Implementation of a quadrature hybrid for miniature mixer application

A quadrature hybrid using high-pass and low-pass lumped elements without via-hole structure for single balanced mixer application is presented. The proposed hybrid, different from those of conventional quadrature hybrid applications, can provide not only compact size but also DC block function which is very suitable for MMIC design. Application to the mixer is presented. The best conversion loss of 5.1 dB at 37 GHz and a conversion loss greater than 11 dB for wide IF bandwidth from DC to 10 GHz can be achieved. When compared with the conventional single balanced mixers, more than 50% area reduction can be obtained. The chip core area of the mixer is as small as 0.48 mm².