- and stopband are designed by the change in electrical-balance across frequency. These filters can be constructed using low Q integrated LC resonators. The stopband frequency is the frequency where two on chip balance networks are tuned to be equal in impedance or ‘balanced’, while the passband frequency is the frequency where the balance condition is disturbed as much as possible for low insertion loss. A 1.5mm2 electrical balance low-pass filter prototype is implemented in 0.18µm SOI CMOS. It has <4dB insertion loss at 1GHz with a >60dB, >33MHz stopband tunable from 1.75 to 3.7 GHz.

Publication year:2016

Keywords:Electrical-balance, RF, filter, tunable filter, impedance-based filtering, low-loss, high attenuation

Accessibility:Open