Patent ID: 6242964
Filing Date: 2001-06-05
Classification: H03D

Abstract:
An augmented lossless feedback double-balanced active mixer circuit for mixing an input intermediate frequency (IF) signal and an input local oscillator (LO) signal and producing an output radio frequency (RF) signal comprising:a first pair of input terminals for receiving differential first and second IF input signals;a second pair of input terminals for receiving differential first and second LO input signals;an output terminal for providing an RF output signal;a first augmented lossless feedback balanced active mixer circuit having an IF input connected to the first IF signal input terminal of the augmented lossless feedback double-balanced active mixer circuit, differential first and second LO inputs connected one each to the differential first and second LO signal input terminals of the augmented lossless feedback double-balanced active mixer circuit, and an RF output connected to the RF output terminal of the augmented lossless feedback double-balanced active mixer circuit, the first augmented lossless feedback balanced mixer circuit further comprising:a first common-base transistor amplifier, having an input, an output, and a control, further comprising a first bipolar transistor having an emitter, a base, and a collector coupled to the input, control, and output, respectively, of the first common-base transistor amplifier,a first hybrid transformer, consisting of a primary winding having a first and second input and a centre-tap output, and a secondary winding with a first and second end, the first end connected to the RF output of the first augmented lossless feedback balanced mixer circuit and the second end connected to a signal ground,a first differential pair of switching transistors, each having a collector, an emitter, and a base, the collector of the first differential transistor connected to the first input of the first hybrid transformer, the collector of the second differential transistor connected to the second input of the first hybrid transformer, the bases of the differential transistors connected one each to the LO inputs of the first augmented lossless feedback balanced active mixer circuit, and the emitters of both differential transistors connected in common to the first common-base transistor amplifier output,a first lossless feedback transformer consisting of an input winding having a first end and a second end, the first end of the input winding connect to the IF input of the first augmented lossless feedback balanced mixer circuit and the second end of the input winding connected to the first common-base transistor amplifier input, and a tapped output winding having a first end, a second end, and a tap, the first end of the output winding connected to the primary centre tap of the first hybrid transformer and the second end of the output winding connected to a signal ground,a first augmentation circuit having an input and an output, the input coupled to the first common-base transistor amplifier input and the output coupled to the first common-base transistor amplifier control, anda first load resistor having a first end and a second end, the first end of the first load resistor connected to the output winding tap of the first lossless feedback transformer and the second end of the first load resistor connected to a signal ground; anda second augmented lossless feedback balanced active mixer circuit having an IF input connected to the second IF signal input terminal of the augmented lossless feedback double-balanced active mixer circuit, differential first and second LO inputs connected one each to the differential first and second LO signal input terminals of the augmented lossless feedback double-balanced active mixer circuit, and an RF output connected to the RF output terminal of the augmented lossless feedback double-balanced active mixer circuit, the second augmented lossless feedback balanced mixer circuit further comprising:a second common-base transistor amplifier, having an input, an output, and a control, further comprising a second bipolar transistor having an emitter, a base, and a collector coupled to the input, control, and output, respectively, of the second common-base transistor amplifier,a second hybrid transformer, consisting of a primary winding having a first and second input and a centre-tap output, and a secondary winding with a first and second end, the first end connected to the RF output of the second augmented lossless feedback balanced mixer circuit and the second end connected to a signal ground,a second differential pair of switching transistors, each having a collector, an emitter, and a base, the collector of the first differential transistor connected to the first input of the second hybrid transformer, the collector of the second differential transistor connected to the second input of the second hybrid transformer, the bases of the differential transistors connected one each to the LO inputs of the second augmented lossless feedback balanced active mixer circuit, and the emitters of both differential transistors connected in common to the second common-base transistor amplifier output,a second lossless feedback transformer consisting of an input winding having a first end and a second end, the first end of the input winding connect to the IF input of the second augmented lossless feedback balanced mixer circuit and the second end of the input winding connected to the second common-base transistor amplifier input, and a tapped output winding having a first end, a second end, and a tap, the first end of the output winding connected to the primary centre tap of the second hybrid transformer and the second end of the output winding connected to a signal ground,a second augmentation circuit having an input and an output, the input coupled to the second common-base transistor amplifier input and the output coupled to the second common-base transistor amplifier control, anda second load resistor having a first end and a second end, the first end of the first load resistor connected to the output winding tap of the second lossless feedback transformer and the second end of the first load resistor connected to a signal ground.