A Double Balanced Finline Mixer with Broad if Bandwidth Capability

A novel double balanced mixer (DBM) design is reported, which is suitable to cover very broad IF-bandwidths, and overcomes the problem of IF-bandwidth restriction, co. mon to many other DBft's. The mixer utilizes bilateral finline at the RF-input and a tapered balun at the IF-output. The circuit can be produced up to the mm-wave range using low-cost planar transmission line techniques. Features of the nev design are demonstrated at the example of a mixer, that dovnconverts the entire K-band (18-26.5 GHz) to intermediate frequencies anywhere between 2-16.5 GHz or serves as an upconverter, thus extending the bandwidth of a network analyzer.