Wireless device with a multi-turn directional coupler

A directional coupler, comprising:

• a main line provided on a first metallic layer of a substrate, the main line having a first end connected to a first port and a second end connected to a second port, the main line comprising a first plurality of turns;
• and
• a coupled line disposed on a second metallic layer of the substrate, the coupled line comprising a single conductor line having a first end connected to a third port and a second end connected to a fourth port, wherein:
• the first metallic layer with the main line is electrically isolated from the second metallic layer of the coupled line via an isolation layer of the substrate;
• the coupled line comprises a second plurality of turns forming a plurality of windings within the second metallic layer, one or more of the second plurality of turns overlapping at least partially with more than one turn of the first plurality of turns of the main line;
• and
• the main line and the coupled line are routed so that electric signals on both lines propagate in a same direction, enhancing inductive coupling by mutual inductance between the main line and the coupled line.

An apparatus of a wireless communication device, the apparatus comprising:

• a directional coupler, the coupler comprising:
• a main line having a first end connected to an input port and a second end connected to an output port, the main line comprising a first plurality of turns;
• and
• a coupled line having a first end connected to a coupled port and at a second end connected to an isolated port;
• wherein the coupled line comprises a single conductor line with a second plurality of turns forming a winding, a portion of the winding overlaps with at least two of the first plurality of turns forming the main line, and wherein the coupled port, the isolated port and the single conductor line are within a same metallic layer which is isolated from the coupled line;
• a power amplifier coupled to the input port of the main line;
• and
• processing circuitry to measure forward power of a transmit signal output by the amplifier at the input port, and adjust signal amplification by the power amplifier based on the measured forward power.