Design and Applications of a 300–800 MHz Tunable Matching Network

In this paper, the optimized design, characterization and applications of a broadband 300-800 MHz (~ 91% fractional bandwidth) digitally-controlled tunable matching network is presented. The design employs PIN diodes as switching components and a repetitive structure of basic cells using lumped reactive elements. After an intensive and complex optimization process, a Smith chart coverage (return losses better than 10 dB and losses lower than 2 dB) above 60% is obtained in all the bandwidth reaching 75% in the middle of the band (400-700 MHz). The potential of the manufactured tunable matching network for antenna mismatch compensation, antenna bandwidth extension and power amplifier efficiency improvement in back-off is showed.