Bidirectional variable gain amplification

An apparatus comprising:

• an antenna element of an antenna array configured to:
• transmit a phase-shifted transmit signal;
• and
• receive an input receive signal;
• and
• a wireless transceiver comprising:
• a transmit path coupled to the antenna element;
• a receive path coupled to the antenna element;
• and
• a phase shifter disposed in both the transmit path and the receive path, the phase shifter configured to operate in an active mode to:
• generate the phase-shifted transmit signal based on an input transmit signal accepted at a shared node of the phase shifter;
• and
• generate a phase-shifted receive signal at the shared node based on the input receive signal,
• the phase shifter comprising vector modulation means for adjusting amplitudes of two split transmit signals that are associated with the input transmit signal and adjusting amplitudes of two split receive signals that are associated with the input receive signal.

A method comprising:

• operating a phase shifter in an active mode during a first time interval and a second time interval;
• accepting an input transmit signal at a shared node of the phase shifter during the first time interval;
• generating, using a first bidirectional variable gain amplifier of the phase shifter and a second bidirectional variable gain amplifier of the phase shifter, a phase-shifted transmit signal at a transmit node of the phase shifter during the first time interval, the phase-shifted transmit signal based on the input transmit signal;
• accepting an input receive signal at a receive node of the phase shifter during the second time interval;
• and
• generating, using the first bidirectional variable gain amplifier and the second bidirectional variable gain amplifier, a phase shifted receive signal at the shared node during the second time interval, the phase-shifted receive signal based on the input receive signal.

An apparatus comprising:

• at least one bidirectional variable gain amplifier comprising:
• two or more ports, the two or more ports comprising a first port and a third port, the first port configured to selectively be an input and an output of the at least one bidirectional variable gain amplifier;
• and
• a T-network coupled between the two or more ports, the T-network comprising:
• a common node;
• a first branch circuit coupled between the first port and the common node, the first branch circuit comprising a first set of transistors;
• a second branch circuit coupled to a supply voltage and the common node, the second branch circuit comprising a second set of transistors;
• and
• a third branch circuit coupled between the third port and the common node, the third branch circuit comprising a third set of transistors.

A method comprising:

• operating a bidirectional variable gain amplifier in an active transmit configuration during a first time interval, the bidirectional variable gain amplifier comprising a first port and a third port;
• amplifying a first signal that propagates from the first port to the third port in the active transmit configuration;
• operating the bidirectional variable gain amplifier in an active receive configuration during a second time interval;
• and
• amplifying a second signal that propagates from the third port to the first port in the active receive configuration.