Closed-Form Design of Gysel Power Divider With Only One Isolation Resistor

An innovative design of low profile in-phase Gysel power divider (PD) by introducing efficient modifications is presented. The conventional Gysel uses a half-wave line and two isolation resistors as a Π network. The proposed modification converts it to a T network with only one isolation resistor and two quarter-wave lines that can reduce the design complexity, occupied area and fabrication cost. To obtain the accurate values of the line impedance and isolation resistance, closed-form equations based on a new viewpoint are derived. Two prototypes with narrow and broadband characteristics are realized at 3 GHz. The PDs have good magnitude and phase balances and better harmonic performance, compared to the conventional one.