Unilateral microstrip balanced and doubly balanced mixers

Approaches to the unipolar realization of balanced and doubly balanced microstrip mixers are discussed. Several novel mixer designs are presented which can be used for miniaturization or for broadbanding the performance, using simple, noncritical branchline structures. The feasibility of the structures is verified experimentally. Relative bandwidths up to approximately 45% are reached easily. Doubly and singly balanced mixers worked equally well, with low conversion loss and noise figure across the whole X-band.<>