Patent ID: 6026287
Filing Date: 2000-02-15
Classification: H03D,H03H

Abstract:
A device for mixing an input signal (I.sub.RF) having a first frequency (RF) with an input signal (I.sub.LO) coming from a local oscillator having a second frequency (LO) and for producing an output signal (O.sub.IF) having an intermediate frequency (IF), with rejection of the harmonics of the second frequency (LO) up to an order higher than the tenth order, said device comprising:a ring mixer (17) of double balanced field effect transistors (12, 13, 14, 15), the mixer having a first and a second pair of input terminals (3, 4; 1, 2) and having a pair of output terminals (5, 6); anda first and a second coupler (18, 19) respectively comprising a phase splitter and a phase combiner for said input signal (I.sub.RF) which has the first frequency (RF) and the output signal (O.sub.IF) which has the intermediate frequency (IF), connected to the first pair of input terminals (3, 4) and to the pair of output terminals (5, 6) of the ring mixer (17), respectively;wherein the first and second couplers (18, 19) each comprise a first and a second identical passive phase-shifter sub-circuit (300, 400; 500, 600) respectively, formed by isolated elements and symmetrically mounted so that the respective impedances on the terminals of the first input pair and on the terminals of the output pair of the mixer are identical.