A Novel Concurrent Dual Band Matching Network for Complex to Real Impedance Matching for RF Applications

A novel and simple technique to match Frequency Dependent Complex Loads (FDCLs) to real source impedance at any two arbitrary frequencies is presented. The proposed structure consists of stubs and two 50 Ohms series transmission lines, making it easy to fabricate. This arrangement allows concurrent operability. It has the versatility to transform all types of complex loads at any frequency ratio, which may not be possible with other conventional techniques. In this brief, the limitations of single section transmission line to transform FDCLs to two complex conjugate loads (CCLs) at two frequencies is thoroughly studied. In the proposed scheme, an L-section is used to match the complex load to source impedance at one frequency; and another section consisting of a transmission line and a combination of open-short stub is used to match the load at other frequency. Three prototype matching networks for frequency ratios 6.5, 2.3 and 1.583 are designed and implemented on ROGERS RO4003 substrate having dielectric constant of 3.38 and substrate height of 20 mils. The simulated and the measured results are in a good accordance.