UNILATERALLY INJECTION-LOCKED GUNN OSCILLATOR PAIR ACTING AS A MICROWAVE ACTIVE NOTCH FILTER

In this paper, we present the theory and design of a novel microwave active notch filter operating at X-band (8 GHz-12.4 GHz). The notch filter has a notch frequency of 10.22 GHz and a 3 dB calculated bandwidth of 87 MHz, the corresponding 3 dB experimental bandwidth is 120 MHz. The filter is designed using a magic tee and two tunable X-band Gunn oscillators injection-locked to the input interference to be eliminated. The special features of this filter are that it is of low noise, tunable and signal tracking character and possesses considerable power handling capacity.