A Proof of Concept Balanced Mixer with the use of a Digital IF Power Combiner to Improve LO Noise Rejection

In this work we present a novel digital technique, that allows local oscillator (LO) noise cancellation using a digital power combiner in a balanced mixer receiver architecture. A theoretical analysis of the noise cancellation using the proposed technique is derived and a proof of concept experiment is made for the Ku-Band. This experiment includes the design and construction of a custom balanced mixer and an artificial noise source. Experimental results show a consistent noise temperature reduction in comparison with a full analog mixer, and in some cases reaching noise temperature levels similar to the receiver operating without the artificial LO noise.