Broadband monolithic passive baluns and monolithic double-balanced mixer

The authors present the design and fabrication of four broadband monolithic passive baluns including CPW (coplanar waveguide) Marchand, multilayer MS Marchand, planar-transformer, and broadside-coupled line baluns. Operational frequencies range from 1.5 GHz to 24 GHz. Maximum relative bandwidths in excess of 3:1 are achieved. Simulated performances using full wave electromagnetic analysis are in good agreement with the measured results. The design of a monolithic double-balanced diode mixer using two planar-transformer baluns is also presented. Without DC bias, the mixer shows a minimum conversion loss of 6 dB with the RF at 5 GHz and a LO (local oscillator) drive of 15 dBm at 4 GHz. The measured input IP/sub 3/ (third-order intercept point) of this mixer is better than 15 dBm over the 4 to 5.75 GHz frequency band.<>