Improved Design of Ku-Band Interdigital Cavity Filter

In this paper, a method for realizing Ku-band bandpass filter design by using improved interdigital cavity structure is proposed. The cavity filter was designed at the frequency range of 10.7GHz~12.75GHz. Its lower stopband (9.85 GHz~10.35 GHz) attenuation reach -40dB and its upper stopband (13.75 GHz~14.5 GHz) attenuation can reach - 50 dB. High stopband suppression requirement can be obtained through introducing the transmission zero. Moreover, we use the tuning screws to achieve the miniaturization of the filter. The actual test results show that filter performance is obtained with insertion loss (S21) of 1dB and the return loss (S11) of -17dB. Both the input and output Voltage Standing Wave Ratio (VSWR) are less than 1.35 within the bandwidth.