A highly linear short-wave broadband double-balanced mixer

A short-wave broadband mixer with high linearity based on double-balanced structure is presented. The mixer is realized by double-balanced passive COMS FET array and balun technology. The channel-width and the bias-voltage of the FET are adjusted to optimize the mixer´s performance. The balun is implemented by radio frequency ferrite transmission line transformer that has low insertion loss over wide bandwidth. The radio frequency (RF) frequency is 1.5~30MHz, the local oscillator frequency (LO) is 71.5~100MHz and the intermediate frequency (IF) is 70MHz. The test results show that the conversion loss is about 6.5 dB, the referred 1-dB compression point (P1dB) is above 12dBm, the LO-IF isolation is above 65dB, the LO-RF isolation is above 70dB and the third order input intercept point (IIP₃) is above 45dBm.