Design considerations for realization of Ku - band hairpin micro-strip band pass filter with high rejections at stop band

This paper presents design, simulation, optimization and measured results of seven section miniaturized hairpin band pass filter designed in Ku-band. Considering critical parameters for the design of filter such as narrow bandwidth, selectivity, high rejection, form factor, ease of manufacture, ease of assembly etc, hairpin topology realized as a printed micro-strip is found to be a better option. Hence a micro-strip based miniaturized hairpin (tapped) BPF has been designed and discussed. Practical design considerations to achieve optimum results considering BW reduction, out of band rejections, channelization of filter etc have also been discussed in this paper. Design, simulation and optimization has been done in ADS and CST EM Software. The filter designed for l.1GHz BW (1dB BW) with a center frequency 13.1GHz, is realized having in-band insertion loss of 3.8dB max, with peak VSWR of 1.8:1, and rejection greater than 60dB at 15% away on either sides of the band edge. This filter is realized in a micro-strip configuration (Dimension-20 x 6 mm2) on a 10 mil thick Rogers’s RT 5880 substrate for its ease of manufacturing, ease of assembly & flexibility in tuning. The simulation data and tested data are having a good correlation.