analysis and design tunable dual-band bandpass filter of a second-order maximally flat using miniaturized technique

this study presented an analysis and design of tunable dual-band bandpass filter using miniaturized technique. the miniaturized technique makes the weight and volume of the filter smaller. this design is based on a combination of parallel coupled lines of microstrip. a second-order low pass filter was designed by using mathematical equations. the low pass filter was transferred into a middle pass filter using these equations. then by using tuning technique this filter was turned into a tunable dual-band bandpass filter. the used sublayer of rt-durroid-5880 with ε_r=2.21 and loss tangent was 0.0009. the ads software was used to do all the diagrams and simulations which lead to designing a double band filter with 1ghz bandwidth.