Synthesis, design and implementation of ultra-wideband impulse radio active MMIC matched filters

Abstract

In this paper, we present a comprehensive framework from synthesis to implementation of active matched filters for UWB Impulse Radio. The method delays and sums UWB pulses coherently to strengthen the signal over white Gaussian noise. Theoretical analysis shows that the signal peak is maximized against noise, and an arbitrary transfer function could be realized by adjusting filter parameters. To verify the concept, a four-stage matched filter operating in 3-5 GHz with 360 degrees phase delay is demonstrated first. It is implemented in a commercial 2-μm GaAs HBT process and achieves a power gain of 13.8 dB with a 10 dB bandwidth of 1.3 GHz. Based on a similar architecture, another design is presented but with only half of the delay. It has a power gain of 15.9 dB at the center frequency of 4 GHz and a 10 dB bandwidth of 2.3 GHz. An advantage of the proposed method is a precise control of the impulse response that can be matched to either symmetrical or asymmetrical UWB pulses by taking a time domain design approach.