Radio frequency splitter

A radio frequency system comprising:

• an input circuit configured to receive a baseband signal and to provide a signal to be transmitted;
• a multichannel splitter coupled to receive the signal to be transmitted, the multichannel splitter comprising a plurality of output terminals;
• and
• a transmit circuit having a plurality of input terminals coupled to the output terminals of the multichannel splitter and also having a plurality of output terminals coupled a plurality of antenna nodes;
• wherein the multichannel splitter comprises a plurality of 1 to 2 splitters;
• wherein an input terminal of a first 1 to 2 splitter defines an input of the multichannel splitter and is coupled to receive the signal to be transmitted;
• wherein the 1 to 2 splitters are electrically series-connected;
• wherein first respective outputs of the 1 to 2 splitters define the output terminals of the multichannel splitter;
• wherein each 1 to 2 splitter comprises:
• a first λ/4 line having a first end and a second end;
• a second λ/4 line having a first end and a second end, wherein the first end of the first λ/4 line and the first end of the second λ/4 line are connected together and form an input of the 1 to 2 splitter;
• and
• an impedance connected between the second end of the first λ/4 line and the second end of the second λ/4 line, wherein the second end of the first λ/4 line forms a first output of the 1 to 2 splitter and wherein the second end of the second λ/4 line forms a second output of the 2 to 1 splitter.

A system comprising:

• an electronic transmit circuit having a receive input and a transmit output;
• a digital to analog converter with an input coupled to the transmit output of the electronic transmit circuit;
• an analog to digital converter with an output coupled to the received input of the electronic transmit circuit;
• a first modulation circuit with an input coupled to an output of the digital to analog converter;
• a second modulation circuit with an output coupled to an input of the analog to digital converter;
• a multichannel splitter with an input coupled to an output of the first modulation circuit, the multichannel splitter also having a plurality of outputs;
• a first plurality of amplifiers, each amplifier having an input coupled to a corresponding output of the multichannel splitter;
• a multichannel combiner with an output coupled to an input of the second modulation circuit, the multichannel combiner also having a plurality of inputs;
• and
• a second plurality of amplifiers, each amplifier having an output coupled to a corresponding input of the multichannel combiner;
• wherein the multichannel splitter comprises a plurality of 1 to 2 splitters;
• wherein an input terminal of a first 1 to 2 splitter defines an input of the multichannel splitter and is coupled to the output of the first modulation circuit;
• wherein the 1 to 2 splitters are electrically series-connected;
• wherein first respective outputs of the 1 to 2 splitters define the outputs of the multichannel splitter;
• wherein each 1 to 2 splitter comprises:
• a first λ/4 line having a first end and a second end;
• a second λ/4 line having a first end and a second end, wherein the first end of the first λ/4 line and the first end of the second λ/4 line are connected together and form an input of the 1 to 2 splitter;
• and
• an impedance connected between the second end of the first λ/4 line and the second end of the second λ/4 line;
• and
• wherein the second end of the first λ/4 line forms a first output of the 1 to 2 splitter and wherein the second end of the second λ/4 line forms a second output of the 2 to 1 splitter.

A multichannel combiner comprising:

• a plurality of 1 to 2 combiners;
• wherein an output terminal of a first 1 to 2 combiner defines an output of the combiner;
• wherein each 1 to 2 combiner is electrically series-connected with another 1 to 2 combiner;
• wherein first respective inputs of the 1 to 2 combiners define the inputs of the combiner;
• wherein each 1 to 2 combiner comprises:
• a first λ/4 line having a first end and a second end;
• a second λ/4 line having a first end and a second end, wherein the first end of the first λ/4 line and the first end of the second λ/4 line are connected together and form an input of the 1 to 2 combiner;
• an impedance connected between the second end of the first λ/4 line and the second end of the second λ/4 line;
• and
• wherein the second end of the first λ/4 line forms a first output of the 1 to 2 combiner and wherein the second end of the second λ/4 line forms a second output of the 2 to 1 combiner.