Self Adaptive Microwave Filters

This paper describes a self adaptive bandpass filter that performs lowpass filtering on the instantaneous frequency of a signal, corresponding to a bandpass filter centred at the unknown carrier frequency of the signal. These devices use non-linear components, which perform linear operations on the instantaneous frequency of a signal. In this paper, new design techniques for these filters, incorporating frequency divide by N/multiply by N/2 blocks are presented, enabling significant reduction in system complexity. An experimental prototype working at 10GHz showed an increase in the received signal power by ap 15dB while maintaining the noise floor level without prior knowledge of the signal frequency or the channel characteristics