Doherty Amplifier with Input Network Optimized for MMIC

An electronic circuit comprising a Doherty amplifier for use in a frequency band, wherein the Doherty amplifier comprises:

• an input operative to receive an input signal;
• an output operative to supply an output signal;
• a main device interposed between the input and the output;
• a peak device interposed between the input and the output;
• and
• an input combiner connecting the input to an input node of the main device and to an
• input node of the peak device, the input combiner comprising
• a first branch between the input and the input node of the main device so as to implement a first frequency-dependent input impedance with a first real part and a first imaginary part as considered from the input node;
• and
• a second branch between the input and the input node of the peak device so as to implement a second frequency-dependent input impedance with a second real part and a second imaginary part as considered from the input node;
• wherein the first and second imaginary parts have opposite polarity;
• wherein the first and second imaginary parts have substantially a same magnitude so as to substantially compensate each other in the frequency band;
• wherein the first imaginary part and the second imaginary part implement a first phase shift in the first branch and a second phase shift in the second branch, respectively;
• and
• wherein the first and second phase shifts each have a magnitude of substantially 45 degrees substantially in the middle of the frequency band, and have opposite polarity.

A wireless communication device, including a Doherty amplifier operative to amplify wireless communication signals in a frequency band, the amplifier comprising:

• an input operative to receive an input signal;
• an output operative to supply an output signal;
• a main device interposed between the input and the output;
• a peak device interposed between the input and the output;
• and
• an input combiner connecting the input to an input node of the main device and to an
• input node of the peak device, the input combiner comprising
• a first branch between the input and the input node of the main device so as to implement a first frequency-dependent input impedance with a first real part and a first imaginary part as considered from the input node;
• and
• a second branch between the input and the input node of the peak device so as to implement a second frequency-dependent input impedance with a second real part and a second imaginary part as considered from the input node;
• wherein the first and second imaginary parts have opposite polarity;
• wherein the first and second imaginary parts have substantially a same magnitude so as to substantially compensate each other in the frequency band;
• wherein the first imaginary part and the second imaginary part implement a first phase shift in the first branch and a second phase shift in the second branch, respectively;
• and
• wherein the first and second phase shifts each have a magnitude of substantially 45 degrees substantially in the middle of the frequency band, and have opposite polarity.