A 1.2 GHz semi-digital reconfigurable FIR bandpass filter with passive power combiner

Abstract

This paper presents a reconfigurable semi-digital RFFIR filter suitable for digital transmitters using 1-bit DeltaSigma signal generation. A transmission line based 5-channel power combiner allows both increase of output power and programmable filtering of the signal. A prototype has been built with 65 nm CMOS and Integrated Passive Devices (IPD) technologies. The system exhibits a 14 dB power gain for a peak power of 17 dBm at 1.2 GHz and an attenuation of out-of band noise of up to 15 dB. CMOS and IPD chip size are respectively 2.05 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 17.78 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .