Patent ID: 8633785

Claim:
A Marchand balun circuit comprising: a Marchand balun comprising an unbalanced terminal and two balanced terminals; and a matching circuit comprising: an unbalanced matching circuit comprising a first resistor, a first impedance, and a second impedance, wherein, the first impedance and the second impedance are connected between the unbalanced terminal and ground in series, the first resistor is connected between the ground and a first connection node of the first impedance and the second impedance, wherein the first connection node is configured to connect to an unbalanced device; and a balanced matching circuit comprising a second resistor, a third resistor, a third impedance, a fourth impedance, a fifth impedance, and a sixth impedance, wherein, the third impedance and the fourth impedance are connected between one balanced terminal and the ground in series, the fifth impedance and the sixth impedance are connected between the other balanced terminal and the ground in series, the second resistor is connected between the ground and a second connection node of the third impedance and the fourth impedance, the third resistor is connected between the ground and a third connection node of the fifth impedance and the sixth impedance, wherein the second connection node and the third connection node are configured to connect to a balanced device.