Inherent Impedance Transformation and Isolation in Dual-Band Balun For RF Front End Applications

This paper presents a balun architecture with the inherent impedance transformation between the balanced and unbalanced ports. Also, the balun provides the isolation between the balanced ports while working at the two arbitrary frequencies concurrently. The systematic design analysis of the proposed balun architecture is also provided in the paper with the analytical design equations in closed-form. The working of the proposed balun architecture is also demonstrated through the electromagnetic simulation on an industry standard simulation tool working at a frequency ratio (r =2) and impedance ratio (k=2). The simulation results of the optimized electromagnetic architecture are in good agreements with the calculated results.