Patent ID: 7263343

Claim:
A frequency converter performing dual frequency conversion of a first signal by using two signals including a second signal and a third signal and performing dual frequency conversion of the first signal by using two signals including the second signal and a fourth signal, the frequency converter comprising: a first switching circuit for performing a first frequency conversion by mixing the first signal and the second signal; a second switching circuit for performing a second frequency conversion by mixing a signal output from the first switching circuit and the third signal; a third switching circuit for performing a second frequency conversion by mixing the signal output from the first switching circuit and the fourth signal; and a balun having input terminals and output terminals, wherein: the output terminals of the balun are coupled to input terminals of the first switching circuit; and the first signal is introduced via the input terminals of the balun; the balun comprises two inductors alternatively formed on a semiconductor substrate, one of the inductors forming an input-side inductor and the other inductor forming an output-side inductor; and the first switching circuit, the second switching circuit, and the balun are formed on the same semiconductor substrate.