Double Balanced Mixers are used widely in frequency translation applications. Some of the advantages of the double balanced mixer are good L-R and L-I isolation and moderate R-I isolation. Triple Balanced Mixers (also called Double Doubly-Balanced Mixers) have three separate baluns for LO, RF and IF ports. This structure helps provide wide bandwidth and good L-R, L-I and R-I isolations, return loss, compression and IP3, all at the expense of 3 dB higher LO power. The usual disadvantages of a triple balanced mixer are the number of components that results in large size, and the complexity that makes it an expensive design. Mini-Circuits has overcome these disadvantages by designing a new patented LTCC (Low temperature Co-fired Ceramic) based mixer, substantially reducing the size and complexity. It uses a combination of LTCC baluns, a single ferrite-core balun, and integrated Schottky diode quads to realize a small triple balanced mixer.
