Direct-coupled active balanced mixer

DETAILED DESCRIPTION A low-power, high performance mixer according to the invention includes a diode ring and first and second active baluns.
The first active balun has an input coupled to a radio frequency (PAT) signal.
The first active balun generates a first intermediate frequency (IF) output and a set of balanced RF outputs which are directly coupled to the diode ring.
The second active balun has an input coupled to a local oscillator (LO) signal.
The second active balun generates a second IF output and a set of balanced LO outputs which are directly coupled to the diode ring.
In accordance with a preferred embodiment of the invention, the first active balun includes a plurality of transistors.
A non-inverting RF output of the first active balun is directly coupled to an anode of the first diode.
The inverting RF output of the first active balun is directly coupled to an anode of the third diode.
The second active balun includes a plurality of transistors.
A non-inverting LO output of the second active balun is directly coupled to an anode of the fourth diode.
An inverting LO output of the second active balun is directly coupled to an anode of the second diode.
In accordance with another preferred embodiment of the invention, the active balanced mixer has wideband operation.
The wideband mixer includes a diode ring and a first distributed device having an input coupled to a radio frequency signal and a first plurality of differential amplifiers.
The first distributed device generates a first intermediate frequency output and a set of balanced radio frequency outputs which are directly coupled to the diode ring.
A second distributed device has an input coupled to a local oscillator signal and includes a second plurality of distributed amplifiers.
The second distributed device generates a second intermediate frequency output and a second set of balanced local oscillator outputs which are directly coupled to the diode ring.
In another aspect of the invention, a wideband mixer includes a diode ring and first and second distributed active baluns