Direct-coupled FET frequency multiplier and mixer circuit

A frequency multiplier and mixer circuit comprising:

• a first pair of input terminals for receiving a signal to be frequency-multiplied;
• a second pair of input terminals for receiving a mixing signal;
• an output terminal for outputting an output signal;
• a frequency multiplier circuit composed of a first differential amplifier, which includes first and second differential circuits, said first differential circuit being formed of source-coupled first and second field effect transistors having their respective driving powers in a ratio of K:1 where K is a positive real number excluding 1, and said second differential circuit being formed of source-coupled third and fourth field effect transistors having their respective driving powers in a ratio of 1:K, sources of said first and second field effect transistors being connected in common to a first constant current source, and sources of said third and fourth field effect transistors being connected in common to a second constant current source, gates of said first and third field effect transistors having different driving powers being connected in common to one terminal of said first pair of input terminals, and gates of said second and fourth field effect transistors having different driving powers being connected in common to the other terminal of said first pair of input terminals, drains of said first and fourth field effect transistors having the same driving power being connected to a first node of a pair of output nodes, and drains of said second and third field effect transistors having the same driving power being connected to a second node of said pair of output nodes;
• a current mirror means having an input current path connected to said first node of said pair of output nodes so as to flow a differential current between said pair of output nodes, and a mirror current path;
• and
• a mixing circuit composed of a second differential amplifier, which includes a pair of inputs connected to said second pair of input terminals, one end of one main current path of two main current paths of said second differential amplifier being connected to said output terminal, the other end of each of said two main current paths being connected in common to said mirror current path of said current mirror means.