A Novel Concept of Virtual Impedance for High Frequency Tri-Band Impedance Matching Networks

This brief introduces a novel concept of a virtual impedance for tri-band impedance matching. The proposed mathematical concept, when applied in practical realization, simplifies the design of tri-band matching to a great extent and also enhances the achievable frequency transformation ratios beyond 7.3. A good agreement between simulation and measurement results on a prototype, designed on RO5880 substrate, operating at three unrelated commercial frequencies of 1.8 GHz, 2.4 GHz, and 5.8 GHz demonstrate the effectiveness of the presented concept.