A wideband and self-packaged D-CRLH diplexer based on substrate-integrated suspended line

Abstract

This letter presents a new microstrip diplexer with self-packaged and wide bandwidth based on substrate-integrated suspended line (SISL) technology. Diplexer consists of D-CRLH filters which include mixed coupling. The electromagnetic interaction is canceled out in the filter, generating two transmission zeros and giving the filter good stopband suppression. Diplexer utilizes a T-junction to make filters work in parallel. Each channel filter can be individually controlled. To validate the proposal, a diplexer operating at 1.88GHz and 2.64GHz with fractional bandwidth (FBW) of 14.6% and 19.1% is designed and fabricated. A good agreement is perceived between measured and simulated.