Patent ID: 7005956

Claim:
A balance-to-unbalance (Balun) transformer structure ( 10 ), comprising: an input terminal ( 11 ); a first output terminal ( 12 ); a second output terminal ( 13 ); a first circuit line, which comprises at least two capacitors (C 1 , C 2 ) in parallel with each other and a first inductor L 1 in series with the capacitors (C 1 , C 2 ), wherein one electrode of each of the capacitors (C 1 , C 2 ) are grounded; and a second circuit line, which comprises at least two capacitors (C 3 , C 4 ) in series with each other and a second inductor (L 2 ) in parallel with the capacitors (C 3 , C 4 ), wherein one end of the second inductor (L 2 ) is grounded, wherein one end of the first circuit line and one end of the second circuit line are connected in parallel with the input terminal ( 11 ), and the other ends of the first and second circuit lines are the first and second output terminals, respectively.