US Patent 7880557 Hybrid marchand/back-wave balun and double balanced mixer using same

A hybrid Marchand/back-wave balun includes a first pair of coupled sections having a first primary section and first secondary section; a second pair of coupled sections having a second primary section and second secondary section; a first reactance interconnecting the first and second primary sections and a second reactance interconnecting the first and second secondary sections; one of the reactances being open at high frequency and shorted at low frequency, the other reactance being shorted at high frequency and open at low frequency for selectively providing low frequency Marchand/high frequency back-wave function and high frequency Marchand/low frequency back-wave function; and a double balanced mixer using same.