Broadside-coupled transformer

Impedance transformation circuitry having a first port, a second port, and a third port comprising:

• a broadside-coupled transformer comprising:
• a dielectric substrate having a frontside and a backside, wherein the backside has a ground plane disposed thereon;
• a first planar conductor disposed on the frontside of the dielectric substrate and having a first end and a second end;
• a second planar conductor positioned over and spaced apart from the first planar conductor and having a third end and a fourth end wherein the fourth end is electrically coupled to the first end of the first planar conductor;
• and
• support posts that each have a bottom attached to the dielectric substrate without contacting the first planar conductor and a top attached to a surface of the second planar conductor to support the second planar conductor over the first planar conductor;
• and
• an input matching circuit section coupled between the first port, the first end of the first planar conductor, the third port and the ground plane, wherein the input matching circuit section is tuned to extend bandwidth of the broadside-coupled transformer towards lower frequencies.