Integrated mixer based on composite right/left-handed leaky-wave antenna

This paper presents a novel balanced mixer receiver front-end design based on a metamaterial structure applicable to differential-/common-mode excitation. This metamaterial structure functions as a leaky-wave antenna and provides intrinsic common-mode suppression. Low LO leakage and high RF to LO isolation are achieved without additional filters for the LO and RF paths. The metamaterial is based on a unit-cell which under a differential-mode excitation behaves like a composite right/left-handed (CRLH) metamaterial. In contrast, the metamaterial unit-cell is below cut-off under a common-mode excitation. Experimental results are used to verify the proposed metamaterial’s differential-/common-mode characteristics. The metamaterial is integrated with a balanced mixer design resulting in an operation frequency range of 1.96 GHz – 2.40 GHz with an optimum mixer conversion loss of 21.1 dB at 2.4 GHz.