The comparison of four types L-band GaAs monolithic mixer using two common-gate MESFETs as the input stage

Four types of single-gate MMIC MESFET mixers for L-band operation have been designed, simulated and compared. All of the designs use an active adder consisting of two common-gate MESFETs as their input stage and a source follower as their output stage for good RF/LO isolation and input/output impedance matching is employed. By inserting an interstate match network between the mixer stage and the IF output buffer, a notable gain improvement and a certain degree of spurious rejection could be achieved. Also the effect of an off-chip drain choke on the conversion gain, output P_{1 dB} and 2 tone I_P3, LO/RF and LO/IF isolations, as well as the input return loss on RF, LO and IF ports. These circuits can be utilized in the transceiver front-end of personal wireless communicate systems