New MMIC approach for low noise high order active filters

This paper presents a new design approach for achieving microwave active filters, based on actively coupled resonators. The method, dedicated to narrowband and wideband filtering applications, associates core cells with different resonance frequencies, adjusted separately, to synthesize Butterworth, Chebyshev or other all-pole approximation. It is illustrated by two chips: - a 3-pole band pass filter centered at 12GHz characterized by 15.5 dB gain, a 3dB bandwidth of 1.8 GHz and rejection better than 15 dB at 1.1 GHz to the 3dB band limits - a 5-pole bandpass filter centered at 14GHz, a 3dB bandwidth of 1.6 GHz, a gain as high as 30 dB, and a low noise figure (less than 3 dB in the whole band). Its rejection is better than 37 dB at 1.1 GHz off the 3dB band.