Self mixing frequency doubler tripler circuits for wireless communication

A local oscillator (LO) signal generation circuit, comprising:

• a phase locked loop to receive a reference signal and to generate a balanced input signal at an input frequency;
• and
• a frequency tripler circuit coupled to the phase locked loop to translate the balanced input signal at the input frequency to an output balanced signal having a frequency triple the input frequency, the frequency tripler circuit comprising:
• an amplifier to receive the balanced input signal at the input frequency and outputs a balanced signal at a second harmonic of the input frequency;
• and
• a double balanced mixer coupled to an output of the amplifier to receive the balanced signal at the second harmonic and the balanced input signal to generate an output balanced signal having a frequency triple the input frequency, wherein the double balanced mixer comprises:
• a third and a fourth transistors having source terminals coupled to a first of output ports of the amplifier;
• a fifth and a sixth transistors having source terminals coupled to a second of the output ports of the amplifier, wherein gate terminals of the third and the sixth transistors are coupled to a first of the balanced input signal, wherein gate terminals of the fourth and the fifth transistors are coupled to a second of the balanced input signal;
• and
• a transformer coupled to the third, fourth, fifth, and sixth transistors, wherein the transformer of the double balanced mixer comprises:
• a primary transformer winding having a first port coupled to drain terminals of the third and the fifth transistors, and a second port coupled to drain terminals of the fourth and the sixth transistors;
• and
• a secondary transformer winding having a third and a fourth ports as different output ports of the transformer, wherein a center tap of the primary transformer winding is coupled to a reference ground signal.

A frequency tripler circuit, comprising:

• an amplifier to receive a balanced input signal at an input frequency and outputs a balanced signal at a second harmonic of the input frequency, wherein the amplifier comprises a first and a second transistors, wherein source terminals of the first and second transistors are coupled to a reference ground signal and drain terminals of the first transistor and the second transistor are coupled to a common node, and the amplifier comprises a balun having a single ended port coupled to the common node and differential ports as output ports of the amplifier;
• and
• a double balanced mixer coupled to an output of the amplifier to receive the balanced signal at the second harmonic and the balanced input signal to generate an output balanced signal having a frequency triple the input frequency, wherein the double balanced mixer comprises:
• a third and a fourth transistors having source terminals coupled to a first of the output ports of the amplifier;
• a fifth and a sixth transistors having source terminals coupled to a second of the output ports of the amplifier, wherein gate terminals of the third and the sixth transistors are coupled to a first of the balanced input signal, wherein gate terminals of the fourth and the fifth transistors are coupled to a second of the balanced input signal;
• and
• a transformer coupled to the third, fourth, fifth, and sixth transistors.