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Two integrated bandpass filters have been designed and fabricated on standard 130 nm CMOS technology. The lumped element, third-order Butterworth bandpass filters at 9.45 and 1.75 GHz are designed for sub-band filtering in a spectrum monitoring receiver function in a future cognitive radio. A series coupled resonator topology is selected and a novel delta-star transformation technique is applied to obtain element values suitable for reliable fabrication on an integrated circuit. Occupying die areas of 780 × 200 μm and 1750 × 500 μm each, the filters achieve insertion losses of 15.6 and 8.6 dB, and band-widths of 1 GHz and 210 MHz, respectively, which are suitable for the chosen spectrum monitor receiver architecture.