Miniature suspended-substrate stripline filter

A new suspended-substrate stripline structure admitting implementation of miniature highly selective narrowband filters is studied. The diminutiveness of the structure is achieved due to introducing supplementary strip conductors, which considerably reduce the coupling between the resonators. Furthermore, in this case attenuation poles arise on both sides of the passband appreciably improving the device selectivity. Experimental results of the manufactured four-resonator filter are presented.