Miniaturized multi-layer balun

A miniaturized multi-layer balun comprising:

• an unbalanced port;
• first and second balanced ports;
• first and second capacitive elements, each capacitive element having first and second ends, the first end of said first capacitive element being connected to said unbalanced port and the second end of said first capacitive clement being connected to a ground, both ends of said second capacitive element being connected to the first and second balanced ports respectively;
• first and second transmission lines, each having first and second ends, the first end of said first transmission line being connected to said unbalanced port and the second end of said first transmission line being connected to a ground, both ends of said second transmission line being connected to the first and second balanced ports respectively;
• at least one section of broadside coupled lines, each section having first and second coupled lines, the first coupled line of each section being connected in series between two ends of said first transmission line, the second coupled line of each section being connected in series between two ends of said second transmission line;
• and
• a ground connection having first and second ends, the first end of said ground connection being connected to the second transmission line between two central second coupled lines, and the second end of said ground connection being connected to a ground.